Tesi: "Pollination by insects"

1

Cunnold, Helen Elizabeth. "Distinguishing pollination from visitation : the value of a pollinator effectiveness and pollinator importance network". Thesis, University of St Andrews, 2018. http://hdl.handle.net/10023/16121.

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For over twenty years, flower-visitation networks have been used to assess the effects of pollinator decline, linked to habitat loss, climate change and invasive species, on entire communities. However, most rely on flower visit frequency as a proxy for pollination; very few sample pollen from flower visitor's bodies or from stigmas and so do not include a quantitative measure of pollination success. Here, I add pollinator effectiveness (as single visit pollen deposition) into a traditional flower visitation network, creating a pollinator importance network that better evaluates the flower visitor community from the plant's perspective. Given recent interest in pollination in urban areas, I use an urban garden habitat, and compare visitation, pollen transport and pollinator importance networks, giving several novel conclusions. Firstly, although there are similarities in the structure of my networks, interactions were most specialised in the pollinator importance network, with pollen transport proving to be a better proxy for pollinator importance than visitation alone. Secondly, the specialisation of individual plants and the role of individual flower visitors varied between the networks, suggesting that community-level patterns in simple visitation networks can mask important individual differences. Thirdly, the correlation between flower visit frequency and pollinator importance largely depends on bees, and may not hold in plant-pollinator communities that are not bee-dominated. Fourthly, heterospecific pollen deposition was relatively low, despite the unusually diverse plant community of a garden. Finally, bees (particularly Bombus and non-eusocial halictids) carried the largest pollen loads and were the most effective at depositing pollen on to the stigma during a single visit in this garden habitat. The implications of this thesis highlight the strengths and limitations of each network for future studies, and raise important questions for the future of urban pollination studies.

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2

Gryj-Rubenstein, Ellen Orli. "Conflicting forces shaping reproductive strategies of plants : florivory and pollination /". Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/5126.

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3

Vezvaei, Ali. "Pollination studies in almond". Title page, contents and summary only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phv597.pdf.

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4

Hagler, James Robert. "Basic aspects of onion pollination". Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184512.

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Difficulties in pollen transfer have adversely affected seed production of hybrid onion (Allium cepa L.) in the United States. Six onion cultivars were examined for differential attractiveness to the honey bee (Apis mellifera L.). Honey bees clearly discriminated between the onion cultivars in both open plots and caged plots. Nectar secretion, nectar sugar concentration, nectar sugar composition, mectar potassium content, and flower phenology were correlated with honey bee visitation. Nectar secretion rates ranged from 0.54 to 0.84 ul per floret per day. Onion cultivars also demonstrated differential flowering potential. The cultivars produced from 176 to 359 flowers per umbel with 32 to 74 umbels per 30 onions. All onion cultivars examinaed contained viscous nectar with sugar concentrations ranging from 51 to 65% of total dissolved solids. Onion nectar was analyzed by gas chromatography to determine qualitative sugar differences among onion cultivars. All cultivars were hexose dominant with an approximately 1:1 fructose:glucose ratio. However, fructose was slightly more abundant than glucose. Sucrose was much less abundant than the hexose sugars. Atomic absorption spectrophotometry revealed little difference in potassium content among the A. cepa cultivars. Nectar potassium levels ranged from 5,300 ppm to 6,900 ppm. Cultivars with higher nectar potassium levels had fewer honey bee visits. Two honey bee bioassays were conducted. The first bioassay simulated the sugar and potassium composition of each onion cultivar. The honey bees selectively foraged on simulated nectars with low potassium and high sugar concentrations. The second bioassay was designed to test honey bee response to "phenolic-rich" solutions. The natural compounds tested were dilutions of salt cedar (Tamarix pentandra Pall.) honey, almond (Prunus dulcis Mill.) honey, and aloe (Aloe littoralis L.) nectar. The pure synthetic compounds tested were caffeic acid and genestic acid. Generally, honey bees foraged preferentially on the lower phenolic concentrations, indicating that compounds high in phenolic composition inhibit honey bee foraging. Finally, seed yields of each of the cultivars were compared. Wide variations in yields were correlated with honey bee visitation, sugar composition, potassium levels, and flower phenology.

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5

Wilson, Trevor Craig. "Evolution of pollination in prostanthera labill. (lamiaceae)". Thesis, The University of Sydney, 2010. https://hdl.handle.net/2123/28905.

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Prostanthera Labill. (Lamiaceae) is traditionally divided into section Klanderia (F. Muell.) Benth. and section Prostanthera based on floral characteristics that correspond to putatively ornithophilous or entomophilous pollination syndromes. To better understand these pollination syndromes and how they evolved, the phylogenetic relationships, floral morphology, and pollination of Prostanthera were investigated. Maximum parsimony and Bayesian phylogenies for 66 (~75%) species of Prostanthera were constructed using chloroplast (trnT-F, nth-rpl32) and nuclear (ETS) genomes. In all cases Prostam‘hera was found to be paraphyletic with respect to Wrixonia. Prostanthera section Prostanthera was revealed to be paraphyletic relative to section Klanderia. A multivariate morphometric analysis of floral characteristics was also congruent with the molecular phylogenies and identified a single putatively ornithophilous group and two putatively entomophilous groups. Quantitative analyses of pollinator visitation further supported hypotheses derived from the analysis of nucleotide data and multivariate morphometrics and identified functional pollinator groups for each clade. Ancestral state reconstruction using squared-change parsimony of geometric morphometric landmark data provided insights into the ancestral pollination syndrome and evolutionary changes necessary to optimise corolla morphology for each clade. It is concluded that ancestral Prostanthera was likely pollinated by a diverse range of insects and possibly even birds. The evolution of an ornithophilous clade and a generalist entomophilous clade correspond with separate modifications to the lobes and tube of the corolla. The combination of phylogenetic and morphological data from this study provides a robust understanding of relationships and an insight to the structural changes in the evolution of pollination.

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6

Hill, Stuart John. "Pollination of almond (Prunus dulcis (Mill.) D.A. Webb)". Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09A/09ah648.pdf.

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7

Carvalho, Carolina Maria Coelho de Almeida. "Evaluation of an ecosystem service in restored quarry areas: pollination". Master's thesis, Universidade de Évora, 2020. http://hdl.handle.net/10174/27832.

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Ecological restoration allows for accelerated recovery of a degraded ecosystem’s biodiversity, function, and ability to provide ecosystem services. However, the issues of when active restoration is necessary and how restoration effectiveness should be measured are still subject to considerable debate. Here we evaluate plant-pollinator networks in actively and passively restored quarries, comparing structure and composition to a natural area representing the reference ecosystem, to determine which restoration approach holds higher effectiveness on the rehabilitation of this ecological process. We found that while both approaches allowed for the restoration of pollination function, active restoration allowed for faster recovery. Nevertheless, the distinct strategies generated key structural vegetation differences, which influenced distinct pollinator communities providing the service in different areas. These results support the idea that restoration might be attained by distinct biological communities, and that both composition and function should be taken into account when evaluating restoration outcomes; RESUMO: O restauro ecológico permite acelerar a recuperação da biodiversidade, função e serviços de um ecossistema degradado. No entanto, existe bastante debate sobre as situações em que é realmente necessário o restauro ativo e como deve ser avaliado. Neste estudo, avaliamos redes plantapolinizador em pedreiras restauradas ativamente e passivamente, comparando a sua estrutura e composição com uma área natural que representa o ecossistema de referência, para determinar a abordagem mais eficiente na reabilitação da polinização. Verificámos que, apesar de ambas permitirem o restauro desta função, o restauro ativo permite uma recuperação mais rápida. No entanto, estratégias distintas geraram diferenças estruturais na vegetação, o que influenciou o estabelecimento de comunidades de polinizadores distintas a polinizar as diferentes áreas. Estes resultados apoiam a ideia de que o restauro pode ser atingido com comunidades biológicas distintas, e que a composição e a função devem ambas ser tidas em conta na avaliação do restauro ecológico.

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8

Cerqueira, Nicole. "Pollinator visitation preference on native and non-native congeneric plants". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 2.91 Mb., 84 p, 2005. http://wwwlib.umi.com/dissertations/fullcit/1428175.

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9

Bensemann, Lauretta Lynley. "Patterns in flower visitation of flying insects in urban Christchurch". Thesis, University of Canterbury. Biological Sciences, 2013. http://hdl.handle.net/10092/9429.

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In this project I studied the importance of pollinators in the reproduction of Gastrodia ‘long column’ and the preferences of New Zealand’s native and exotic insect pollinators. This was done in order to determine the specialisation of insect pollination in urban Christchurch. This knowledge can contribute to crop pollination, conservation efforts, and an understanding of the main drivers of the common floral traits (small, white flowers) in New Zealand. The strength of the relationship between the common traits of the New Zealand flora and the preferences of the native invertebrate fauna is not known. Traditionally it had been thought that New Zealand’s insects lack strong preferences, however recent work has not supported this. Changing landscapes worldwide have led to declines in pollinator numbers. Additionally, in New Zealand Apis mellifera numbers have declined as a result of the arrival of the varroa mite and it is important that alternative pollinating species for wild and agricultural pollination are identified. To address these needs I examined the abundance and preferences of insect pollinators in modified landscapes in and around Christchurch testing: the reliance upon pollinators by the undescribed native orchid Gastrodia ‘long column’, the preferences of New Zealand’s native and introduced insect pollinators in an extensive observational study, the results of which I further tested using a subsequent manipulative experiment of petal colour (according to human vision) at the Christchurch Botanical Gardens Sampling at the Christchurch Botanical Gardens, University of Canterbury, and Port Hills across a four month observation period (January – April 2012), revealed that native pollinators preferred white native flowers and exotic pollinators preferred not-white exotic flowers when data were grouped according to insect provenance. A more detailed visit-level analysis found that two native bees, Hylaeus and Leioproctus, showed a significant preference for native flowers; the exotic bees, Apis mellifera and Bombus species, preferred purple over white flowers; and Melangyna novaezelandiae (a native hoverfly) preferred white over yellow. However, a series of experimental arrays to present controlled choices between pairs of flower types at the Christchurch Botanical Gardens (14 December 2012 – 22 January 2013) did not find significant preferences by native or exotic insect pollinators between white and yellow flowers. This may have been a result of the plant species chosen, as a correlation between pollinator preference and plant species has been shown elsewhere. Visitation to experimental arrays was both low and highly skewed, with over half of all visits made by Lasioglossum bees and 615 of the 669 visits made by native species. This may have meant that lack of significant results were representing the choices of native insects generally and Lasioglossum bees specifically. A bagging experiment from 30 January 2012 – 16 February 2012 demonstrated the dependence of the undescribed native orchid species, Gastrodia ‘long column’, upon pollinating animals. Fruit set of most plants worldwide depends upon pollination (by wind or animal-transfer of pollen). In this case study final fruit sets were significantly reduced on bagged inflorescences, while open flowers had surprisingly high natural fruit sets (>75%). A week of observations (29 January 2012 – 6 February 2012) revealed that Gastrodia ‘long column’ was predominantly visited by Lasioglossum bees, and remarkably bee numbers were high enough in a residential property in the middle of Christchurch city for high fruit set on unmanipulated plants. The results of my thesis indicate that pollinators are important in the reproductive system of Gastrodia ‘long column’, suggesting that other previously overlooked plant species may also rely upon insect pollinators. Furthermore, the relative importance of native pollinating insects is high for native plants even when examined in an urban setting. New Zealand pollinators have preferences for certain floral traits which show trends when grouped broadly, but vary when considered at the insect species level. This contrasts with traditional views of unspecialised insect pollinators which lack preferences in regards to the plants they visit. Further work which serves to increase current understanding of the underlying mechanisms of pollination specialisation in New Zealand may wish to focus on single insect species. By identifying particular preferences of pollinators and the underlying ‘native’ traits selected for, alternative options to crop pollination may be found, targeted management strategies implemented, and the strength of the relationship between pollinator preferences and the traits of the plants they visit determined.

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10

D'Avila, Márcia. "Insetos visitantes florais em áreas de cerradão e cerrado sensu stricto no estado de São Paulo". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/11/11146/tde-24012007-155752/.

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Com o objetivo de conhecer a composição dos insetos e das plantas visitadas nas áreas de cerradão e cerrado sensu stricto, da Estação Experimental de Itirapina, SP, foram realizadas amostragens sistemáticas dos insetos nas plantas, no período de março de 2003 a fevereiro de 2004. Do total de insetos coletados nas flores, 63,3% e 63,8% são da ordem Hymenoptera, 17,1% e 2,5% da ordem Lepidoptera, 16% e 19,5% da ordem Coleoptera e 3,6% e 12,8% da ordem Diptera, respectivamente, para as áreas de cerradão e cerrado sensu stricto, e 1,4% para Hemiptera-Heteroptera no cerrado sensu stricto. A maioria dos insetos coletados, visitando e/ou forrageando, nas duas áreas, foi no período da manhã, exceto os dípteros que preferiram o período da tarde. Na área de cerradão as espécies dominantes de Hymenoptera foram: Exomalopsis (Exomalopsis) sp. e Trigona spinipes; de Lepidoptera foram: Aeria olena e Ithomia agnosia; de Coleoptera foram: Nycterodina sp. e Spintherophyta sp.. Já na área de cerrado sensu stricto os hymenópteros dominantes foram: Apis mellifera, Exomalopsis cf. analis, Tetrapedia rugulosa, Trigona spinipes e Pepsis sp., para Coleoptera foram: Spintherophyta sp., Compsus sp. e Epitragus similis; para Diptera foram: Eristalis sp. e Ornidia obesa. A família Apidae foi a mais rica em espécies e abundância, nas duas áreas de cerrado, seguindo o padrão geral encontrado em outras áreas neotropicais até o momento estudadas, apresentando muitas espécies com poucos indivíduos e poucas espécies com muitos indivíduos. Quanto a composição da flora, em ordem decrescente, as famílias Asteraceae, Melastomataceae, Apocynaceae, Malpighiaceae e Rubiaceae foram as mais representativas na área de cerradão. Na área de cerrado sensu stricto as famílias com maior número de espécies foram Fabaceae, Malpighiaceae, Asteraceae, Bignoniaceae e Myrtaceae. As espécies vegetais com maior percentual de insetos visitantes na área de cerradão foram Diplosodon virgatus (Lythraceae), Daphnopsis racemosa (Thymelaeaceae) e Borreria verticillata (Rubiaceae), e no cerrado sensu stricto foram Ocotea pulchella (Lauraceae) e Miconia rubiginosa (Melastomataceae). A família Apidae foi a que visitou maior número de espécies botânicas, seguida por Nymphalidae, Chrysomelidae, Halictidae e Vespidae, na área de cerradão. No cerrado sensu stricto foram Apidae, Syrphidae, Chrysomelidae, Curculionidae, Halictidae, Vespidae e Pompilidae. Dos insetos dominantes, Apis mellifera foi a que visitou o maior número de espécies de plantas, seguida de Exomalopsis (Exomalopsis) sp., Aeria olena e Trigona spinipes, no cerradão; e no cerrado sensu stricto foram Apis mellifera, Trigona spinipes, Exomalopsis cf. analis e Tetrapedia rugulosa.
Systematic samplings of insects on plants were carried out with the aim of studying the insect composition and visited plants in cerradao and cerrado areas stricto sensus at the Experimental Station of Itirapina ? SP between March 2003 and February 2004. Considering all insects collected on flowers in the cerradao and cerrado areas stricto sensus , 63.3% and 63.8% were Hymenoptera, 17.1% and 2.5% were Lepidoptera, 16.0% and 19.5% were Coleoptera and 3.6% and 12.8% were Diptera, respectively, while in the cerrado stricto sensus 1.4% were Hemiptera-Heteroptera. Most insects collected were visiting and/or foraging in the areas during the morning, except for diptera, which preferred the afternoon period. The dominant species within each order in the cerradao area were: Hymenoptera - Apis mellifera, Exomalopsis (Exomalopsis) sp. and Trigona spinipes; Lepidoptera - Aeria olena and Ithomia agnosia; Coleoptera - Nycterodina sp. and Spintherophyta sp.. In the cerrado area stricto sensus the dominant species were: Hymenoptera - Apis mellifera, Exomalopsis cf. analis, Tetrapedia rugulosa, Trigona spinipes and Pepsis sp.; Coleoptera - Spintherophyta sp., Compsus sp. and Epitragus similis; Diptera - Eristalis sp. and Ornidia obesa. The Apidae Family was the richest in species and most abundant in both cerrado areas, following the general pattern of other Neotropical areas already studied, with many species with few individuals and few species with many individuals. Regarding the floristic composition, the most representative families in the cerradao area were, in order, Asteraceae, Melastomataceae, Apocynaceae, Malpighiaceae and Rubiaceae. Families with most species in the cerrado area stricto sensus were Fabaceae, Malpighiaceae, Asteraceae, Bignoniaceae and Myrtaceae. The plant species in the cerradao area with the greatest percentage of visiting insects were Diplosodon virgatus (Lythraceae), Daphnopsis racemosa (Thymelaeaceae) and Borreria verticillata (Rubiaceae), while in the cerrado stricto sensus they were Ocotea pulchella (Lauraceae) and Miconia rubiginosa (Melastomataceae). The Apidae family was the one visiting most plant species in the cerradao area, followed by Nymphalidae, Chrysomelidae, Halictidae and Vespidae families, while in the cerrado stricto sensus the families visiting most plant species were Apidae, Syrphidae, Chrysomelidae, Curculionidae, Halictidae, Vespidae and Pompilidae. Apis mellifera was the species among the dominant insects of the cerradao area which visited the greatest number of plant species, followed by Exomalopsis (Exomalopsis) sp., Aeria olena and Trigona spinipes. In the cerrado stricto sensus the insect species that visited the greatest number of plants were Apis mellifera, Trigona spinipes, Exomalopsis cf. analis and Tetrapedia rugulosa.

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11

Tarrant, Sam. "The potential of restored landfill sites to support pollinating insects". Thesis, University of Northampton, 2009. http://nectar.northampton.ac.uk/3595/.

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Habitat restoration is an important tool in reducing the current decline in biodiversity. To determine the success of restoration, ecologists have previously focused on species richness or on the presence of rare species; little is known of species interactions. This study examines both the potential of restored landfill sites to support pollinating insects and how flower-insect interactions can be used in determining successful restoration. These are important attributes of ecosystem function. Standard belt transects were used to record flowering insect pollinated plants and flower-visiting insects on nine paired restored landfill and reference nature sites, in the broader Northamptonshire region (UK). Over the duration of this study, an area of 25,000m2 was surveyed for floral characteristics and approximately 138,000 floral units were counted from 98 plant species. A total of 201 flower visitor surveys were performed, with 942 flower-visiting insect samples taken. Flowering plant species richness and abundance of floral resources on restored landfill sites were not found to be significantly different from those on reference sites and the flower-visiting insect assemblages were similar in terms of species-richness and abundance. Interaction structures were examined and whilst the plant-insect assemblages had few species in common, both showed similar levels of nestedness and connectance. The differences in the species but similarity in the functioning of these assemblages emphasise the importance of examining interaction structures within a functional approach to the evaluation of restoration. There are 2,200 landfill sites in England and Wales covering some 28,000 ha, and this study highlights that their restoration can potentially provide an important resource for the conservation of pollinating insects and the services that they provide for both natural and agricultural plants.

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12

Morandin, Lora A. "Wild bees and agroecosystems /". Burnaby B.C. : Simon Fraser University, 2005. http://ir.lib.sfu.ca/handle/1892/2386.

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Thesis (Ph.D.) - Simon Fraser University, 2005.
Theses ( Dept. of Biological Sciences) / Simon Fraser University. Includes bibliographical references. Also issued in digital format and available on the World Wide Web.

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13

Erenler, Hilary E. "The diversity of flower-visiting insects in the gardens of English country houses". Thesis, University of Northampton, 2013. http://nectar.northampton.ac.uk/8857/.

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14

Bataw, Ali A. M. "Pollination ecology of cultivated and wild raspberry (Rubus idaeus) and the behaviour of visiting insects". Thesis, University of St Andrews, 1996. http://hdl.handle.net/10023/14205.

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Floral morphology and anthesis were studied in commercial and in wild populations of raspberry (Rubus idaeus). Young flowers offered both nectar and pollen, but medium and old flowers offered nectar only, in diminishing quantity. All the three types had similar ageing patterns and diurnal patterns of nectar secretion, but they differed significantly in the nectar standing crop. Variation in nectar secretion rates within the raspberry cultivars was examined; Glen Moy produced more nectar per flower, and more flowers per meter, than Glen Prosen and wild raspberry flowers. There was significant daily variation in secretion rate, individual flowers in all cultivars showing variable rates of secretion even on the same branch. Time of sampling, effects of insect visitors, flower age and weather conditions all showed significant relationships to nectar availability. The three raspberry types have in common certain insect species as visitors, the most abundant being bumble bees (Bombus lapidarius, B. lucorum, B. terrestris, B. pratorum and B. pascuorum). Apis mellifera, Andrena species and hover flies. Bumble bees were responsible for about 60% of all visits, with honey bees, Andrena and hover flies making up most the remaining visits. Bombus species were more abundant through the particular observation days and through the different seasons, and they were present at almost all times of observations irrespective of climatic conditions in the studied area. The foraging behaviour and activity patterns, pollen loads and pollinating efficiency of the Bombus spp., Apis and Andrena spp. were analysed in relation to plant phenology, anthesis and dehiscence and to climatic variables. All bees had substantial pollen deposited on their bodies during visits, though few specifically collected it. Bombus species were found to strongly select young flowers, especially early in the morning when pollen was most abundant, while Apis and Andrena species visited unselectively. Bumble bees also foraged over substantially longer periods of the day, and in poorer weather, and they visited more flowers per minute than Apis and Andrena species. Bombus species also carried more pollen grains on their bodies than Apis and Andrena species, and deposited more pollen on raspberry stigmas; and because they foraged over longer range, they transferred pollen grains for longer distance than Apis mellifera. The flight directionality of Bombus, Apis and Andrena species among the flowers of Glen Moy and Glen Prosen was analysed. Pollen flow was also studied using fluorescent dyes, in field experiments during 1993 and 1994. Bombus and Apis transferred dye particles (pollen mimics) to different extents in different directions in the field. All the three visitors showed a strong tendency to move in the south-north direction (the direction of the raspberry rows); this would lead to increase in the gene flow within the same row in the presence of pollen carry-over. Pollen was carried up to 60m by Bombus species and 35m by honey bees. The work presented in this thesis provides evidence that (at least in Scotland) bumble bees are likely to be more important as pollinators of raspberries than other visitors. Reason why Bombus may be the preferred insect pollinators in wild and cultivated areas are discussed.

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15

Puterbaugh, Mary Norris. "Alpine plant-ant interactions /". free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841329.

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16

Keshlaf, Marwan M. "An assessment of honeybee foraging activity and pollination efficacy in Australian Bt cotton". Thesis, View thesis, 2008. http://handle.uws.edu.au:8081/1959.7/38265.

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Cotton is a high-value commercial crop in Australia. Although cotton is largely self-pollinating, previous researchers have reported that honeybees, Apis mellifera, can assist in cross-pollination and contribute to improved yield. Until recently, use of bees in cotton had, however, been greatly limited by excessive use of pesticides to control arthropod pests. With the widespread use of transgenic (Bt) cotton varieties and the associated reduction in pesticide use, I decided to investigate the role and importance of honeybees in Bt cotton, under Australian conditions. I conducted two major field trials at Narrabri, in the centre of one of Australia’s major cotton-growing areas, in the 2005-6 and 2006-7 seasons. In the first trial, I particularly assessed methods of manipulating honeybee colonies by feeding pollen supplements of pollen/soybean patties, and by restricting pollen influx by the fitting of 30% efficient pollen traps. I aimed to test whether either of these strategies increased honeybee flight activity and, thus, increased foraging on cotton flowers. My results showed that although supplementary feeding increased bee flight activity and brood production, it did not increase pollen collection on cotton. Pollen traps initially reduced flight activity. They also reduced the amount of pollen stored in colonies, slowed down brood rearing activity, and honey production. However, they did not contribute to increased pollen collection in cotton. In the second trial, I spent more time investigating honeybee behaviour in cotton as well as assessing the effect of providing flowering cotton plants with access to honeybees for different time periods (e.g. 25 d, 15 d, 0 d). In this year, I used double the hive stocking rate of (16 colonies / ha) than in the previous year, because in 2005-6 I observed few bees in cotton flowers. I also conducted a preliminary investigation to assess whether there was any gene flow over a 16 m distance from Bt cotton to conventional cotton, in the presence of a relatively high honeybee population. Both of my field experiments showed that honeybees significantly increased cotton yield via increased boll set, mean weight of bolls, number of seeds / boll, and weight of lint / boll. It was obvious that cotton flowers, and particularly cotton pollen, were not attractive to honeybees, and this was also reflected in the low proportion (5.3% w/w) of pollen from cotton collected in the pollen traps. However, flower visitation rate was generally above the 0.5% level regarded as optimal for cross-pollination in cotton, and this was reflected in increased yield parameters. I recorded a gene flow of 1.7 % from Bollgard®II cotton to conventional cotton, over a distance of 16 m. This is much higher than had previously been reported for Australia, and may have been a result of high honeybee numbers in the vicinity, associated with my managed hives. In an attempt to attract more honeybees to cotton flowers, I conducted an investigation where I applied synthetic Queen Mandibular Pheromone (QMP) (Fruit Boost®) at two rates, 50 QEQ and 500 QEQ / ha, and for two applications, 2 d apart. Neither rate of QMP increased the level of bee visitation to flowers, either on the day of application or the subsequent day. There was also no increase in boll set or yield in plants treated with QMP. My observations of honeybee behaviour in cotton brought some interesting findings. First, honeybees totally ignored extra floral nectaries. Second, most flower-visiting honeybees collected nectar, but the overwhelming majority of them (84%) collected floral nectar from outside flowers: this meant these bees did not contribute to pollination. Those nectar gatherers which entered flowers did contribute to pollination. However, they were observed to exhibit rejection of cotton pollen by scraping pollen grains from their body and discarding them, prior to returning to their hives. Pollen gatherers collected only small, loose pellets from cotton. SEM studies showed that cotton pollen grains were the largest of all pollen commonly collected by bees in my investigations, and that they also had large spines. It is likely that these characteristics make cotton pollen unattractive to honeybees. Another possible reason for the unattractiveness of cotton flowers was the presence of pollen beetles, Carpophilus aterrimus, in them. I conducted a series of studies to determine the role of pollen beetles in pollination of cotton. I found that they did not contribute to pollination at low levels; at high populations they damaged flowers (with ≥ 10 beetles / flower, no flowers set bolls); and that honeybees, when given the choice, avoid flowers with pollen beetles. Because the insecticide fipronil was commonly used in Australian cotton at flowering time, and because I had some experience of its toxic effects against honeybees in my field investigations, I conducted a series of laboratory and potted plant bioassays, using young worker bees. The studies confirmed its highly toxic nature. I recorded an acute dermal LD50 of 1.9 ng / bee, and an acute oral LC50 of 0.62 ppm. Fipronil’s residual toxicity also remained high for an extended period in both laboratory and potted plant trials. For example, when applied to cotton leaves in weather-exposed potted cotton plants, it took 25 d and 20 d for full and half recommended rates of fipronil, respectively, to become non- toxic to honeybees. I had previously investigated whether a shorter period of exposure of cotton plants to honeybees would contribute adequately to increased yield, and concluded that a 10 d window within a 25 d flowering period would contribute 55% of the increase in total weight of bolls contributable to honeybee pollination, but only 36% of the increase in weight of lint. Given the highly residual activity of fipronil I recorded, the only opportunity for an insecticide-free period during flowering would be at its commencement. I concluded that, while there is evidence that honeybees can contribute to increased cotton yield in Bt cotton in Australia, this is unlikely with the continued use of fipronil at flowering.

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17

Howpage, Daya. "Pollination biology of kiwifruit : influence of honey bees, Apis melllifera L, pollen parents and pistil structure /". Richmond, N.S.W. : Centre for Horticulture and Plant Sciences, University of Western Sydney, Hawkesbury, 1999. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030509.153106/index.html.

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18

Lombardi, Giorgio Colombo. "Variation in breeding systems, floral morphology and nectar properties in three co-occurring Erica species with contrasting pollination syndromes". Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1018567.

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The genus Erica is the most species rich in the Cape Floristic Kingdom, yet there are limited data on the various flower-pollinator interactions and breeding systems for the majority of these species. Until recently research has focussed on predictive floral traits, including flower shape, length of corolla and corolla opening to identify likely pollinators in this genus. Field observations provide an empirical test of such predictions. This study investigated three species of Erica and compared their pollination and breeding systems and floral biology. Research, including field experiments and pollinator observations was undertaken in the Vogelgat Private Nature Reserve, Maanschynkop Nature Reserve and Boskloof farm in the vicinity of Hermanus in the Western Cape Province of South Africa. Field observations were conducted to determine what flower- visitor interactions occurred, while nectar volumes and sugar concentrations were measured to determine the value of the reward to the different visitors. Selective exclusion and breeding system experiments were carried out to determine whether these Erica species were capable of autonomous self-fertilization or whether they are pollinator dependent for breeding success. The unusual morphology of Erica lanuginosa suggested rodent-pollination. Field observations, including photographs of visits to plants in the field, the presence of pollen in scat sample and selective exclusion and breeding system experiments identified rodents, primarily Acomys subspinosus to be the primary pollinator. Long-proboscid flies of the family Nemestrinidae were found, on the basis of field observations to be responsible for pollination of the endemic Erica aristata. This was supported by with nectar volume and sugar concentration samples which are consistent with other long-proboscid fly-pollinated plant species. Selective exclusion and breeding system experiments undertaken confirmed that Erica aristata required a pollinator to set seed. Observations and breeding trials revealed bird-pollination in Erica sessiliflora. Nectar volume and sugar concentrations in Erica sessiliflora were in line with other sunbird-pollinated plant species, providing the necessary rewards for sunbirds visiting this species. Specialised pollination by single pollinators was found in all three species and results from breeding system experiments show that out-crossing is important. Further research into pollinator-flower interactions in the genus Erica is necessary, not least to understand more fully the conservation importance of specific pollinators.

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19

Coombs, Gareth. "Ecology and degree of specialization of South African milkweeds with diverse pollination systems". Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1003758.

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Like orchids, the complexity of flowers found in asclepiads (Asclepiadoideae, Apocynaceae) and the fact that pollen is presented as pollinaria, offers excellent opportunities to study various aspects of plant-pollinator interactions. In this thesis I investigated two broad themes: ecological aspects of the pollination biology of hymenopteran and fly-pollinated asclepiads as well as the degree of specialization to certain pollinators in these species. Colonizing plants often reproduce through self-pollination, or have highly generalized pollination systems, or both. These characteristics facilitate establishment in small founding populations and generates the prediction that reproductive success should be independent of population size in these species. Chapter one examines the pollination biology of Gomphocarpus physocarpus, an indigenous, weedy species and investigates the relationship between reproductive success and population size. In this species, there is no evidence of an Allee effect and reproductive success is not correlated with population size. In addition G. physocarpus is not capable of self-pollination, suggesting it is completely reliant on pollinators for seed set. The lack of a relationship between pollination success and population size is therefore likely explained by the generalized wasp pollination system of this species. Several milkweeds are invasive outside of their native ranges. Invasive species either need to co-opt native pollinators in order to reproduce or reduce their reliance on pollinators through having the ability to self-pollinate. Co-opting native pollinators is expected to be easier in species that have generalized pollination systems, alternatively species with specialized flower morphologies need to rely on similar functional groups of pollinators to be present within the invaded range. Chapter two investigates the pollination biology and pollination success of the invasive milkweed, Araujia sericifera, and finds that in South Africa, this species is visited mainly by native honeybees and nocturnal moths. Moths however contribute little to pollen removal, and deposition. Based on the apparent morphological mismatch between the flower of A. sericifera and native honeybees, I propose that the native pollinators of this species are likely to be larger Hymenoptera (e.g. Bumblebees). Data from a breeding system study, indicated that this species is not capable of automatic self-pollination, but could set fruit from geitonogamous self-pollinations pointing to the importance of native pollinators for successful reproduction. The pollinaria of milkweeds can accumulate on pollinators to form pollen masses large enough to physically interfere with the foraging behaviour of pollinating insects. In chapter three I describe the pollination biology of Cynanchum ellipticum and find that this species is mainly pollinated by honeybees although this species is visited by several other members of Hymenoptera, Lepidoptera and Diptera. Due to the structure of the pollinaria, these chain together relatively efficiently and frequently form large pollinarium loads on the mouthparts of honeybees. However there is little evidence that these pollinarium loads influence the foraging times of pollinators and only a few individual honeybees exhibited longer foraging times and most honeybees were unaffected by the presence of large pollinarium loads. Within the genus Cynanchum there is large variation in the gynostegium structure that may influence the pattern of pollinarium loading on pollinators as well as pollen reception as shown in chapter three. In Chapter four, the pollination biology of Cynanchum obtusifolium is examined, and like that of C. ellipticum, this species is visited by a wide diversity of pollinators but honeybees appear to be the primary pollinators. More importantly this species is shown to be andromonoecious and produces two morphologically different flower types, that may be distinguished based on differences in the gynostegium structure. These two types of flower could mainly be distinguished by the length of the anther wings. I found that flowers with short anther wings function as male flowers by only exporting- and rarely receiving pollinia. Flowers with longer anther wings function as hermaphrodite flowers and can both export and receive pollinia. The ratio of male to hermaphrodite flowers varied at different times during the flowering season, but preliminary data suggested that this was not related to levels of pollination success. The genera Stapelia and Ceropegia are well known for their intricate floral adaptations that mimic the brood and feeding substrates of pollinating flies. Despite several studies that have documented the various adaptations to fly pollination in different species, there is a lack of natural history studies documenting different flower visitors, pollen loads and long term levels of pollination success in these species. In Chapter six I document the pollination biology of Ceropegia ampliata by documenting different pollinators and quantifying average levels of pollination success and the nectar reward. I also experimentally manipulated the trapping hairs of this species to determine whether trapping hairs influence average levels of pollen export and receipt. I show that Ceropegia ampliata is pollinated by a generalist guild of flies (mainly Tachinidae, Sarcophagidae, Muscidae and Lauxaniidae) and produces minute quantities of relatively dilute nectar as a reward. Pollination success was generally low in this species and increases periodically suggesting that the abundance of pollinators is patchy. I found that flowers with trapping hairs that had already wilted had higher levels of pollinarium removal than flowers with erect hairs, however experimentally removing the hairs had no significant effect on pollen export and receipt. In Chapter seven, I document the pollinators, pollen loads and long term levels of pollination success in Stapelia hirsuta var. bayllissi, a rare sapromyiophilous stapeliad. I find that, in contrast to C. ampliata, this species was specialized to pollination by small flies of the family Anthomyiidae. Similar to the results from Chapter seven, I find that long term levels of pollination success were typically low but could increase periodically, although such increases were generally unpredictable. There are currently very few records documenting pollinator interactions in the Periplocoideae. Many species within this subfamily exhibit open-access flowers suggestive of pollination by short-tongued insects. I investigated the pollination biology of Chlorocyathus lobulata, a rare species with a highly localized distribution. I aimed to determine the pollinators, average levels of pollination success and demography of this species in order to determine whether this rare species is suffering from the collapse of a highly specialized pollinator mutualism. I also quantified the high incidence of flower herbivory caused by larvae of the moth, Bocchoris onychinalis. I find that C. lobulata has a highly generalized fly pollination system and average levels of pollination success suggested that a large proportion of flowers had pollen removed and deposited suggesting that this species is not experiencing pollination failure. The large numbers of juveniles present also indicated that recruitment is taking place.

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20

Sjöström, Sofia. "Fördelning av vilda pollinatörer med och utan närvaro av honungsbin i Västernorrland". Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-187362.

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Abstract (sommario):

My study focuses on how the pollination frequence for wild insect pollinators was influenced by the presence of honey bees. Man made beehives, with their thousands of honey bees, can potentially affect wild insect pollinators within 3 km radius. Several studies indicate that this competition will be disadvantageous for wild insect pollinators. The study at hand was conducted in boreal areas of North Swedens southern coastal region. In each area studied, the frequency of pollinators, wild as well as domesticated, was counted in close proximity to beehives and at reference areas, distanced more than 3 kilometres from nearest hive. The reults are somewhat startling, but not statistically significant. In five of the six sites, the wild pollinators were more numerous with honey bees present.

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21

Keshlaf, Marwan M. "An assessment of honeybee foraging activity and pollination efficacy in Australian Bt cotton". View thesis, 2008. http://handle.uws.edu.au:8081/1959.7/38265.

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Thesis (Ph.D.)--University of Western Sydney, 2008.
A thesis submitted to the University of Western Sydney, College of Health and Science, Centre for Plant and Food Science, in fulfilment of the requirements for the degree of Doctor of Philosophy. Includes bibliography.

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22

MAHMOOD, AHMED NOORI. "THE EFFECT OF HONEY BEE POLLINATION ON THE SEED QUANTITY AND QUALITY OF CULTIVATED GUAYULE PARTHENIUM ARGENTATUM GRAY". Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184080.

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Guayule (Parthenium argentatum Gray) is one of two major plants in the world grown for natural rubber and therefore, is of potential importance to the U.S. One area of research interest relates to methods of enhancing production of viable seeds. Therefore, studies were conducted in 1984, 1985, and 1986, in Tucson, Arizona to determine the effect of honey bee pollination on: seed set; seed weight; total seed yield; percentage of seed germination; yield and percentage of rubber and resin content. This experiment involved four guayule cultivars and four pollination treatments: plants caged with bees; plants caged without bees; plants open-pollinated; and plants individually covered with Delnet bags. All four cultivars responded positively to honey bee pollination. Plots with bees produced at least 195% more seeds than plots from which bees were excluded. However, there were no qualitative differences in the seed weights between the treatments. The percentage of seed germination from plots serviced by bees was significantly greater (65%) than from plots without bees (50%). Highest seed germination rates were obtained when seeds were collected in May (80%) and September (76%). June, July, and August seed collections resulted in lower seed germination rates (40%, 26%, and 63%, respectively). The plots in which bees were present gave a higher rubber yield (323 kg/ha) than plots without bees (255 kg/ha). However, there were no quantitative differences in the percentage of resin content between the treatments. These studies demonstrated that (1) honey bees can increase seed yield, seed germination, and rubber content in guayule, and (2) seeds produced during summer months had poorer germination rates and lower yields.

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23

Howpage, Daya. "Pollination biology of kiwifruit : influence of honey bees, Apis mellifera L, pollen parents and pistil structure". Thesis, Richmond, N.S.W. : Centre for Horticulture and Plant Sciences, University of Western Sydney, Hawkesbury, 1999. http://handle.uws.edu.au:8081/1959.7/338.

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The importance of European honey bees in improving fruit set, yield and fruit weight of kiwifruit on the central east coast of Australia was investigated. Field investigations were carried out using different bee saturations and different types of male pollen parents. These investigations confirmed the importance of honey bees in kiwifruit fruit set, yield and fruit weight. However, the results suggested that increasing bee activity alone may not increase pollination of kiwifruit by honey bees. Many factors need to be understood before introducing bees into the orchard. Bees were more effective during the early part of the flowering period, and bee activity varied according to the sex of the vine, planting design and the time of day. The type of male pollen parents also influenced fruit size and quality. Flowers pollinated by different pollen parents were assessed for pollen tube growth and histochemical changes. The resulting fruit were also examined for weight and seed numbers. Honey bees play the major role in the size and yield of kiwifruit, but the design of male vines, their age and type of male pollen may also contribute. The kiwifruit pistil also possesses important features that can be considered as adaptations to insect pollination.

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24

Feltham, Hannah. "Maximising a mutualism : sustainable bumblebee management to improve crop pollination". Thesis, University of Stirling, 2015. http://hdl.handle.net/1893/21917.

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Over 80% of wild angiosperms are reliant upon animal pollination for fruit and seed set and bees and other insects provide a vital pollination service to around a third of the crops we produce. Habitat loss, climate change and disease spread all threaten pollinator populations, with local declines and range contractions in honeybees and bumblebees leading to concerns that crop production may suffer as a result of pollinator shortages. Whilst agriculture and wildlife are often presented as being at odds with one another, the relationship between farmers growing pollination dependent crops, and the bees and insects that service them could be mutualistic. Flowering crops planted by farmers can provide an important source of forage to wild bees, whilst in return wild bees can contribute to ensuring farmers achieve adequate yields of marketable crops. The potential of this mutualistic relationship can be maximised by farmers by adopting management practices that reduce harm to, and enhance the wellbeing of, the wild bees around their farm. A group of common pesticides (neonicotinoids) used by farmers have recently been linked to pollinator ill health. Sub-lethal effects resulting from exposure to the neonicotinoid imidacloprid have been reported in honeybees and bumblebees, with bumblebee reproductive success found to diminish as a result of exposure to field realistic doses of this agrochemical. Here, the mechanism behind the reduced queen production in bumblebee colonies is suggested, with bees exposed to imidacloprid showing reduced efficiency in foraging for pollen. Farmers dependent upon pollinating insects for crop production can opt to avoid the use of pesticides known to harm these insects, however future studies are needed to identify safer alternatives that can be use in their place. Farmers can choose to increase the number of bees at their farms by utilising domesticated honeybees and purchasing commercially reared bumblebees. The use of these pollinators can ensure a minimum number of bees in the vicinity of a crop, and facilitate the production of crops at times when wild bee numbers are low. Concerns have been raised, however, regarding the use of commercially reared bees, mostly in regard to pathogen and parasite transmission, but also in respect to the possibility of outcompeting native species. Here the frequency and severity of attacks on commercial Bombus terrestris colonies, by the wax moth, an understudied bumblebee pest, are examined. Wax moths were found to infest almost half of the bumblebee nests deployed at fruit farms, with around a third of infestations resulting in nest destruction. Farmers investing in commercial bees will want to reduce the impact of harmful pests that may result in a reduced pollination service being delivered. Wax moth infestation rates at the study farms using commercial bees were high and the potential of a ‘spill- back’ effect on wild bees was examined. No evidence was found to suggest that nests in close proximity to these farms were any more or less likely to suffer from an attack than nests situated further away. Nest size was found to be the most significant predictor of an infestation, with larger nests more prone to wax moth attacks. Whilst farmers can utilise domesticated and commercially reared bees, relying on one source of pollination is inherently risky, and the most robust service will likely be provided by a range of pollinators. As well as reducing the use of chemicals known to harm beneficial insects, farmers can improve the habitat around their farms to help encourage and sustain wild pollinator populations. Sowing flower strips has been found to increase the abundance and diversity of pollinating insects, however, studies linking the use of these strips to crop production are lacking. Here we demonstrate for the first time that sowing small flower strips, adjacent to strawberry crops serviced by both wild and managed bees, can increase the overall number of pollinators foraging on the crop. This thesis contributes to our understanding of the implications of farm management decisions on pollinator health. It provides experimentally based evidence to guide farmers in making informed decisions regarding the future of crop pollination services and highlights the need for an integrated approach to managing pollination services for sustainability.

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25

Young, Laura May. "Masting and insect pollination in the dioecious alpine herb Aciphylla : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Biological Science in the University of Canterbury /". Thesis, University of Canterbury. Biological Sciences, 2006. http://hdl.handle.net/10092/1345.

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Abstract (sommario):

Aciphylla species (wild spaniard/speargrass) are an iconic component of the Australasian high country flora, but their reproductive system is enigmatic. They are insect-pollinated dioecious mast seeders (synchronous highly variable seed production), which seems maladaptive. The resource supply to pollinators is highly variable, yet dioecious plants are dependent on pollinators, and dioecious masting requires male and female plants to flower synchronously. Floral display in Aciphylla is relatively large, with tall inflorescences bearing thousands of flowers, suggesting that plants would not have the resources to produce such large stalks every year. But why do they have such huge inflorescences in the first place? I tested whether pollinator attraction is providing an economy of scale which favours intermittent production of very large inflorescences, by manipulating floral display size during a high-flowering year and measuring insect visitation rates and seed set (female reproductive success). Using space-for-time substitution and selective removal of male inflorescences, I also tested whether female seed set was affected by distance to flowering male plants (i.e. changes in local pollen availability) to see if flowering asynchrony would reduce pollination success. Bags were used to exclude pollination by insects and test for wind pollination, and hand pollination was done to test for pollen limitation. Insect surveys suggest that Aciphylla has a generalist pollination system (to avoid satiating a specialist pollinator during 'mast' years'). Male inflorescences received significantly more visits than females, and some seeds were set inside bags (although only 20-30%), suggesting wind pollination may occur at low levels. Seed set rate was higher for taller inflorescences with greater flowering length in A. aurea but tall inflorescences with excess flowers led to a decrease in seed set rates in A. scott-thomsonii. Hand pollination significantly increased seed set rates although these effects were not as large as expected (e.g. 10% increases from natural to hand-pollinated inflorescences were typical). There was no evidence for resource limitation in any species. Female plants in dense flowering populations had higher seed set rates, and individual floral display size in females was particularly important when females were 'isolated' from males. Insect visitation rates were generally higher on inflorescences with a larger floral display, suggesting that display size is important for pollinator attraction. Overall, these results suggest that the pollinator-attraction benefits of such a large floral display (at both the plant and population level) are possibly providing an economy of scale, although the relative effects are small.

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26

Greenfield, Cassandra Joyce. "Low Fruit Set, Pollen Limitation and the Roles of Birds and Insects in Pollination of Native New Zealand Plants". Thesis, University of Canterbury. Biological Sciences, 2010. http://hdl.handle.net/10092/5182.

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Pollination and fruit set of four species of native New Zealand flowering plant species were examined through two field seasons. Bird exclusion, pollinator exclusion, natural and supplemental pollination treatments were initiated on individuals of Cordyline australis (Cabbage tree), Phormium tenax (Flax), Kunzea ericoides (Kanuka), and Pseudopanax arboreus (Five-finger). The species differed in the self-compatibility as well as in their floral syndrome. No species showed any evidence of pollen limitation, and two species. K. ericoides and P. arboreus set fruit from more than 70% of their flowers. The response of fruit set to treatment in C. australis varied from season to season, with birds appearing important to pollination in the first but not the second field season, while birds were important in pollination across both seasons for P. tenax. K. ericoides was resilient to treatment, setting high fruit set in every treatment, compared to P. arboreus which set high fruit set when pollinators had access, but low when all pollinators were excluded. No trends relating to fruit set or PLI and self-compatibility or floral syndrome were found. That there was no evidence of pollen limitation for any species, despite variation in fruit set from some treatments, indicates that these species are performing well and not at risk of decreased population size due to pollen limitation.

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27

Auffray, Thomas. "Etude des interactions chimiques entre les espèces cultivées d'Elaeis et les insectes pollinisateurs". Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT074.

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Le palmier à huile africain Elaeis guineensis Jacqu. (Arecales : Arecaceae) est une plante tropicale d’intérêt économique et la première source mondiale d’huile végétale. La production d’huile dépend de la pollinisation par des charançons du genre Elaeidobius (Coleoptera : Curculionidae). Ces insectes sont impliqués dans une relation mutualiste spécialisée avec leur plante-hôte : ils se développent au dépend des inflorescences mâles qu’ils détectent par le biais des odeurs émises durant l’anthèse, tandis que les inflorescences femelles sont pollinisées en mimant les odeurs mâles. Une maladie mortelle sévissant en Amérique du sud et qui touche l’E. guineensis a contribué au développement de variétés commerciales d’hybrides interspécifiques, résultat du croisement entre E. guineensis et le palmier à huile sud-américain Elaeis oleifera (Knuth) Cortés. Mais ces hybrides s’avèrent naturellement mal pollinisées et nécessitent l’intervention d’une pollinisation assistée couteuse et contraignante. Cette thèse part de l’hypothèse que la communication chimique qui permet la rencontre entre les deux espèces de palmiers et leurs pollinisateurs respectifs est déficiente chez les hybrides.L’objectif principal de cette thèse a été d’étudier le fonctionnement du système de pollinisation des deux espèces de palmiers afin de comprendre pourquoi les hybrides sont mal pollinisés. L’étude a été conduite dans une plantation commerciale en Equateur, dans laquelle coexistent les deux espèces E. guineensis et E. oleifera avec leur insecte pollinisateur respectif, le charançon africain Elaeidobius kamerunicus Faust. et le charançon sud-américain Grasidius hybridus O’Brien & Beserra (Coleoptera : Curculionidae) et des palmiers hybrides interspécifiques. En utilisant des techniques de piégeages et l’échantillonnages des odeurs florales, nos résultats ont montré le système de pollinisation des deux espèces de palmier est basé sur l’émission d’un signal chimique spécifique et une duperie olfactive, renforcée par un phénomène de thermogénèse. Les deux insectes sont attirés en faible proportion sur les hybrides, qui possèdent une composition chimique intermédiaire à celle des espèces parentales. Des tests physiologiques et comportementaux ont permis d’identifier les composés organiques volatils clés responsables de l’attraction des insectes pollinisateurs.Ce travail devrait contribuer à apporter des connaissances théoriques sur le système de pollinisation du palmier à huile, et permettre d’élaborer des méthodes pratiques de gestion des pollinisateurs afin de réduire les coûts en pollinisation assistée
The African oil palm Elaeis guineensis Jacqu. (Arecales: Arecaceae) is a tropical plant of economic interest and the world's leading source of vegetable oil. Oil production depends on pollination by weevils of the genus Elaeidobius (Coleoptera: Curculionidae). These insects are involved in a specialized mutualist relationship with the host plant: they develop at the expense of the male inflorescences they detect through the odors emitted during the anthesis, while the female inflorescences are pollinated by mimicking the male odors. E. guineensis is affected by a lethal disease in South America that leads to the development of commercial varieties of interspecific hybrids, resulting from artificial crossing between E. guineensis and the South American oil palm Elaeis oleifera (Knuth) Cortés. However, the natural pollination of these hybrids is inadequate and require the intervention of a costly assisted pollination. This thesis hypothesizes that the chemical communication underlying the successful encountering between each oil palm species and their respective pollinators is deficient in hybrid palms.The main objective of this work was to study the functioning of the pollination system for both oil palm species to understand why natural pollination in hybrids is inefficient. The study was conducted in a commercial plantation in Ecuador, including the two species E. guineensis and E. oleifera present with their respective pollinating insects, the African weevil Elaeidobius kamerunicus Faust. and the South American weevil Grasidius hybridus O'Brien & Beserra (Coleoptera: Curculionidae), as well as interspecific hybrid palms. Using techniques of trapping and sampling of floral odors, our results showed the pollination system of both species of palm is based on the emission of a specific chemical signal and an olfactory deception, reinforced by a phenomenon of thermogenesis. The two insects are attracted in a small proportion to hybrid palms, which have an intermediate chemical composition compare to parent species. Physiological and behavioral tests permit the identification of the key volatile organic compounds responsible for pollinator attraction.This work should contribute to theoretical knowledge about the oil palm pollination system and the development of practical methods for pollinator management to reduce costs in assisted pollination

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28

Gess, Sarah Kathleen. "Ecology and natural history of the Masarid wasps of the world with an assessment of their role as pollinators in southern Africa (Hymenoptera : Vespoidea : Masaridae)". Thesis, Rhodes University, 1993. http://hdl.handle.net/10962/d1005354.

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Abstract (sommario):

The worldwide knowledge of the ecology and natural history of the masarid wasps, those wasps which bee-like provision their nest cells with pollen and nectar, is synthesized and discussed putting into context the investigations concerning nesting and flower visiting by southern African masarids conducted by the present author. Masarids are found mostly to favour warm to hot areas with relatively low rainfall and open scrubby vegetation. At the generic level the masarids of the Nearctic, Neotropical and Australian regions are distinct from each other and from those of the Palaearctic and Afrotropical regions combined. No species are shared between regions. Southern Africa is apparently the area of greatest species diversity. In this region, at least, there is a high incidence of narrow endemism. Masarids are associated with a relatively small range of plant families. Where sufficient records are available distinct major preferences are shown between zoogeographical regions. Relatedness of plant preferences between zoogeographical regions is apparent when relatedness of plant taxa is considered. Within a region there is marked overlap in masarid generic preferences for flower families. At the specific level there is marked oligolecty and narrow polylecty. The majority of nesting studies indicate that nest construction, egg laying and provisioning are performed by a single female per nest, however, nest sharing has been alledged for two species. No parasitic masarids have been recorded. Egg laying precedes provisioning. Mass provisioning is the rule. According to species, nests are sited in the ground, in non-friable soil or friable soil, in earthen vertical banks, on stones or on plants. Seven nest types are defined. Three bonding agents, water, nectar and self-generated silk are used. Masarids are evaluated as potential pollinators of their forage plants in southern Africa. The "masarid pollination syndrome", though less broad is shown to fall within that designated melittophily. The case studies considered make it clear that, whereas the masarids visiting some flower groups are members of a guild of potential pollinators, the masarids visiting others are probably their most important pollinators. Increasing land utilization is shown to threaten the existence of narrowly endmic masarid species.

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29

Ellis, Ciaran R. "Valuing wild pollinators for sustainable crop production". Thesis, University of Stirling, 2014. http://hdl.handle.net/1893/22327.

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Abstract (sommario):

This thesis looks at the role of wild pollinators in providing services to crops. Two data chapters (2 and 3) are accompanied by a modelling chapter (4) which build on the findings of the field studies. The thesis ends with an overview of the trends in pollinator populations and how these relate to the needs of farmers in the UK (chap-ter 5). It is often assumed that commercial pollinators are appropriate substitutes of wild pollinators on farms; however this view neglects the differing roles that particular pollinator taxa might play in providing pollination services. For example, crops with a long growing system may require multiple pollinators to ensure pollination throughout the season. Strawberries in Scotland have an extremely long growing season, flowering from April to August. Chapter 2 presents a study showing season-al complementarity between different pollinating taxa across strawberry farms in Scotland. Pollinators of strawberries also differed in their responses to weather pa-rameters indicating that preserving multiple pollinator taxa could ensure yields un-der different weather scenarios. The requirements of a long-growing season and ad-verse weather may be specific to strawberry production in Scotland, but the valua-tion of multiple taxa can be generalised to systems with differing needs, and also to different ecosystem services. Wild bees are not only valuable for providing complementary services to commercial pollinators, but are also valuable in the longer term as it is unknown whether com-mercial pollinators will be available in the future. There are threats to the supply of honeybees which have already triggered price rises; such supply shocks could force farmers to leave production or to seek other ways of providing pollination, including supporting wild pollinators. However farm management pressures, in particular pes-ticide use, could threaten the ability of wild pollinators to continue to support crop production. The interplay of pesticides and pollination is discussed in chapter 3 and 4. Chapter 3 presents an experiment undertaken on soft-fruit farms which had and had not used the neonicotinoid, thiacloprid, and shows that nests exposed to thia-cloprid had higher worker mortality, and lower male production than those at con-trol farms. This has implications both for pollination services now, as worker mor-tality will reduce the number of bees visiting farms, and also for the maintenance of future pollination services through decreased reproductive capacity of exposed nests. Chapter 4 uses a theoretical model to link pesticide use and habitat use to pollina-tion services, and shows that the use of commercial pollinators could mask the de-cline in wild populations, making local extinctions more likely. Chapter 5 sets out the status and extent of pollinators in the UK, along with popu-lation trends, trends in habitat and trends in pesticide use to provide an overview of how well pollination services are likely to meet the ongoing needs of crop farmers.

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30

Du, Toit Adriaan Pieter. "The pollination ecology of commercial sunflower (Helianthus annuus L.) in South Africa with special reference to the honeybee (Apis mellifera L.)". Diss., University of Pretoria, 1988. http://hdl.handle.net/2263/26786.

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Please read the abstract (Summary) in the section, 09summary and aknowledgements, of this document
Dissertation (MSc (Entomology))--University of Pretoria, 1988.
Zoology and Entomology
MSc
unrestricted

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31

Nelson, Jason M. "The Roles of Natural and Semi-Natural Habitat in the Provisioning of Biodiversity and Ecosystem Services of Beneficial Insects in Agricultural Landscapes". Miami University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=miami1344485293.

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32

Oliveira, Rafael Macedo de. "Importância da vegetação espontânea na polinização de pimenta, Capsicum frutescens". Universidade Federal de Viçosa, 2014. http://locus.ufv.br/handle/123456789/3997.

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Made available in DSpace on 2015-03-26T13:30:53Z (GMT). No. of bitstreams: 1 texto completo.pdf: 858304 bytes, checksum: da35f09db97f5331375c2dc2fd32de89 (MD5) Previous issue date: 2014-02-14
Conselho Nacional de Desenvolvimento Científico e Tecnológico
In most Brazilian regions a landscape of patches of native vegetation is found in an array of productive systems. This has caused a decrease in pollinator diversity and consequently the production of various crops. This work was initially studied the stigmatic receptivity of chilli pepper, Capsicum frutescens and the importance of pollination in the production (Chapter 1). Subsequently, the main pollinators of chili, the importance of spontaneous vegetation in the abundance of floral visitors and production of chilli pepper (Chapter 2) was studied. The experiments lasting flower and stigmatic receptivity were conducted in the laboratory of Entomology EPAMIG with 30 buds. Have the experiment to evaluate the importance of pollination in the production was performed in Oratorios/MG , in which 896 flower buds were marked to compose the two treatments , and restricted free pollination . Finally experiments of importance of spontaneous vegetation attract pollinators and production of chilli pepper were conducted in the municipalities of Oratorios/MG in six plants composed of 100 experimental sites, three free spontaneous vegetation and three containing spontaneous vegetation in edge and the line between the cultivation of pepper and Piranga/MG which had four of eight experimental areas free of spontaneous vegetation and the other four had the presence of spontaneous vegetation at the edge of cultivation and leading. The stigmatic receptivity occurred on the day of anthesis of 9 to 12 hours. The main floral visitors were bees, Tetragonisca angustula being the only species considered common in the environment. The diversity of floral visitors was higher in areas with pepper and without spontaneous vegetation. However, the area with natural vegetation present in one of the edges of the crop had greater abundance of floral visitors, showing that spontaneous vegetation is important for attracting pollinators. The proceeds of fruits pollinated flowers had greater mass than fruits of restricted pollination. The areas surrounded with spontaneous vegetation had a higher production of pepper compared with areas without spontaneous vegetation. Therefore, the spontaneous vegetation is important for higher abundance of pollinators and increased production of pepper.
Na maioria das regiões brasileiras é encontrada uma paisagem de fragmentos de vegetação nativa em uma matriz de sistemas produtivos. Isso tem ocasionado uma diminuição na diversidade de polinizadores e consequentemente da produção de diversas culturas. Neste trabalho, no capítulo 1 foi estudada a duração das flores e receptividade estigmática de pimenta-malagueta Capsicum frutescens, e a importância da polinização na produção. No capítulo 2, foram estudados os principais visitantes florais de pimenta-malagueta, a importância da vegetação espontânea na abundância de visitantes florais e na produção de frutos. Os experimentos de duração da flor e de receptividade estigmática foram realizados no laboratório de Entomologia da EPAMIG avaliando-se 30 botões florais. Para avaliar a importância da polinização na produção foi realizado um experimento em Oratórios/MG. Foram marcados 896 botões florais para compor os tratamentos de polinização livre e restrita. Os experimentos de importância da vegetação espontânea na atração de polinizadores e produção de pimenta-malagueta foram realizados em Oratórios/MG em três áreas experimentais compostas de 100 plantas livres de vegetação espontânea e outras três áreas também com 100 plantas, porém com vegetação espontânea na borda e na entrelinha do cultivo de pimenta e em Piranga/MG em quatro áreas experimentais livres de vegetação espontânea e em quatro com vegetação espontânea na borda do cultivo e na entrelinha. A receptividade estigmática ocorreu no dia da antese de 9 às 12 h. Os principais visitantes florais foram abelhas, sendo Tetragonisca angustula a única espécie comum no ambiente. A diversidade de visitantes florais foi maior na área com pimenta sem vegetação espontânea. No entanto, a área com vegetação espontânea em uma das bordas do cultivo teve maior abundância de visitantes florais. Os frutos advindos de flores polinizadas tiveram maior massa que frutos de polinização restrita. Nas áreas rodeadas com vegetação espontânea observou-se produção superior de pimenta comparado com as áreas sem vegetação espontânea. Conclui-se que a vegetação espontânea é importante para obter maior abundância de polinizadores e maior produção de pimenta.

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33

Davila, Yvonne Caroline. "Pollination ecology of Trachymene incisa (Apiaceae): Understanding generalised plant-pollinator systems". Thesis, The University of Sydney, 2006. http://hdl.handle.net/2123/1896.

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Abstract (sommario):

A renewed focus on generalised pollinator systems has inspired a conceptual framework which highlights that spatial and temporal interactions among plants and their assemblage of pollinators can vary across the individual, population, regional and species levels. Pollination is clearly a dynamic interaction, varying in the number and interdependence of participants and the strength of the outcome of the interaction. Therefore, the role of variation in pollination is fundamental for understanding ecological dynamics of plant populations and is a major factor in the evolution and maintenance of generalised and specialised pollination systems. My study centred on these basic concepts by addressing the following questions: (1) How variable are pollinators in a generalised pollination system? To what degree do insect visitation rates and assemblage composition vary spatially among populations and temporally among flowering seasons? (2) How does variation in pollinators affect plant reproductive success? I chose to do this using a model system, Trachymene incisa subsp. incisa (Apiaceae), which is a widespread Australian herbaceous species with simple white flowers grouped into umbels that attract a high diversity of insect visitors. The Apiaceae are considered to be highly generalist in terms of pollination, due to their simple and uniform floral display and easily accessible floral rewards. Three populations of T. incisa located between 70 km and 210 km apart were studied over 2-3 years. The few studies investigating spatial and temporal variation simultaneously over geographic and yearly/seasonal scales indicate that there is a trend for more spatial than temporal variation in pollinators of generalist-pollinated plants. My study showed both spatial and temporal variation in assemblage composition among all populations and variation in insect visitation rates, in the form of a significant population by year interaction. However, removing ants from the analyses to restrict the assemblage to flying insects and the most likely pollinators, resulted in a significant difference in overall visitation rate between years but no difference in assemblage composition between the Myall Lakes and Tomago populations. These results indicate more temporal than spatial variation in the flying insect visitor assemblage of T. incisa. Foraging behaviour provides another source of variation in plant-pollinator interactions. Trachymene incisa exhibits umbels that function as either male or female at any one time and offer different floral rewards in each phase. For successful pollination, pollinators must visit both male and female umbels during a foraging trip. Insects showed both preferences and non-preferences for umbel phases in natural patches where the gender ratio was male biased. In contrast, insects showed no bias in visitation during a foraging trip or in time spent foraging on male and female umbels in experimental arrays where the gender ratio was equal. Pollinator assemblages consisting of a mixture of different pollinator types coupled with temporal variation in the assemblages of populations among years maintains generalisation at the population/local level. In addition, spatial variation in assemblages among populations maintains generalisation at the species level. Fire alters pollination in T. incisa by shifting the flowering season and reducing the abundance of flying insects. Therefore, fire plays an important role in maintaining spatial and temporal variation in this fire-prone system. Although insect pollinators are important in determining the mating opportunities of 90% of flowering plant species worldwide, few studies have looked at the effects of variation in pollinator assemblages on plant reproductive success and mating. In T. incisa, high insect visitation rates do not guarantee high plant reproductive success, indicating that the quality of visit is more important than the rate of visitation. This is shown by comparing the Agnes Banks and Myall Lakes populations in 2003: Agnes Banks received the highest visitation rate from an assemblage dominated by ants but produced the lowest reproductive output, and Myall Lakes received the lowest visitation rate by an assemblage dominated by a native bee and produced the highest seedling emergence. Interestingly, populations with different assemblage composition can produce similar percentage seed set per umbel. However, similar percentage seed set did not result in similar percentage seedling emergence. Differences among years in reproductive output (total seed production) were due to differences in umbel production (reproductive effort) and proportion of umbels with seeds, and not seed set per umbel. Trachymene incisa is self-compatible and suffers weak to intermediate levels of inbreeding depression through early stages of the life cycle when seeds are self-pollinated and biparentally inbred. Floral phenology, in the form of synchronous protandry, plays an important role in avoiding self-pollination within umbels and reducing the chance of geitonogamous pollination between umbels on the same plant. Although pollinators can increase the rate of inbreeding in T. incisa by foraging on both male and female phase umbels on the same plant or closely related plants, most consecutive insect movements were between plants not located adjacent to each other. This indicates that inbreeding is mostly avoided and that T. incisa is a predominantly outcrossing species, although further genetic analyses are required to confirm this hypothesis. A new conceptual understanding has emerged from the key empirical results in the study of this model generalised pollination system. The large differences among populations and between years indicate that populations are not equally serviced by pollinators and are not equally generalist. Insect visitation rates varied significantly throughout the day, highlighting that sampling of pollinators at one time will result in an inaccurate estimate and usually underestimate the degree of generalisation. The visitor assemblage is not equivalent to the pollinator assemblage, although non-pollinating floral visitors are likely to influence the overall effectiveness of the pollinator assemblage. Given the high degree of variation in both the number of pollinator species and number of pollinator types, I have constructed a model which includes the degree of ecological and functional specialisation of a plant species on pollinators and the variation encountered across different levels of plant organisation. This model describes the ecological or current state of plant species and their pollinators, as well as presenting the patterns of generalisation across a range of populations, which is critical for understanding the evolution and maintenance of the system. In-depth examination of pollination systems is required in order to understand the range of strategies utilised by plants and their pollinators, and I advocate a complete floral visitor assemblage approach to future studies in pollination ecology. In particular, future studies should focus on the role of introduced pollinators in altering generalised plant-pollinator systems and the contribution of non-pollinating floral visitors to pollinator assemblage effectiveness. Comparative studies involving plants with highly conserved floral displays, such as those in the genus Trachymene and in the Apiaceae, will be useful for investigating the dynamics of generalised pollination systems across a range of widespread and restricted species.

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34

Davila, Yvonne Caroline. "Pollination ecology of Trachymene incisa (Apiaceae): Understanding generalised plant-pollinator systems". University of Sydney, 2006. http://hdl.handle.net/2123/1896.

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Abstract (sommario):

Doctor of Philosophy (PhD)
A renewed focus on generalised pollinator systems has inspired a conceptual framework which highlights that spatial and temporal interactions among plants and their assemblage of pollinators can vary across the individual, population, regional and species levels. Pollination is clearly a dynamic interaction, varying in the number and interdependence of participants and the strength of the outcome of the interaction. Therefore, the role of variation in pollination is fundamental for understanding ecological dynamics of plant populations and is a major factor in the evolution and maintenance of generalised and specialised pollination systems. My study centred on these basic concepts by addressing the following questions: (1) How variable are pollinators in a generalised pollination system? To what degree do insect visitation rates and assemblage composition vary spatially among populations and temporally among flowering seasons? (2) How does variation in pollinators affect plant reproductive success? I chose to do this using a model system, Trachymene incisa subsp. incisa (Apiaceae), which is a widespread Australian herbaceous species with simple white flowers grouped into umbels that attract a high diversity of insect visitors. The Apiaceae are considered to be highly generalist in terms of pollination, due to their simple and uniform floral display and easily accessible floral rewards. Three populations of T. incisa located between 70 km and 210 km apart were studied over 2-3 years. The few studies investigating spatial and temporal variation simultaneously over geographic and yearly/seasonal scales indicate that there is a trend for more spatial than temporal variation in pollinators of generalist-pollinated plants. My study showed both spatial and temporal variation in assemblage composition among all populations and variation in insect visitation rates, in the form of a significant population by year interaction. However, removing ants from the analyses to restrict the assemblage to flying insects and the most likely pollinators, resulted in a significant difference in overall visitation rate between years but no difference in assemblage composition between the Myall Lakes and Tomago populations. These results indicate more temporal than spatial variation in the flying insect visitor assemblage of T. incisa. Foraging behaviour provides another source of variation in plant-pollinator interactions. Trachymene incisa exhibits umbels that function as either male or female at any one time and offer different floral rewards in each phase. For successful pollination, pollinators must visit both male and female umbels during a foraging trip. Insects showed both preferences and non-preferences for umbel phases in natural patches where the gender ratio was male biased. In contrast, insects showed no bias in visitation during a foraging trip or in time spent foraging on male and female umbels in experimental arrays where the gender ratio was equal. Pollinator assemblages consisting of a mixture of different pollinator types coupled with temporal variation in the assemblages of populations among years maintains generalisation at the population/local level. In addition, spatial variation in assemblages among populations maintains generalisation at the species level. Fire alters pollination in T. incisa by shifting the flowering season and reducing the abundance of flying insects. Therefore, fire plays an important role in maintaining spatial and temporal variation in this fire-prone system. Although insect pollinators are important in determining the mating opportunities of 90% of flowering plant species worldwide, few studies have looked at the effects of variation in pollinator assemblages on plant reproductive success and mating. In T. incisa, high insect visitation rates do not guarantee high plant reproductive success, indicating that the quality of visit is more important than the rate of visitation. This is shown by comparing the Agnes Banks and Myall Lakes populations in 2003: Agnes Banks received the highest visitation rate from an assemblage dominated by ants but produced the lowest reproductive output, and Myall Lakes received the lowest visitation rate by an assemblage dominated by a native bee and produced the highest seedling emergence. Interestingly, populations with different assemblage composition can produce similar percentage seed set per umbel. However, similar percentage seed set did not result in similar percentage seedling emergence. Differences among years in reproductive output (total seed production) were due to differences in umbel production (reproductive effort) and proportion of umbels with seeds, and not seed set per umbel. Trachymene incisa is self-compatible and suffers weak to intermediate levels of inbreeding depression through early stages of the life cycle when seeds are self-pollinated and biparentally inbred. Floral phenology, in the form of synchronous protandry, plays an important role in avoiding self-pollination within umbels and reducing the chance of geitonogamous pollination between umbels on the same plant. Although pollinators can increase the rate of inbreeding in T. incisa by foraging on both male and female phase umbels on the same plant or closely related plants, most consecutive insect movements were between plants not located adjacent to each other. This indicates that inbreeding is mostly avoided and that T. incisa is a predominantly outcrossing species, although further genetic analyses are required to confirm this hypothesis. A new conceptual understanding has emerged from the key empirical results in the study of this model generalised pollination system. The large differences among populations and between years indicate that populations are not equally serviced by pollinators and are not equally generalist. Insect visitation rates varied significantly throughout the day, highlighting that sampling of pollinators at one time will result in an inaccurate estimate and usually underestimate the degree of generalisation. The visitor assemblage is not equivalent to the pollinator assemblage, although non-pollinating floral visitors are likely to influence the overall effectiveness of the pollinator assemblage. Given the high degree of variation in both the number of pollinator species and number of pollinator types, I have constructed a model which includes the degree of ecological and functional specialisation of a plant species on pollinators and the variation encountered across different levels of plant organisation. This model describes the ecological or current state of plant species and their pollinators, as well as presenting the patterns of generalisation across a range of populations, which is critical for understanding the evolution and maintenance of the system. In-depth examination of pollination systems is required in order to understand the range of strategies utilised by plants and their pollinators, and I advocate a complete floral visitor assemblage approach to future studies in pollination ecology. In particular, future studies should focus on the role of introduced pollinators in altering generalised plant-pollinator systems and the contribution of non-pollinating floral visitors to pollinator assemblage effectiveness. Comparative studies involving plants with highly conserved floral displays, such as those in the genus Trachymene and in the Apiaceae, will be useful for investigating the dynamics of generalised pollination systems across a range of widespread and restricted species.

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35

Manley, Robyn Anna. "Emerging viral diseases of pollinating insects". Thesis, University of Exeter, 2017. http://hdl.handle.net/10871/29677.

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Abstract (sommario):

The risks posed by rapidly evolving RNA viruses to human and animal health are well recognized. Epidemics in managed and wildlife populations can lead to considerable economic and biodiversity losses. Yet, we lack understanding of the ecological and evolutionary factors that promote disease emergence. Host-switching viruses may be a particular threat to species important for human welfare, such as pollinating bees. Both honeybees and wild bumblebees have faced sharp declines in the last decades, with high winter mortality seen in honeybees. Infectious and emerging diseases are considered one of the key drivers of declines, acting in synergy with habitat loss and pesticide use. Here I focus on multihost viruses that pose a risk to wild bumblebees. I first identify the risk factors driving viral spillover and emergence from managed honeybees to wild bumblebees, by synthesising current data and literature. Biological factors (i.e. the nature of RNA viruses and ecology of social bees) play a clear role in increasing the risk of disease emergence, but anthropogenic factors (trade and transportation of commercial honeybees and bumblebees) creates the greatest risk of viral spillover to wild bees. Basic knowledge of the pathogenic effect of many common pollinator viruses on hosts other than A. mellifera is currently lacking, yet vital for understanding the wider impacts of infection at a population level. Here, I provide evidence that a common bumblebee virus, Slow bee paralysis virus (SBPV), reduces the longevity of Bombus terrestris under conditions of nutrition stress. The invasion of Varroa destructor as an ectoparasitic viral vector in European honeybees has dramatically altered viral dynamics in honeybees. I test how this specialist honeybee vector affects multi-host pathogens that can infect and be transmitted by both honeybees and wild bumblebees. I sampled across three host species (A. mellifera, B. terrestris and B. pascuorum) from Varroa-free and Varroa-present locations. Using a combination of molecular and phylogenetic techniques I find that this specialist honeybee vector increases the prevalence of four multi-host viruses (deformed wing virus (type A and B), SBPV and black queen cell virus) in sympatric wild bumblebees. Furthermore, wild bumblebees are currently experiencing a DWV epidemic driven by the presence of virus-vectoring Varroa in A. mellifera. Overall this thesis demonstrates that wild bumblebees are at high risk of viral disease emergence. My research adds to the ever-expanding body of evidence indicating that stronger disease controls on commercial bee operations are crucial to protect our wild bumblebees.

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36

Robinson, Samuel Victor Joseph. "Insect pollination and experimental warming in the High Arctic". Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46539.

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Abstract (sommario):

As climate change causes retreats in Arctic glaciers, it is important to understand the mechanics of growth and community change in Arctic plant communities. Arctic plants have been shown to respond to observed and experimental changes in temperature by altering their reproductive strategies, growth, and phenology. Researchers have used open-top chambers (OTCs) to experimentally alter the near-surface air temperatures of tundra plant communities over long periods of time, but these devices may exclude insect pollinators to flowers during crucial periods of pollen reception. Insect pollination in the context of OTCs and Arctic plants is therefore important to understand, but has been poorly researched. I altered pollination of Salix arctica, Dryas integrifolia, and Papaver radicatum inside and outside of OTCs in a High Arctic shrub community, and conducted targeted insect netting to understand the dynamics of the visiting insect community. I also conducted bowl trapping inside and outside of OTCs to gauge their effect on insect availability to receptive flowers. OTCs altered the timing of flowering in Arctic plants, and significantly reduced the availability of pollinators to available flowers. However, I found that while both warming and pollination can alter flower and seed production in the study species, pollination is largely independent of OTC warming. Early-flowering species have the potential to be most affected by OTC-induced insect exclusion. The most common visiting insects were flies of the families Syrphidae and Muscidae, with occasional bumblebees (Bombus polaris). Papaver radicatum was by far the most heavily-visited flower, and I showed that the Syrphidae visit the flower preferentially at low temperatures, likely for warmth as well as pollen. I discuss these results in context with the current literature on Arctic plant and insect communities, and make recommendations for future research.

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37

Osborn, Heather. "THE INTERACTION OF HERBIVORY AND POLLINATION". OpenSIUC, 2019. https://opensiuc.lib.siu.edu/dissertations/1705.

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Abstract (sommario):

The interaction of herbivory and pollination is not well understood. Both topics on their own have been studied thoroughly, yet their interaction has not. Until the 1990s, few studies attempted to explore how herbivory might affect pollination, and vice versa.

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38

Swan, M. C. "An investigation of pollen transfer by selected pollinating insects". Thesis, Swansea University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639143.

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Abstract (sommario):

Insect mediated pollen dispersal was studied in Althaea officinalis, Succisa pratensis, Chrysanthemum coronarium, Matricaria maritima and Matthiola sinuata using fluorescent dust as a pollen analogue or tracer. The species where chosen because of their different spectra of pollinators, so that the effects on pollen transfer of different behaviour patterns in different insect groups could be assessed. Pollinator behaviour was also studied by direct observation of insects foraging in both natural and artificial plant populations. Individual pollinators were marked in many cases, and both general behaviour patterns, and differences between individuals were studied. Evidence is presented to indicate that foraging insects generally move into the wind, and that pollen flow is therefore generally upwind. Also, most pollen transfers occur within a range of ten metres or often considerably less, although occasional movements to much greater distances are recorded. The behaviour patterns of various insect groups are discussed, with particular emphasis on comparing and contrasting bumblebees, butterflies, moths and hoverflies in terms of constancy, directionality and distance of flight. While many generalisations can be made, it becomes clear that it is also very important to understand that individuality can be significant. Thus, different individuals within a species can often exhibit a degree of constancy or discrimination. In some species this may result in discrimination by the population as a whole, while others may have a homogeneous overall behaviour pattern.

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39

Dicks, Lynn V. "The structure and functioning of flower-visiting insect communities on hay meadows". Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249064.

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40

Husman, Stephen H., e Michael J. Ottman. "Growing Alfalfa for Seed in Arizona". College of Agriculture, University of Arizona (Tucson, AZ), 2015. http://hdl.handle.net/10150/552951.

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Abstract (sommario):

Originally Published: 1999; Revised
3 pp.
Seed production for profitability is challenging. Cultural practices differ from those commonly used in forage production. This article outlines management recommendations that may help to accomplish profitable seed alfalfa yields.

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41

Matus, de la Parra Gutiérrez Nicolás. "The role of intraspecific competition between plants in a nursery pollination system". Bachelor's thesis, Pontificia Universidad Católica del Perú, 2021. http://hdl.handle.net/20.500.12404/20417.

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Abstract (sommario):

We present comments on an article published by Villacañas de Castro and Hoffmeister (2020). The authors studied a tritrophic system composed of a plant, its pollinating seed predator, and a parasitoid of the latter. Their concern was whether the parasitoid modifies the interaction between the plant and its pollinator-herbivore along the mutualism-antagonism gradient, but they reduced their question to how the parasitoid impacts plant fitness. After showing that the parasitoid increases seed output of the plant by decreasing the amount of seeds consumed by the pollinating seed predator, they tested whether seed output is a good proxy for plant fitness. They argue that it is not by showing that the increased seed density has a negative impact in survival probability and flower production, likely due to plant intraspecific competition. The work presented shows careful experimentation and interesting results, but we do not share some of their conclusions. Most importantly, we believe that the net effect of the parasitoid on the plant-herbivore interaction can’t be adequately investigated by focusing on individual plant fitness. Thus, we first suggest considering the number of surviving plants up to adulthood as a proxy for population performance to address this question. Using this proxy, we show that the increase in seed output due to the parasitoid is beneficial to the plant population until its carrying capacity is achieved. Next, using a population dynamics model, we show under which particular conditions the negative effect of intraspecific competition outweighs the positive effect of seed density increase (due to parasitoid’s defense). When these conditions don’t hold, the role of plant intraspecific competition is basically limited to the prevention of unbounded population growth, while the parasitoid’s net effect is an increase in the plant’s equilibrium density over its carrying capacity when interacting only with the pollinating seed predator, thus making the system more stable.
Trabajo de investigación

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42

Brand, Mariette Rieks. "Pollination ecosystem services to onion hybrid seed crops in South Africa". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86238.

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Abstract (sommario):

Thesis (PhD)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Insect pollination contributes in various degrees toward the production of a variety of agricultural crops that ensure diversity and nutritional value in the human diet. Although managed honeybees (Apis mellifera L.) are still the most economically valuable pollinators of monoculture crops cultivated globally, wild pollinator communities can contribute substantially toward crop pollination through pollination ecosystem services sourced from neighbouring natural habitats. Pollination ecosystem services are thus valuable and can motivate for the protection of natural ecosystems hosting diverse insect pollinator communities. F1 onion hybrid seed production is entirely dependent on high insect pollinator activity to ensure cross pollination, seed set and profitable seed yields. Data was collected on 18 onion hybrid seed crops grown in the semi‐arid Klein Karoo and southern Karoo regions of the Western Cape, South Africa. These two main production regions are located within the Succulent Karoo biome, recognized as a global biodiversity hotspot of especially high plant diversity. It is also habitat to the indigenous Cape honeybee (Apis mellifera capensis Esch.). Sites selected varied in the percentages of available natural habitat and managed honeybee hives stocking density. Diverse anthophile assemblages were sampled with pan traps within all the onion fields, regardless of the percentage of available natural habitat near the crop. Crop management practices significantly affected the diversity of anthophile species caught within onion fields, although less than 20% of this diversity was observed actually visiting onion flowers. The honeybee (managed and wild) was by far the most important pollinator because of its high visitation frequency and regular substantial onion pollen loads carried on their bodies. Honeybee visitation significantly increased onion hybrid seed yield, while anthophile diversity and non‐Apis visitation had no effect on seed yield. Neither managed hive density, nor percentage natural habitat were important in determining honeybee visitation or seed yield. Total annual rainfall was the only significant factor determining honeybee visitation. Secondary factors caused by rainfall variability, such as wild flower abundance or soil moisture, may have significantly affected honeybee visitation. In addition, the positive correlation between honeybee visitation and the diversity of hand‐sampled insects from onion flowers; indicate that either or both onion varietal attractiveness and/or pollinator population size may have had significant effects on overall insect visitation. Honeybees showed marked discrimination between hybrid onion parental lines and preferred to forage on one or the other during single foraging trips. Hybrid onion parents differed significantly in nectar characteristics and onion flower scent which would encourage selective foraging through floral constancy. Interspecies interactions were insignificant in causing increased honeybee pollination because of the scarcity of non‐Apis visitors. Most farming practices are subjected to favourable environmental conditions for successful production. However, and especially in the South African context, the dependence of onion hybrid seed crops on insect pollination for successful yields, increase its reliance on natural ecosystem dynamics that may deliver abundant wild honeybee pollinators, or attract them away from the crops. Nevertheless, this dependence can be mitigated effectively by the use of managed honeybee colonies to supplement wild honeybee workers on the flowers.
AFRIKAANSE OPSOMMING: Insek bestuiwing dra in verskillende grade by tot die produksie van landbou gewasse wat variteit en voedingswaarde in die mens se dieet verseker. Al is die heuningby (Apis mellifera L.) steeds die waardevolste ekonomiese bestuiwer van verboude enkelgewasse, kan wilde bestuiwers wesenlik bydra tot gewasbestuiwing deur middel van ekosisteem dienste afkomstig van natuurlike habitatte. Bestuiwing ekosisteem dienste is daarom waardevol en kan dus die bewaring van natuurlike ekosisteme, wat diverse gemeenskappe huisves, regverdig. F1 basterui saadproduksie is totaal afhanklik van hoë insek‐bestuiwer aktiwiteit om kruisbestuiwing, saadvorming en winsgewende saadopbrengste te verseker. Data is ingesamel op 18 basterui saad aanplantings in die half‐droë Klein Karoo en suid‐Karoo streke van die Weskaap, Suid‐Afrika. Hierdie twee hoof produksie streke is geleë binne die Sukkulente Karoo bioom wat erken word as ŉ globale biodiversiteits “hotspot” met hoë plant diversiteit. Dit is ook die habitat van die inheemse Kaapse heuningby (Apis mellifera capensis Esch.). Aanplantings is gekies om verskillende grade van beskikbare natuurlike habitat en bestuurde heuningby korf digthede te verteenwoordig. Diverse versamelings blom‐besoekers is versamel met water‐wippe in al die aanplantings, ongeag die persentasie natuurlike habitat beskikbaar by elke aanplanting. Gewas bestuurspraktyke het die diversiteit van blombesoekers betekenisvol beïnvloed. Tog is minder as 20% van hierdie diversiteit as aktiewe besoekers op die uiekoppe waargeneem. Heuningbye (bestuur of wild) was oorwegend die belangrikste bestuiwers as gevolg van hoë besoek frekwensies en wesenlike ladings uiestuifmeel op hulle liggame. Heuningby besoeke het saadopbrengs betekenisvol verhoog, maar blom‐besoeker diversiteit en nie‐Apis besoeke het geen effek op saadopbrengs gehad nie. Bestuurde korf digtheid en persentasie natuurlike habitat was nie belangrik in die bepaling van heuningby besoeke of basterui saadopbrengste nie. Totale jaarlikse reënval was die enigste betekenisvolle faktor wat heuningby besoeke bepaal het. Sekondêre faktore wat versoorsaak word deur reënval veranderlikheid, soos veldblom volopheid of grondvog, kon betekenisvolle effekte op die aantal heuningby besoeke gehad het. Bykomend, dui die positiewe korrelasie tussen heuningby besoeke en die diversiteit van hand‐versamelde insekte vanaf die uiekoppe op die moontlike betekenisvolle effek van elk of beide basterui variteit aantreklikheid en/of bestuiwer populasie grote op algehele insek besoeke. Heuningbye het noemenswaardige diskriminasie getoon tussen die basterui ouerlyne en het verkies om op een of die ander te wei tydens enkele weidingstogte. Basterui ouerlyne het betekenisvol verskil in nektar eienskappe en blomgeur wat die selektiewe weiding van heuningbye, toegepas deur blomkonstantheid, sal aanmoedig. Tussen‐spesie interaksies was onbetekenisvol in die verhoging van heuningby bestuiwing omdat nie‐Apis besoekers baie skaars was. Meeste boerdery praktyke is onderhewig aan gunstige omgewings toestande vir suksesvolle produksie. Maar, en veral in die Suid‐Afrikaanse konteks, omdat basterui saad aanplantings afhanklik is van insek bestuiwing vir suksesvolle opbrengste, word daar meer staat gemaak op natuurlike ekosisteem dinamika wat volop wilde heuningby bestuiwers kan voorsien, of selfs bestuiwers van die aanplanting kan weg lok. Nietemin, hierdie afhanklikheid kan effektief verlaag word deur die gebruik van bestuurde heuningby kolonies om die aantal wilde heuningby werkers op die blomme aan te vul.

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43

Howpage, Daya, of Western Sydney Hawkesbury University, Faculty of Environmental Management and Agriculture e Centre for Horticulture and Plant Sciences. "Pollination biology of kiwifruit : influence of honey bees, Apis mellifera L, pollen parents and pistil structure". THESIS_FEMA_HPS_Howpage_D.xml, 1999. http://handle.uws.edu.au:8081/1959.7/338.

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Abstract (sommario):

The importance of European honey bees in improving fruit set, yield and fruit weight of kiwifruit on the central east coast of Australia was investigated. Field investigations were carried out using different bee saturations and different types of male pollen parents. These investigations confirmed the importance of honey bees in kiwifruit fruit set, yield and fruit weight. However, the results suggested that increasing bee activity alone may not increase pollination of kiwifruit by honey bees. Many factors need to be understood before introducing bees into the orchard. Bees were more effective during the early part of the flowering period, and bee activity varied according to the sex of the vine, planting design and the time of day. The type of male pollen parents also influenced fruit size and quality. Flowers pollinated by different pollen parents were assessed for pollen tube growth and histochemical changes. The resulting fruit were also examined for weight and seed numbers. Honey bees play the major role in the size and yield of kiwifruit, but the design of male vines, their age and type of male pollen may also contribute. The kiwifruit pistil also possesses important features that can be considered as adaptations to insect pollination.
Doctor of Philosophy (PhD)

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44

Araújo, Diogo Feliciano Dias. "A polinização de mirtilo (Vaccinium corymbosum L. var. Southern Highbush), uma cultura de clima temperado introduzida em ambiente tropical". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/59/59131/tde-06112018-101159/.

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Diversos aspectos vêm sendo estudados com relação à introdução de novas variedades de mirtilo no Brasil. A polinização de culturas tipicamente de clima temperado em clima tropical representa um enorme desafio para adaptação dessa cultura no país. Estudos relacionados à biologia básica da reprodução e ecologia da polinização envolvendo abelhas nas variedades do tipo Southern Highbush, ainda são inexistentes no Brasil e serão importantes para disseminação do cultivo. Levando-se em consideração que um dos aspectos determinantes dos efeitos de plantas exóticas nas comunidades nativas é a forma como interagem com a fauna, esse trabalho buscou identificar algumas variáveis relacionadas à polinização envolvidas no processo de produção comercial da cultura do mirtilo. Os objetivos do trabalho foram: compreender aspectos básicos relacionados ao sistema de polinização em quatro variedades do tipo Southern Highbush; identificar os requerimentos básicos de polinização; observar as abelhas presentes na área de produção e observar o comportamento de visita floral e a sobrevivência de abelhas sem ferrão de cinco espécies diferentes (Melipona quadrifasciata, Frieseomelitta varia, Scaptotrigona depilis, Tetragonisca angustula e Plebeia droryana) introduzidas em área de produção comercial de mirtilo. Observações diretas no campo foram realizadas para variáveis como formação de frutos expostos ou não a polinizadores, tamanho de flores, danos às flores por abelhas do gênero Trigona, entre outros. O florescimento das quatro variedades na área de produção apresentou um comportamento muito semelhante com pequenas variações ao longo do período de observação. Iniciou por volta da última semana de fevereiro com menos de 1% das plantas floridas, e uma predominância da variedade Emerald no início do florescimento. O pico de florescimento ocorreu nos meses de março a julho, com final de florescimento bastante determinado em setembro. O período de antese das flores foi observado para todas as quatro variedades, das 07:00h até às 09:00h da manhã. Após esse período a flor permanecia aberta até sua senescência, cerca de seis a sete dias depois. Os estigmas das quatro variedades permaneceram receptivos desde a abertura da flor até o sexto dia após a antese. A viabilidade polínica foi verificada desde antese da flor até o momento de senescência da mesma. Um percentual de 89% dos grãos pólen contabilizados, nas quatro variedades avaliadas, apresentou-se viável até o quarto dia de vida da flor. Abelhas da espécie Frieseomelitta varia, Tetragonisca angustula e Plebeia droryana estiveram presentes em todas as observações. Já abelhas do gênero Melipona quadrifasciata e Scaptotrigona depilis não foram observadas visitando as flores de mirtilo. Os resultados mostram que mesmo em um ambiente com uma intensidade grande de manejo fitossanitário as abelhas suportaram razoavelmente bem, com apenas uma ocorrência de mortalidade de colônias. Os danos provocados por abelhas do gênero Trigona não foram severos e após a introdução de abelhas manejáveis, abelhas do gênero Trigona não foram mais observadas na área de produção. Concluímos que a cultura do mirtilo é amplamente beneficiada pela polinização cruzada e o manejo de determinados polinizadores nativos, além da abelha exótica Apis mellifera, contribui com o aumento da produtividade da cultura.
Several aspects have been studied in relation to the introduction of new blueberry varieties in Brazil. Pollination of crops typically temperate in tropical climate presents a huge challenge to adapt this crop in the country. Studies related to basic breeding biology and pollination ecology involving bees in Southern Highbush varieties are still non-existent in Brazil and will be important for dissemination of the crop. Taking into account that one of the determinant aspects of the effects of exotic plants in native communities is the way they interact with the fauna, this work sought to identify some variables related to the pollination involved in the commercial production process of the blueberry crop. The objectives of this work were: to understand basic aspects related to the pollination system in four Southern Highbush varieties; identify the basic pollination requirements; (Melipona quadrifasciata, Frieseomelitta varia, Scaptotrigona depilis, Tetragonisca angustula and Plebeia droryana) introduced into the commercial production area of blueberry . Direct observations in the field were performed for variables such as the formation of fruit exposed or not to pollinators, size of flowers, damage to flowers by bees of the genus Trigona, among others. The flowering of the four varieties in the production area showed a very similar behavior with small variations throughout the period of observation. It began around the last week of February with less than 1% of flowering plants, and a predominance of the \'Emerald\' variety at the beginning of flowering. The flowering peak occurred in the months of March to July, with a flowering end determined in September. The anthesis period of the flowers was observed for all four varieties, from 7:00 a.m. to 9:00 a.m. in the morning. After this period the flower remained open until its senescence, about six to seven days later. The stigmas of the four varieties remained receptive from the opening of the flower to the sixth day after the anthesis. The pollen viability was verified from before the flower until the moment of its senescence. A percentage of 89% of the pollen grains counted, in the four varieties evaluated, was viable until the fourth day of life of the flower. Bees of the species Frieseomelitta varia, Tetragonisca angustula and Plebeia droryana were present in all observations. Bees of the genus Melipona quadrifasciata and Scaptotrigona depilis were not observed were not observed visiting the blueberry flowers. The results show that even in an environment with a great intensity of phytosanitary management the bees supported reasonably well, with only one occurrence of colony mortality. The damage caused by bees of the genus Trigona was not severe and after the introduction of manageable bees, bees of the genus Trigona were no longer observed in the production area. We conclude that blueberry cultivation is widely benefited by cross - pollination and the management of certain native pollinators, in addition to the exotic bee Apis mellifera, contributes to the increase of crop productivity.

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Alcorn, Katrina Leanjka. "Pollinator behaviour and the evolutionary genetics of petal surface texture in the Solanaceae". Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648281.

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46

Sjödin, N. Erik. "Pollinating insect responses to grazing intensity, grassland characteristics and landscape complexity : behaviour, species diversity and composition /". Uppsala : Dept. of Ecology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200755.pdf.

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47

Yong, Kamuela E. "A mathematical model of the interactions between pollinators and their effects on pollination of almonds". Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/3020.

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Abstract (sommario):

California's almond industry, valued at $2.3 billion per year, depends on the pollinator services of honey bees, although pollination by other insects, mainly solitary wild bees, is being investigated as an alternative because of recent declines in the number of honey bee colonies. Our objective is to model the movements of honey bees and determine the conditions under which they will forage in less favorable areas of a tree and its surroundings when other pollinators are present. We hypothesize that foraging in less favorable areas leads to increased movement between trees and increased cross pollination between varieties which is required for successful nut production. We use the Shigesada-Kawasaki-Teramoto model (1979) which describes the density of two species in a two-dimensional environment of variable favorableness with respect to intrinsic diffusions and intra- and interspecific interactions of species. The model is applied to almond pollination by honey bees and other pollinators with environmental favorableness based on the distribution of flowers in trees. Using the spectral-Galerkin method in a rectangular domain, we numerically approximated the two-dimensional nonlinear parabolic partial differential system arising in the model. When cross-diffusion or interspecific effects of other pollinators was high, honey bees foraged in less favorable areas of the tree. High cross-diffusion also resulted in increased activity in honey bees in terms of accelerations, decelerations, and changes in direction, indicating rapid redistribution of densities to an equilibrium state. Empirical analysis of the number of honey bees and other visitors in two-minute intervals to almond trees shows a negative relationship, indicating cross-diffusion effects in nature with the potential to increase movement to a different tree with a more favorable environment, potentially increasing nut production.

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48

Ballantyne, Gavin. "Ants as flower visitors : floral ant-repellence and the impact of ant scent-marks on pollinator behaviour". Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2535.

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As flower visitors, ants rarely benefit a plant, commonly disrupting pollination by deterring other flower visitors, or stealing nectar. This thesis examines three aspects of ant-flower interactions, focusing on the occurrence of floral traits that prevent disruption of pollination and a novel means by which ants may influence pollinator behaviour. To assess which types of plant species possess ant-repelling floral traits I carried out a survey of 49 Neotropical plant species. Around a third of these species were repellent to the common generalist ant Camponotus novograndensis (Formicinae). This repellence was positively correlated with large nectar volumes within individual flowers. It appears that there has been selection for floral ant-repellence as a defence against ant thieves in plant species that invest in large volumes of nectar. In some cases these repellent traits were effective against a wide range of ant species. However, in no plant species were predacious ants particularly repelled, indicating that there may be little selective pressure on non-ant-plants to defend potential pollinators from aggressive ants. To investigate the importance of coevolution in determining the effectiveness of ant-repellents, a small but diverse range of Mediterranean plant species were tested with the invasive nectar thieving ant Linepithema humile (Dolichoderinae) and the native but non-nectar thieving ant Messor bouvieri (Myrmecinae). Responses of both ant species to floral traits were very similar. The ability of some plants to restrict access to ant species with which they have no evolutionary history may help to reduce the impact invasive species, as nectar thieves, have on plant-pollinator interactions. It is reported that flowers recently visited by bees and hoverflies may be rejected for a period of time by subsequent bee visitors through the detection of scent-marks. Nectar-thieving ants could potentially influence the foraging decisions of bees in a similar way if they come to associate ant trail pheromones or footprint hydrocarbons with poor reward levels. However, my empirical work found no differences were found in bee visitation behaviour between flowers of Digitalis pupurea (Plantaginaceae), Bupleurum fruticosum (Apiaceae) or Brassica juncea (Brassicaceae) that had been in contact with ants and control flowers. Ant-attendance at flowers of these species may not reduce reward levels sufficiently to make it worthwhile for bees to incorporate ant scent-marks into foraging decisions. Investigations like these into the interactions between ants, flowers and other flower visitors are essential if we hope to understand the part ants play in pollination ecology, and determine how ants have helped shape floral evolution.

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Arnold, Sarah Elizabeth Joan. "Flowers through insect eyes : the contribution of pollinator vision to the evolution of flower colour". Thesis, Queen Mary, University of London, 2010. http://qmro.qmul.ac.uk/xmlui/handle/123456789/622.

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Flowers’ colours are an essential element of their ability to attract visits from pollinators. However, the colours as they appear to human observers can differ substantially from their appearance to insect pollinators, and so it is essential to consider pollinator vision in any study of the ecology of flower colour. In this thesis I describe how I have overseen the development of an online database to provide accurate information on floral spectral reflectance measured without human observational bias. This resource allows a more accurate consideration of flower colours in future studies, and permits investigations of flower colours within and across habitats. Using the records in this database, I analysed flowers from two European habitats for spatial or temporal changes, modelling the colours according to insect visual perception. I discovered that the insect-colour composition of the plant communities does not change either along an altitudinal gradient or throughout the year. These novel and ecologically-relevant analyses contradict previous observational studies, but support the theory of a pollination “market” in which flowers compete for pollinator visitation. I then describe my experimental investigations into the visual capabilities of two pollinators and how this may relate to what colours of flowers they visit. Firstly I study the foraging behaviour of bees under spatially inconsistent illumination and how this impacts on their choice behaviour. I revealed patchy light can have measurable effects on bee foraging behaviour: they intentionally choose familiar over unfamiliar illumination, which may impact on the flowers they visit in complex natural environments. Secondly, I detail the new evidence for a red-sensitive photoreceptor in South African monkey beetles, a major pollinator in a habitat containing many longwavelength- reflecting flowers, which are not classically “attractive” to bees. Throughout this thesis, I explore how pollinator vision has shaped the evolution of flower colours in different contexts.

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50

Tudor, Emily Paige. "The Patterns and Processes of Insect Pollinator Re-assembly across a Post-mining Restoration Landscape". Thesis, Curtin University, 2021. http://hdl.handle.net/20.500.11937/83667.

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This thesis presents an integration of in situ field studies and ex situ laboratory experiments to provide a deeper insight into the patterns and processes underpinning the reassembly of insect pollinator communities in post-mining Jarrah Forest restoration. Overall, this research highlighted the value of early successional patches and suggests that the habitat selection of some endemic insect pollinators is driven largely by their thermal tolerance, energetic requirements, and ecophysiology.

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