Journal articles on the topic 'Generalist pollinators'
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1
Borkent, Christopher J., and Lawrence D. Harder. "Flies (Diptera) as pollinators of two dioecious plants: behaviour and implications for plant mating." Canadian Entomologist 139, no. 2 (April 2007): 235–46. http://dx.doi.org/10.4039/n05-087.
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AbstractWe consider the role of generalist Diptera in the pollination of two dioecious plant species, Clematis ligusticifolia Nutt. (Ranunculaceae) and Shepherdia canadensis (L.) Nutt. (Elaeagnaceae). In particular, we assess (i) whether or not generalist pollinators are unable to distinguish between the sexes of dioecious species and so visit the sexes at equivalent rates, and (ii) the number of flowers that generalist flies visit and revisit during a foraging bout, which would affect self-pollination if plants were hermaphroditic. We determined the visitation rate to each plant species during 10 min periods and recorded the number of flowers that individual pollinators visited and revisited per foraging bout. Diptera were the main pollinators, visiting both sexes at similar rates for both plant species. The main visitors to C. ligusticifolia were muscoid flies (small and large), Culicidae, and halictid bees. The number of flowers visited in this species varied with pollinator group, but groups did not differ in the frequency of revisits. Visitors to S. canadensis were primarily Syrphidae and Empididae. Neither the number of flowers visited nor the number of revisits differed between these two pollinator groups. The results for each plant species are discussed and contrasted, particularly with other studies of the behaviour of generalist and specialist pollinators. We compare the observed pollinator behaviours, and their implications for plant mating, with the various theories of the role of pollinators in the evolution of the dioecious breeding system in plants.
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Leal, Roberta Luisa Barbosa, Marina Muniz Moreira, Alessandra Ribeiro Pinto, Júlia de Oliveira Ferreira, Miguel Rodriguez-Girones, and Leandro Freitas. "Temporal changes in the most effective pollinator of a bromeliad pollinated by bees and hummingbirds." PeerJ 8 (March 25, 2020): e8836. http://dx.doi.org/10.7717/peerj.8836.
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A generalist pollination system may be characterized through the interaction of a plant species with two or more functional groups of pollinators. The spatiotemporal variation of the most effective pollinator is the factor most frequently advocated to explain the emergence and maintenance of generalist pollination systems. There are few studies merging variation in floral visitor assemblages and the efficacy of pollination by different functional groups. Thus, there are gaps in our knowledge about the variation in time of pollinator efficacy and frequency of generalist species. In this study, we evaluated the pollination efficacy of the floral visitors of Edmundoa lindenii (Bromeliaceae) and their frequency of visits across four reproductive events. We analyzed the frequency of the three groups of floral visitors (large bees, small bees, and hummingbirds) through focal observations in the reproductive events of 2015, 2016, 2017, and 2018. We evaluated the pollination efficacy (fecundity after one visit) through selective exposure treatments and the breeding system by manual pollinations. We tested if the reproductive success after natural pollination varied between the reproductive events and also calculated the pollen limitation index. E. lindenii is a self-incompatible and parthenocarpic species, requiring the action of pollinators for sexual reproduction. Hummingbirds had higher efficacy than large bees and small bees acted only as pollen larcenists. The relative frequency of the groups of floral visitors varied between the reproductive events. Pollen limitation has occurred only in the reproductive event of 2017, when visits by hummingbirds were scarce and reproductive success after natural pollination was the lowest. We conclude that hummingbirds and large bees were the main and the secondary pollinators of E. lindenii, respectively, and that temporal variations in the pollinator assemblages had effects on its reproductive success. Despite their lower pollination efficacy, large bees ensured seed set when hummingbirds failed. Thus, we provide evidence that variable pollination environments may favor generalization, even under differential effectiveness of pollinator groups if secondary pollinators provide reproductive assurance.
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Chesshire, Paige R., Lindsie M. McCabe, and Neil S. Cobb. "Variation in Plant–Pollinator Network Structure along the Elevational Gradient of the San Francisco Peaks, Arizona." Insects 12, no. 12 (November 26, 2021): 1060. http://dx.doi.org/10.3390/insects12121060.
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The structural patterns comprising bimodal pollination networks can help characterize plant–pollinator systems and the interactions that influence species distribution and diversity over time and space. We compare network organization of three plant–pollinator communities along the altitudinal gradient of the San Francisco Peaks in northern Arizona. We found that pollination networks become more nested, as well as exhibit lower overall network specialization, with increasing elevation. Greater weight of generalist pollinators at higher elevations of the San Francisco Peaks may result in plant–pollinator communities less vulnerable to future species loss due to changing climate or shifts in species distribution. We uncover the critical, more generalized pollinator species likely responsible for higher nestedness and stability at the higher elevation environment. The generalist species most important for network stability may be of the greatest interest for conservation efforts; preservation of the most important links in plant–pollinator networks may help secure the more specialized pollinators and maintain species redundancy in the face of ecological change, such as changing climate.
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Scott-Brown, Alison, and Hauke Koch. "New directions in pollinator research: diversity, conflict and response to global change." Emerging Topics in Life Sciences 4, no. 1 (June 18, 2020): 1–6. http://dx.doi.org/10.1042/etls20200123.
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Interactions between pollinators and their plant hosts are central to maintaining global biodiversity and ensuring our food security. In this special issue, we compile reviews that summarize existing knowledge and point out key outstanding research areas to understand and safeguard pollinators, pollinators–host plant interactions and the pollination ecosystem services they provide. The vast diversity of the pollinator–plant interactions that exists on this planet still remains poorly explored, with many being associations involving a specialist pollinator partner, although historically most focus has been given to generalist pollinators, such as the honeybee. Two areas highlighted here are the ecology and evolution of oligolectic bee species, and the often-neglected groups of pollinators that forage solely at night. Advances in automated detection technologies could offer potential and complementary solutions to the current shortfall in knowledge on interactions occurring between less well-documented plant–pollinator associations, by increasing the collection range and capacity of flower visitation data over space and time. Pollinator–host plant interactions can be affected by external biotic factors, with herbivores and pathogens playing particularly important roles. Such interactions can be disrupted by modifying plant volatile and reward chemistry, with possible effects on pollinator attraction and pollination success. Mechanisms which underpin interactions between plants and their pollinators also face many anthropogenic disturbances. Reviews in this issue discuss threats from parasites and climate change to pollinator populations and plant–pollinator networks, and suggest new ways to mitigate these threats. While the protection of existing plant–pollinator networks will be a crucial goal for conservation biology, more research is needed to understand how lost interactions in degraded habitats may be restored with mutual benefits to plants and pollinators.
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Nordström, Karin, Josefin Dahlbom, V. S. Pragadheesh, Suhrid Ghosh, Amadeus Olsson, Olga Dyakova, Shravanti Krishna Suresh, and Shannon B. Olsson. "In situ modeling of multimodal floral cues attracting wild pollinators across environments." Proceedings of the National Academy of Sciences 114, no. 50 (November 27, 2017): 13218–23. http://dx.doi.org/10.1073/pnas.1714414114.
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With more than 80% of flowering plant species specialized for animal pollination, understanding how wild pollinators utilize resources across environments can encourage efficient planting and maintenance strategies to maximize pollination and establish resilience in the face of environmental change. A fundamental question is how generalist pollinators recognize “flower objects” in vastly different ecologies and environments. On one hand, pollinators could employ a specific set of floral cues regardless of environment. Alternatively, wild pollinators could recognize an exclusive signature of cues unique to each environment or flower species. Hoverflies, which are found across the globe, are one of the most ecologically important alternative pollinators after bees and bumblebees. Here, we have exploited their cosmopolitan status to understand how wild pollinator preferences change across different continents. Without employing any a priori assumptions concerning the floral cues, we measured, predicted, and finally artificially recreated multimodal cues from individual flowers visited by hoverflies in three different environments (hemiboreal, alpine, and tropical) using a field-based methodology. We found that although “flower signatures” were unique for each environment, some multimodal lures were ubiquitously attractive, despite not carrying any reward, or resembling real flowers. While it was unexpected that cue combinations found in real flowers were not necessary, the robustness of our lures across insect species and ecologies could reflect a general strategy of resource identification for generalist pollinators. Our results provide insights into how cosmopolitan pollinators such as hoverflies identify flowers and offer specific ecologically based cues and strategies for attracting pollinators across diverse environments.
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Higuera-Díaz, Mónica, Jessamyn S. Manson, and Jocelyn C. Hall. "Pollination biology of Cleomella serrulata and Polanisia dodecandra in a protected natural prairie in southern Alberta, Canada." Botany 93, no. 11 (November 2015): 745–57. http://dx.doi.org/10.1139/cjb-2015-0084.
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Flowering plants that attract a diverse range of pollinators represent a generalist pollination system. Studying these plants provides valuable information about accessibility of floral resources to pollinators, which is particularly important in areas where scarcity of flowers limits pollinator populations. Here, we describe the flowering phenology, reproductive biology, and visitor community of Cleomella serrulata (Pursh) Roalson & J.C.Hall and Polanisia dodecandra (L.) DC., two native species with generalist pollination systems and limited distribution in Albertan prairies. Although their flowers are similar, they differ in traits such as petal colour, inflorescence size, and nectar display. Both species were facultatively cross-pollinated and exhibited nocturnal anthesis but differed in nectar production patterns. Cleomella serrulata produced highest nectar volume in the morning and highest sugar concentration at noon, while Polanisia dodecandra produced highest nectar volume before noon but sugar concentrations were higher at sunset. We observed 150 insect taxa visiting the plants, with Hymenoptera and Diptera as the most frequent visitors for Cleomella serrulata and Polanisia dodecandra, respectively. We recorded the first nocturnal flower visitors for Cleomella serrulata and the first record of Nysson plagiatus (Cresson) for Alberta. Both plant species present effective nectar and pollen resources for pollinators at the study sites and may be useful in the maintenance of native pollinators in at-risk prairie ecosystems.
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Staines, Morgan, Cathy Vo, Natalie Puiu, Sarah Hayes, Marika Tuiwawa, Mark I. Stevens, and Michael P. Schwarz. "Pollen larceny of the tropical weed Solanum torvum by a Fijian endemic halictine bee with implications for the spread of plants with specialized pollinator requirements." Journal of Tropical Ecology 33, no. 3 (May 2017): 183–87. http://dx.doi.org/10.1017/s0266467417000098.
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Abstract:The ability of plants to colonize new habitats is influenced by their dependence on effective pollinators. This can be very important for plants that require specialized pollinators, especially when they disperse to islands that have low pollinator diversity. One form of specialization involves plants that require buzz-pollination, where bees must vibrate poricidal anthers at frequencies that allow pollen to be released. Pollen larceny is a phenomenon where insects ‘steal’ pollen from flowers which usually results in reduced pollination, but in some cases there can be a small contribution to pollination. Here we report pollen larceny in an endemic Fijian halictine bee Homalictus fijiensis that steals pollen by chewing anthers of the invasive weed Solanum torvum, which is a pollen-only plant requiring buzz pollination. In over nine hours of observations at six sites where H. fijiensis visited S. torvum, it never attempted to locate nectaries, it never buzzed anthers, and instead chewed anther tips, indicating an adaptation to exploit nectarless flowers with poricidal anthers without buzz-pollination. Analyses of 30 pollen loads from H. fijiensis collected from S. torvum flowers indicate 27 of these contained S. torvum pollen, ranging from 1% to 99% of total pollen, indicating it is a pollen vector for this plant. Our findings support arguments that super-generalist pollinators in island ecosystems can promote the spread of invasive plants, but go further by indicating that super-generalist strategies can extend to plants with highly specialized pollinator requirements.
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Piacentini, Vítor de Queiroz, and Isabela Galarda Varassin. "Interaction network and the relationships between bromeliads and hummingbirds in an area of secondary Atlantic rain forest in southern Brazil." Journal of Tropical Ecology 23, no. 6 (October 29, 2007): 663–71. http://dx.doi.org/10.1017/s026646740700449x.
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The reciprocal importance of bromeliads and hummingbirds has been proposed for many years, even suggesting coevolution between these two groups. Nevertheless, data are lacking that allow a better test of the relationships involved. Here we investigate the relationship between bromeliads and hummingbirds in an area of secondary Atlantic rain forest in southern Brazil. The study examined the interactions among 12 species of bromeliad and 10 of hummingbird at Reserva Natural Salto Morato, Paraná state. The number of flowering species of bromeliad and the species richness and abundance of hummingbirds were quantified monthly between November 2004 and October 2005. Focal observations on each bromeliad species were made to determine the hummingbird visitors. Neither species richness nor abundance of hummingbirds were related to bromeliad phenology. Together with the monthly variation in visit frequency by a given pollinator to a given plant, these factors indicate a generalization in the use of bromeliads by hummingbirds and argue against tight coevolution. Ramphodon naevius and Thalurania glaucopis were the main pollinators in the community. Aechmea nudicaulis was the most generalist bromeliad species. The generalist species interacted with other generalists or with asymmetric specialists and there was no specialist–specialist interaction. This produced a strongly organized and nested matrix of interactions. This nestedness is similar to other plant-pollinators networks, supporting the hypothesis that the evolutionary relationship between bromeliads and hummingbirds is no stronger than that of other pollination networks.
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Ropars, Lise, Laurence Affre, Matthieu Aubert, Catherine Fernandez, Floriane Flacher, David Genoud, Frédéric Guiter, et al. "Pollinator Specific Richness and Their Interactions With Local Plant Species: 10 Years of Sampling in Mediterranean Habitats." Environmental Entomology 49, no. 4 (June 13, 2020): 947–55. http://dx.doi.org/10.1093/ee/nvaa061.
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Abstract In the context of global pollinator decline, little is known about the protection status and ecology of many species. This lack of knowledge is particularly important for Mediterranean protected areas that harbor diverse pollinator communities and are subject to considerable anthropogenic pressures. Calanques National Park (85 km2), which is located near Marseille (France), is dominated by Mediterranean low-vegetation habitats, such as phrygana and scrublands. These habitats offer favorable conditions for pollinator species due to the important amount of floral resources. Within a 10-yr period, we recorded bee (Hymenoptera: Apoidea: Anthophila), hover fly (Diptera: Syrphidae), and bee fly (Diptera: Bombyliidae) species and their interactions with the local flora through 10 field campaigns. We caught 250 pollinator species, including 192 bees, 38 hover flies, and 20 bee flies, for a total of 2,770 specimens. We recorded seven threatened bees (six near threatened and one endangered). Among the bee species, 47.9% were below-ground nesting species, and 54.7% were generalist species. Analysis of the pollination network showed that generalist and specialist pollinators do not share the same floral resources. The Cistaceae plant family (Malvales: Cistaceae) acted as a central node in the plant–pollinator network, interacting with 52 different pollinator species, which shows the importance of large open flowers that could be easily visited by both short and long-tongued pollinators in Mediterranean habitats. The occurrence of pollinator species and their ecological traits should strongly contribute to reinforcing the available information to provide or ameliorate the conservation statuses determined by IUCN Red List.
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Russell, Avery L., and Tia-Lynn Ashman. "Associative learning of flowers by generalist bumble bees can be mediated by microbes on the petals." Behavioral Ecology 30, no. 3 (February 6, 2019): 746–55. http://dx.doi.org/10.1093/beheco/arz011.
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Abstract Communication is often vital to the maintenance of mutualisms. In plant-pollinator mutualisms, plants signal pollinators via floral displays, composed of olfactory, visual, and other plant-derived cues. While plants are understood to be associated with microbes, only recently has the role of microbial (yeast and bacteria) inhabitants of flowers as intermediaries of plant-pollinator communication been recognized. Animals frequently use microbial cues to find resources, yet no study has examined whether microbes directly mediate learned and innate pollinator responses. Here, we asked whether microbes on the flower surface, independent of their modification of floral rewards, can mediate these key components of pollinator preference. In the field, we characterized flower and bumble bee microbial abundance, and in laboratory assays we tested whether bumble bees (Bombus impatiens) discriminated flowers on the basis of an experimental floral microbial community on the petals and whether microbe-derived chemicals were effective cues. Learning of microbial community cues was associative and reward context-dependent and mediated by microbial chemicals. Deconstructing the experimental microbial community showed bees innately avoided flowers with bacteria, but were undeterred by yeast. Microbial cues thus potentially facilitate dynamic communication between plants and pollinators such as bumble bees, especially as pollinator visitation can change flower microbiota. We suggest that the study of communication in mutualism generally would benefit by considering not only the multicellular eukaryote partners, but their microbial associates.
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Crichton, Arthur, Nikki Francis, Seamus Doherty, Marika Tuiwawa, Sarah Hayes, Mark I. Stevens, and Michael P. Schwarz. "Low endemic bee diversity and very wide host range in lowland Fiji: support for the pollinator super-generalist hypothesis in island biogeography." Pacific Conservation Biology 25, no. 2 (2019): 135. http://dx.doi.org/10.1071/pc18037.
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The success of invading plants in island ecosystems has often been inferred to result from ‘invader complexes’, where cointroduced plants and their specialist pollinators can reciprocally enhance each other’s spread. However, it has also been suggested that in islands with low pollinator diversity, those pollinators should evolve into super-generalists that may be able to pollinate a wide range of exotic plants, enabling the spread of exotic weeds. Fiji has a very depauperate endemic bee fauna and previous studies have suggested that its only lowland bee species, Homalictus fijiensis (Apoidea: Halictidae), has a very wide range of host plants. However, those studies only included a small number of endemic flowering plants. Our study expands observations of bee–flower interactions to explore host plant ranges of H. fijiensis and introduced bee species to include a wider variety of native and introduced plant species. We show that H. fijiensis does have a wider host range than introduced bees, including Apis mellifera (Apoidea: Apidae), and an ability to exploit extrafloral nectaries and poricidal anthers that are not utilised by the introduced bee species. Our results support the hypothesis that super-generalism can evolve in islands where pollinator diversity is low, and that this may make those islands susceptible to weed invasions.
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Mahy, Grégory, Jacques De Sloover, and Anne-Laure Jacquemart. "The generalist pollination system and reproductive success of Calluna vulgaris in the Upper Ardenne." Canadian Journal of Botany 76, no. 11 (November 1, 1998): 1843–51. http://dx.doi.org/10.1139/b98-133.
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Although specialist pollination systems are often thought to be the outcome of selection, wide evidence exists for generalization within plant-pollinator interactions. We studied the pollination system and reproductive success of Calluna vulgaris (L.) Hull over 3 years in an Upper Ardennes site in Belgium. A wide variety of insect visitors was recorded including Hymenoptera, Diptera, and Lepidoptera. Relative abundance of families and species of visitors varied markedly among years except for bees. Bumblebees and honeybees were the most efficient pollinators at the study site. Syrphid flies, mainly large ones, acted as important co-pollinators because of their high relative frequency. Calluna pollen was also dispersed by wind, and insect-exclusion experiments demonstrated that wind pollination contributed to reproductive success. Following open pollination, fruit set was high, ranging from 82.0 to 97.2% and independent of sampling location. Mean seed number per fruit was less than maximum potential seed number and varied strongly among sampling locations. We discuss this pollination system (generalist insect and wind) in terms of the ecological and geographical success of the species.Key words: Calluna vulgaris, pollinator visitation, insects, wind pollination, reproductive success.
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Faast, Renate, Lachlan Farrington, José M. Facelli, and Andrew D. Austin. "Bees and white spiders: unravelling the pollination syndrome of Caladenia rigida (Orchidaceae)." Australian Journal of Botany 57, no. 4 (2009): 315. http://dx.doi.org/10.1071/bt08135.
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Orchids of the genus Caladenia have been shown to utilise two quite different pollination strategies, namely species-specific sexual deception of thynnine wasps and a more generalist strategy attracting a larger spectrum of foraging insects. While baiting techniques have enabled the identification of numerous pollinators of sexually deceptive Caladenia, insects that pollinate food-advertising species have received little attention. The present study employed a multidisciplinary approach to better evaluate the pollination syndrome of the white spider orchid, Caladenia rigida R.S.Rogers, a species previously reported to utilise both food and sexual deception. This included the observation and capture of potential pollinators of C. rigida through direct observation, pantraps, Malaise traps and pollinator-baiting experiments, and the use of molecular techniques to identify orchid pollinia isolated from carrier insects. We describe a suite of generalist insects visiting and bearing pollinia from C. rigida. In addition, samples collected from the labellum and column of C. rigida contained sugars at levels comparable to those of a known nectar-producing orchid, Microtis parviflora R.Br. Potential osmophores in the clubs and calli stained positively with neutral red and although this character is often associated with sexual deception, we found no evidence for this secondary pollination syndrome in C. rigida. The present study is the first one to provide a detailed description of the pollinators and pollination syndrome of a non-sexually deceptive species within the genus Caladenia and the first report to provide evidence of nectar production by a species within this genus.
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Cerceau, Isabelle, Samuel Siriani-Oliveira, Ana Laura Dutra, Reisla Oliveira, and Clemens Schlindwein. "The cost of fidelity: foraging oligolectic bees gather huge amounts of pollen in a highly specialized cactus–pollinator association." Biological Journal of the Linnean Society 128, no. 1 (June 19, 2019): 30–43. http://dx.doi.org/10.1093/biolinnean/blz083.
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Abstract Plant–pollinator interactions vary along a specialization–generalization continuum. Advances in understanding the evolutionary and ecological consequences of different degrees of specialization depend on precise data on plant–pollinator interdependency. We studied the association of Parodia neohorstii (Cactaceae) and its bee pollinators focusing on pollinator foraging behaviour, flower functioning, female and male reproductive success, and pollen fate. Parodia neohorstii showed synchronized flower opening and pollen presentation but discontinuous blooming. The apparently generalized flowers partition pollen through thigmonastic stamen movements that function as a mechanical filter against generalist bees by restricting access to the major pollen reservoir to bees that show flower handling ‘know-how’, thereby favouring the oligolectic bee Arhysosage cactorum. This pollinator adjusted its pollen foraging to flower opening, removed pollen hurriedly, and promoted maximal fruit and seed set, which was minimal in its absence. Estimates of pollen fate revealed that a huge amount of pollen flows to specialized pollinators (86.5%), and only 0.9% reaches conspecific stigmas. The specialized interaction between P. neohorstii and Arhysosage cactorum, both threatened species, is efficient but fragile. Any environmental modification that causes a mismatch between the partners is likely to result in reproductive failure.
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Gómez, José María, Francisco Perfectti, and Christian Peter Klingenberg. "The role of pollinator diversity in the evolution of corolla-shape integration in a pollination-generalist plant clade." Philosophical Transactions of the Royal Society B: Biological Sciences 369, no. 1649 (August 19, 2014): 20130257. http://dx.doi.org/10.1098/rstb.2013.0257.
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Flowers of animal-pollinated plants are integrated structures shaped by the action of pollinator-mediated selection. It is widely assumed that pollination specialization increases the magnitude of floral integration. However, empirical evidence is still inconclusive. In this study, we explored the role of pollinator diversity in shaping the evolution of corolla-shape integration in Erysimum , a plant genus with generalized pollination systems. We quantified floral integration in Erysimum using geometric morphometrics and explored its evolution using phylogenetic comparative methods. Corolla-shape integration was low but significantly different from zero in all study species. Spatial autocorrelation and phylogenetic signal in corolla-shape integration were not detected. In addition, integration in Erysimum seems to have evolved in a way that is consistent with Brownian motion, but with frequent convergent evolution. Corolla-shape integration was negatively associated with the number of pollinators visiting the flowers of each Erysimum species. That is, it was lower in those species having a more generalized pollination system. This negative association may occur because the co-occurrence of many pollinators imposes conflicting selection and cancels out any consistent selection on specific floral traits, preventing the evolution of highly integrated flowers.
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Fontaine, Colin, Elisa Thébault, and Isabelle Dajoz. "Are insect pollinators more generalist than insect herbivores?" Proceedings of the Royal Society B: Biological Sciences 276, no. 1669 (June 10, 2009): 3027–33. http://dx.doi.org/10.1098/rspb.2009.0635.
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Della Rocca, Francesca, Arianna Tagliani, Pietro Milanesi, Matteo Barcella, and Silvia Paola Assini. "Contrasting Response of Mountain Plant-Pollinator Network to Fragmented Semi-Natural Grasslands." Land 12, no. 2 (January 28, 2023): 356. http://dx.doi.org/10.3390/land12020356.
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The majority of the world’s plants rely on animal pollinators for reproduction, making pollination a key ecosystem service for the maintenance of natural and cultivated plant communities. Mutual interactions between plants and pollinators, also called “plant-pollinator networks”, are becoming increasingly vulnerable due to the intensification of anthropogenic land use and climate change. Thus, due to the rapid decline of semi-natural grasslands in the Northern Apennines (Italy), we aimed at understanding how the fragmentation of these habitats, the spatial distribution, and the amount of semi- and natural areas surrounding them, could affect species diversity and plant-pollinator networks. Specifically, in the Northern Apennines, we monitored semi-natural grasslands belonging to the EU habitat type 6510 to evaluate the effect of fragmentation on plant and pollinator richness and on the plant-pollinator network. We carried out generalized linear models considering three taxonomical and six network descriptors as response variables and the combinations of grasslands size and isolation, as well as 10 other factors describing landscape composition as explanatory variables. We found a well-structured plant-pollinator network, characterized by a high diversity of both plants and pollinators, with mutual relations marginally specialized, highly affected by habitat fragmentation and the land use of surrounding grasslands. Moreover, large and neighboring patches increased pollinator richness and improved the overall network structure while the occurrence of meadows and shrubs around fragmented patches was important to ensure the continuity of floristic resources. Finally, extensive croplands and agricultural settlements significantly reduced plant and pollinator diversity, favoring generalist (probably invasive) species, which however increased the strength and stability of the network.
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Maharaj, Gyanpriya, and Godfrey Bourne. "Honest signalling and the billboard effect: how Heliconiid pollinators respond to the trichromatic colour changing Lantana camara L. (Verbenaceae)." Journal of Pollination Ecology 20 (March 21, 2017): 40–50. http://dx.doi.org/10.26786/1920-7603(2017)three.
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Plants communicate with their pollinators through an astonishing range of signals that serve as either honest or deceptive cues which draw in and inform potential visitors of possible rewards. In wild type sweet sage, Lantana camara, floral colour signals were associated with nectar volume and sucrose concentration, and many pollinator taxa quickly learned to associate these varying colour signals with rewards. We tested the hypothesis that if sweet sage is employing a generalist pollinator strategy based on a trichromatic changing floral presentation system of honest rewards for pollinators, then the following predictions will be realized: 1) pre-change yellow flowers will be visited more frequently by pollinators than post change orange, or red flowers; 2) pre-change yellow flowers will produce higher quality and greater quantities of sucrose rewards than post-change orange, or red flowers; 3) inflorescences with higher ratios of rewarding flowers to unrewarding flowers are more attractive at short distances; and 4) inflorescences with a combination of pre-change rewarding and post-change rewarding and unrewarding flowers will act as a multi-coloured advertising billboard and as such be most attractive at long distances. We found corroboration for all of the aforementioned predictions. Thus, sweet sage evolved a generalized pollination visitation system based on honest signalling―of reward quantity and quality tied to colour changing visual signals acting in consort to produce a billboard that was easily perceived and deciphered. These resulted in high visitation rates by many different taxa of pollinators, thus contributing to higher individual plant fitness.
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Diller, Carolina, Miguel Castañeda-Zárate, and Steven D. Johnson. "Generalist birds outperform specialist sunbirds as pollinators of an African Aloe." Biology Letters 15, no. 7 (July 2019): 20190349. http://dx.doi.org/10.1098/rsbl.2019.0349.
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Bird pollination systems are dominated by specialist nectarivores, such as hummingbirds in the Americas and sunbirds in Africa. Opportunistic (generalist) avian nectarivores such as orioles, weavers and bulbuls have also been implicated as plant pollinators, but their effectiveness as agents of pollen transfer is poorly known. Here, we compare the single-visit effectiveness of specialist and opportunistic avian nectarivores as pollinators of Aloe ferox, a plant that relies almost exclusively on birds for seed production. We found that the number of pollen grains on stigmas of flowers receiving single visits by opportunistic avian nectarivores was approximately threefold greater than on those receiving single visits by specialist sunbirds and about twofold greater than on those that received single visits by honeybees. The number of pollen grains on stigmas of flowers visited by sunbirds was similar to that on stigmas of unvisited flowers. These results show that opportunistic birds are highly effective pollinators of A. ferox , supporting the idea that some plants are specialized for pollination by opportunistic birds.
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Gérard, Maxence, Maryse Vanderplanck, Thomas Wood, and Denis Michez. "Global warming and plant–pollinator mismatches." Emerging Topics in Life Sciences 4, no. 1 (April 1, 2020): 77–86. http://dx.doi.org/10.1042/etls20190139.
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The mutualism between plants and their pollinators provides globally important ecosystem services, but it is likely to be disrupted by global warming that can cause mismatches between both halves of this interaction. In this review, we summarise the available evidence on (i) spatial or (ii) phenological shifts of one or both of the actors of this mutualism. While the occurrence of future spatial mismatches is predominantly theoretical and based on predictive models, there is growing empirical evidence of phenological mismatches occurring at the present day. Mismatches may also occur when pollinators and their host plants are still found together. These mismatches can arise due to (iii) morphological modifications and (iv) disruptions to host attraction and foraging behaviours, and it is expected that these mismatches will lead to novel community assemblages. Overall plant–pollinator interactions seem to be resilient biological networks, particularly because generalist species can buffer these changes due to their plastic behaviour. However, we currently lack information on where and why spatial mismatches do occur and how they impact the fitness of plants and pollinators, in order to fully assess if adaptive evolutionary changes can keep pace with global warming predictions.
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Zaninotto, Vincent, Adrien Perrard, Olivier Babiar, Amandine Hansart, Cécile Hignard, and Isabelle Dajoz. "Seasonal Variations of Pollinator Assemblages among Urban and Rural Habitats: A Comparative Approach Using a Standardized Plant Community." Insects 12, no. 3 (February 27, 2021): 199. http://dx.doi.org/10.3390/insects12030199.
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Even though urban green spaces may host a relatively high diversity of wild bees, urban environments impact the pollinator taxonomic and functional diversity in a way that is still misunderstood. Here, we provide an assessment of the taxonomic and functional composition of pollinator assemblages and their response to urbanization in the Paris region (France). We performed a spring-to-fall survey of insect pollinators in green spaces embedded in a dense urban matrix and in rural grasslands, using a plant setup standardized across sites and throughout the seasons. We compared pollinator species composition and the occurrence of bee functional traits over the two habitats. There was no difference in species richness between habitats, though urban assemblages were dominated by very abundant generalist species and displayed a lower evenness. They also included fewer brood parasitic, solitary or ground-nesting bees. Overall, bees tended to be larger in the city than in the semi-natural grasslands, and this trait exhibited seasonal variations. The urban environment filters out some life history traits of insect pollinators and alters their seasonal patterns, likely as a result of the fragmentation and scarcity of feeding and nesting resources. This could have repercussions on pollination networks and the efficiency of the pollination function.
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Hung, Keng-Lou James, Jennifer M. Kingston, Adrienne Lee, David A. Holway, and Joshua R. Kohn. "Non-native honey bees disproportionately dominate the most abundant floral resources in a biodiversity hotspot." Proceedings of the Royal Society B: Biological Sciences 286, no. 1897 (February 20, 2019): 20182901. http://dx.doi.org/10.1098/rspb.2018.2901.
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Most plant–pollinator mutualisms are generalized. As such, they are susceptible to perturbation by abundant, generalist, non-native pollinators such as the western honey bee ( Apis mellifera ), which can reach high abundances and visit flowers of many plant species in their expansive introduced range. Despite the prevalence of non-native honey bees, their effects on pollination mutualisms in natural ecosystems remain incompletely understood. Here, we contrast community-level patterns of floral visitation by honey bees with that of the diverse native pollinator fauna of southern California, USA. We show that the number of honey bees visiting plant species increases much more rapidly with flower abundance than does that of non-honey bee insects, such that the percentage of all visitors represented by honey bees increases with flower abundance. Thus, honey bees could disproportionately impact the most abundantly blooming plant species and the large numbers of both specialized and generalized pollinator species that they sustain. Honey bees may preferentially exploit high-abundance floral resources because of their ability to recruit nest-mates; these foraging patterns may cause native insect species to forage on lower-abundance resources to avoid competition. Our results illustrate the importance of understanding foraging patterns of introduced pollinators in order to reveal their ecological impacts.
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Fontaine, Colin, Carine L. Collin, and Isabelle Dajoz. "Generalist foraging of pollinators: diet expansion at high density." Journal of Ecology 96, no. 5 (June 4, 2008): 1002–10. http://dx.doi.org/10.1111/j.1365-2745.2008.01405.x.
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Machado, Isabel C., Ariadna V. Lopes, and Marlies Sazima. "Contrasting bee pollination in two co-occurring distylic species of Cordia (Cordiaceae, Boraginales) in the Brazilian semi-arid Caatinga: generalist in C. globosa vs. specialist in C. leucocephala." Anais da Academia Brasileira de Ciências 82, no. 4 (December 2010): 881–91. http://dx.doi.org/10.1590/s0001-37652010000400010.
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In this study we compare the reproductive biology of Cordia globosa and C. leucocephala (Cordiaceae, Boraginales; formerly referred to Boraginaceae) to understand the functioning of the floral morphs and the relations with their effective pollinators. The species are synchronopatric, distylic, and self-incompatible. Though they share melittophilous traits, the main visitor and pollinator of C. globosa was the generalist and exotic bee Apis mellifera, while the only one of C. leucocephala was the oligoletic bee Ceblurgus longipalpis. These two latter species are restricted to the Caatinga of NE Brazil, contrasting with the wide distribution of Cordia globosa. While the fruit-set for C. globosa was high, independently if the pollen donor/stigma receptor was a pin (long-styled) or thrum (short-styled) individual, in C. leucocephala the fruit-set was low and occurred only when a thrum individual was the pollen donor. This raises the possibility of this species moving towards dioecy. The high natural fruit-set of C. globosa confirms the generalist bee as its effective pollinator. The low fruit-set after manual crosses in C. leucocephala may be due to low pollen viability. Additionally, the low natural fruit-set (two times lower than after crosses) may be related with the foraging behavior of the specialist pollinator.
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Thompson, Amibeth, Valentin Ștefan, and Tiffany M. Knight. "Oilseed Rape Shares Abundant and Generalized Pollinators with Its Co-Flowering Plant Species." Insects 12, no. 12 (December 8, 2021): 1096. http://dx.doi.org/10.3390/insects12121096.
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Mass-flowering crops, such as Oilseed Rape (OSR), provide resources for pollinators and benefit from pollination services. Studies that observe the community of interactions between plants and pollinators are critical to understanding the resource needs of pollinators. We observed pollinators on OSR and wild plants in adjacent semi-natural areas in Sachsen-Anhalt, Germany to quantify (1) the co-flowering plants that share pollinators with OSR, (2) the identity and functional traits of plants and pollinators in the network module of OSR, and (3) the identity of the plants and pollinators that act as network connectors and hubs. We found that four common plants share a high percentage of their pollinators with OSR. OSR and these plants all attract abundant pollinators in the community, and the patterns of sharing were not more than would be expected by chance sampling. OSR acts as a module hub, and primarily influences the other plants in its module that have similar functional traits. However, the plants that most influence the pollination of OSR have different functional traits and are part of different modules. Our study demonstrates that supporting the pollination of OSR requires the presence of semi-natural areas with plants that can support a high abundances of generalist pollinators.
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Keasar, Tamar. "Large Carpenter Bees as Agricultural Pollinators." Psyche: A Journal of Entomology 2010 (2010): 1–7. http://dx.doi.org/10.1155/2010/927463.
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Large carpenter bees (genusXylocopa) are wood-nesting generalist pollinators of broad geographical distribution that exhibit varying levels of sociality. Their foraging is characterized by a wide range of food plants, long season of activity, tolerance of high temperatures, and activity under low illumination levels. These traits make them attractive candidates for agricultural pollination in hot climates, particularly in greenhouses, and of night-blooming crops. Carpenter bees have demonstrated efficient pollination service in passionflower, blueberries, greenhouse tomatoes and greenhouse melons. Current challenges to the commercialization of these attempts lie in the difficulties of mass-rearingXylocopa, and in the high levels of nectar robbing exhibited by the bees.
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Schwarz, Benjamin, Carsten F. Dormann, Diego P. Vázquez, and Jochen Fründ. "Within-day dynamics of plant–pollinator networks are dominated by early flower closure: an experimental test of network plasticity." Oecologia 196, no. 3 (June 3, 2021): 781–94. http://dx.doi.org/10.1007/s00442-021-04952-5.
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AbstractTemporal variability of plant–pollinator interactions is important for fully understanding the structure, function, and stability of plant–pollinator networks, but most network studies so far have ignored within-day dynamics. Strong diel dynamics (e.g., a regular daily cycle) were found for networks with Cichorieae, which typically close their flowers around noon. Here, we experimentally prevented early flower closure to test whether these dynamics are driven by the temporally limited availability of Cichorieae, or by timing of pollinator activity. We further tested if the dynamics involving Cichorieae and their pollinators also affect the dynamics on other plants in the network. Finally, we explored the structure of such manipulated networks (with Cichorieae available in the morning and afternoon) compared to unmanipulated controls (Cichorieae available only in the morning). We found that flower closure of Cichorieae is indeed an important driver of diel network dynamics, while other drivers of pollinator timing appeared less important. If Cichorieae flowers were available in the afternoon, they were visited by generalist and specialist pollinators, which overall decreased link turnover between morning and afternoon. Effects of afternoon availability of Cichorieae on other plants in the network were inconclusive: pollinator switching to and from Cichorieae tended to increase. On the level of the aggregated (full-day) network, the treatment resulted in increased dominance of Cichorieae, reducing modularity and increasing plant generality. These results highlight that network dynamics can be predicted by knowledge of diel or seasonal phenology, and that fixed species timing assumptions will misrepresent the expected dynamics.
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Montesinos, Daniel, Sílvia Castro, and Susana Rodríguez-Echeverría. "Two invasive acacia species secure generalist pollinators in invaded communities." Acta Oecologica 74 (July 2016): 46–55. http://dx.doi.org/10.1016/j.actao.2016.06.002.
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Parys, Katherine A., Isaac L. Esquivel, Karen W. Wright, Terry Griswold, and Michael J. Brewer. "Native Pollinators (Hymenoptera: Anthophila) in Cotton Grown in the Gulf South, United States." Agronomy 10, no. 5 (May 14, 2020): 698. http://dx.doi.org/10.3390/agronomy10050698.
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Native bees (Hymenoptera: Anthophila) were sampled using bee bowls in two states to determine biodiversity in commercial cotton fields of the southern United States. In both states, native bee communities found in cotton fields were dominated by generalist pollinators in the genera Agapostemon, Augochloropsis, Halictus, and Lasioglossum (Hymenoptera: Halictidae), and Melissodes (Hymenoptera: Apidae). Melissodes tepaneca (Cresson) was the most abundant species found in cotton fields in both states. Some species collected are known specialists on other plant taxa, suggesting they may be tourist species. Here we provide a baseline species list of native bees found in cotton. Ordination indicated separation between the communities found in the two states when pooled by genus, but these differences were not significant. While cotton is grown in highly managed and disturbed landscapes, our data suggest that a community of common generalist native pollinators persists. Many of these species are also found in other cropping systems across North America.
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Dáttilo, Wesley, Carlos Pinilla Cruz, Pedro Luna, Brenda Ratoni, Ismael A. Hinojosa-Díaz, Frederico S. Neves, Maurice Leponce, Fabricio Villalobos, and Roger Guevara. "The Impact of the Honeybee Apis mellifera on the Organization of Pollination Networks Is Positively Related with Its Interactive Role throughout Its Geographic Range." Diversity 14, no. 11 (October 27, 2022): 917. http://dx.doi.org/10.3390/d14110917.
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Studies at local spatial scales have shown that the generalist honeybee Apis mellifera L. can strongly affect the structural organization and properties of pollination networks. However, there is still little knowledge on how the connectivity of the honeybee within networks (i.e., interactive role) could affect pollination networks at a global scale. To fill this gap, we evaluated how the interactive role of A. mellifera could affect niche overlap, specialization, and robustness of pollination networks. We used 109 weighted pollination networks spread across about 94 degrees of latitude and 227 degrees of longitude. We developed a new standardized framework based on species removal to assess the impact of the honeybee on plant-pollinator networks. We found that when the honeybee was removed from the networks, plant species had less niche overlap (i.e., shared fewer interactions via their pollinators) and the networks became more specialized and more robust to species extinctions. Our findings indicate that A. mellifera’s effects on pollination networks vary geographically and could influence several ecological and evolutionary factors acting at local scales, including pollination services. We hope this contribution will stimulate new macroecological studies involving abundant and generalist species and their functional roles within ecological communities.
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Gómez, José M., M. Abdelaziz, J. P. M. Camacho, A. J. Muñoz-Pajares, and F. Perfectti. "Local adaptation and maladaptation to pollinators in a generalist geographic mosaic." Ecology Letters 12, no. 7 (July 2009): 672–82. http://dx.doi.org/10.1111/j.1461-0248.2009.01324.x.
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Erickson, E., S. Adam, L. Russo, V. Wojcik, H. M. Patch, and C. M. Grozinger. "More Than Meets the Eye? The Role of Annual Ornamental Flowers in Supporting Pollinators." Environmental Entomology 49, no. 1 (November 22, 2019): 178–88. http://dx.doi.org/10.1093/ee/nvz133.
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Abstract Ornamental flowers are commonly planted in urban and suburban areas to provide foraging resources for pollinator populations. However, their role in supporting broad pollinator biodiversity is not well established as previous studies have been conducted in urban landscapes with pollinator communities that are distinct from those in natural systems. We observed pollinator visitation patterns to five ornamental annual plant genera and their cultivars over multiple years at two semi-natural sites in Pennsylvania to understand their potential for supporting diverse pollinator communities. There was significant variation in visitor abundance and diversity by season and year for many annual ornamental cultivars. Within some genera, cultivars had similar visitor abundance, diversity, and main visitor taxa, while cultivars in other genera varied greatly in these measures. We observed only polylectic (pollen generalist) bee species visiting annual ornamentals, despite the presence of oligolectic (pollen specialist) bee species in the background population. We conclude that the attractiveness of annual ornamental plants likely depends on both cultivar characteristics and environmental context. While their role in supporting complex pollinator populations is limited both based on the number of and dietary breadth of the species they support, ornamental plants may nonetheless provide long-lasting supplemental foraging resources for the generalist pollinator communities characteristic of urban and suburban environments.
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Catling, Paul M. "Osmia species (Megachilidae) pollinate Cypripedium parviflorum (Orchidaceae) and Packera paupercula (Asteraceae): a localized case of Batesian mimicry?" Canadian Field-Naturalist 129, no. 1 (June 1, 2015): 38. http://dx.doi.org/10.22621/cfn.v129i1.1665.
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The pollinator-non-rewarding Large Yellow Lady's-slipper (Cypripedium parviflorum var. pubescens [Willdenow] Knight) and the rewarding Balsam Ragwort (Packera paupercula [Michaux] Á. Löve & D. Löve) exist together in some eastern Ontario alvars where they share a group of medium-sized, dark blue metallic pollinators in the bee genus Osmia (Mason Bees, Megachilidae). I provide evidence of floral mimicry of the ragwort by the orchid based on several observations: (1) Osmia visiting P. paupercula also visit C. parviflorum var. pubescens; (2) Osmia are more frequent visitors to P. paupercula than to other co-blooming plants; (3) Osmia are the primary pollinators of C. parviflorum var. pubescens; (4) the behaviour of Osmia on the flower of C. parviflorum var. pubescens involving landing on the staminode suggests mimicry; and (5) the largest populations of C. parviflorum var. pubescens in Ontario are in alvar landscapes where P. paupercula is abundant. Pollination in Large Yellow Lady's-slipper may vary geographically from non-model to species-specific Batesian mimicry, which is rare in orchids. This latter pollination mechanism may have evolved in ice-front environments during the Pleistocene, but then became isolated to unusual partial analogues of ice-front habitat during the Holocene with pollination in most of the current range appearing to be a generalist strategy.
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Ryniewicz, Justyna, Mateusz Skłodowski, Magdalena Chmur, Andrzej Bajguz, Katarzyna Roguz, Agata Roguz, and Marcin Zych. "Intraspecific Variation in Nectar Chemistry and Its Implications for Insect Visitors: The Case of the Medicinal Plant, Polemonium Caeruleum L." Plants 9, no. 10 (October 1, 2020): 1297. http://dx.doi.org/10.3390/plants9101297.
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Floral nectar, being a primary reward for insect visitors, is a key factor in shaping plant–pollinator interactions. However, little is known about the variability in nectar traits, which could potentially affect pollinators and the reproduction of the species. We investigated intraspecific variation in nectar traits in 14 populations of a Red-listed plant, Polemonium caeruleum. Populations varied in terms of the proportion of self-compatible and self-incompatible individuals, and insect communities visiting flowers. Using HPLC, we determined the nectar sugar and amino acid (AA) composition and concentration. We also recorded some basic habitat parameters, which could influence nectar chemistry. In seven selected populations, we investigated the taxonomic composition of the insects visiting flowers. Our observations revealed significant intraspecific variability in nectar chemistry in P. caeruleum. Nectar production was male-biased, with male-phase flowers secreting sucrose- and AA-rich nectar. An analysis revealed that variability in P. caeruleum nectar may be slightly shaped by environmental factors. The studied nectar characters, especially sugars, had little effect on insects visiting flowers. We argue that variation in nectar traits in this generalist plant is a matter of random genetic drift or “adaptive wandering” rather than directional specialization and adaptation in the most effective and abundant group of pollinators.
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Kőrösi, Ádám, Viktor Markó, Anikó Kovács-Hostyánszki, László Somay, Ákos Varga, Zoltán Elek, Virginie Boreux, Alexandra-Maria Klein, Rita Földesi, and András Báldi. "Climate-induced phenological shift of apple trees has diverse effects on pollinators, herbivores and natural enemies." PeerJ 6 (July 26, 2018): e5269. http://dx.doi.org/10.7717/peerj.5269.
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Climate change is altering the phenology of trophically linked organisms, leading to increased asynchrony between species with unknown consequences for ecosystem services. Although phenological mismatches are reported from several ecosystems, experimental evidence for altering multiple ecosystem services is hardly available. We examined how the phenological shift of apple trees affected the abundance and diversity of pollinators, generalist and specialist herbivores and predatory arthropods. We stored potted apple trees in the greenhouse or cold store in early spring before transferring them into orchards to cause mismatches and sampled arthropods on the trees repeatedly. Assemblages of pollinators on the manipulated and control trees differed markedly, but their overall abundance was similar indicating a potential insurance effect of wild bee diversity to ensure fruit set in flower-pollinator mismatch conditions. Specialized herbivores were almost absent from manipulated trees, while less-specialized ones showed diverse responses, confirming the expectation that more specialized interactions are more vulnerable to phenological mismatch. Natural enemies also responded to shifted apple tree phenology and the abundance of their prey. While arthropod abundances either declined or increased, species diversity tended to be lower on apple trees with shifted phenology. Our study indicates novel results on the role of biodiversity and specialization in plant-insect mismatch situations.
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Dorado, Jimena, and Diego P. Vázquez. "Flower diversity and bee reproduction in an arid ecosystem." PeerJ 4 (July 26, 2016): e2250. http://dx.doi.org/10.7717/peerj.2250.
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Background:Diverse flower communities are more stable in floral resource production along the flowering season, but the question about how the diversity and stability of resources affect pollinator reproduction remains open. High plant diversity could favor short foraging trips, which in turn would enhance bee fitness. In addition to plant diversity, greater temporal stability of floral resources in diverse communities could favor pollinator fitness because such communities are likely to occupy the phenological space more broadly, increasing floral availability for pollinators throughout the season. In addition, this potential effect of flower diversity on bee reproduction could be stronger for generalist pollinators because they can use a broader floral spectrum. Based on above arguments we predicted that pollinator reproduction would be positively correlated to flower diversity, and to temporal stability in flower production, and that this relationship would be stronger for the most generalized pollinator species.Materials and Methods:Using structural equation models, we evaluated the effect of these variables and other ecological factors on three estimates of bee reproduction (average number of brood cells per nest per site, total number of brood cells per site, and total number of nests per site), and whether such effects were modulated by bee generalization on floral resources.Results:Contrary to our expectations, flower diversity had no effect on bee reproduction, stability in flower production had a weakly negative effect on one of the bee reproductive variables, and the strength of the fitness-diversity relationship was unrelated to bee generalization. In contrast, elevation had a negative effect on bee reproduction, despite the narrow elevation range encompassed by our sites.Discussion:Flower diversity did not affect the reproduction of the solitary bees studied here. This result could stem from the context dependence of the diversity-stability relationship, given that elevation had a positive effect on flower diversity but a negative effect on bee reproduction. Although high temporal stability in flower production is expected to enhance pollinator reproduction, in our study it had a weakly negative—instead of positive—effect on the average number of brood cells per nest. Other environmental factors that vary with elevation could influence bee reproduction. Our study focused on a small group of closely-related bee species, which cautions against generalization of our findings to other groups of pollinators. More studies are clearly needed to assess the extent to which pollinator demography is influenced by the diversity of floral resources.
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Brzosko, Emilia, Andrzej Bajguz, Justyna Burzyńska, and Magdalena Chmur. "Nectar Chemistry or Flower Morphology—What Is More Important for the Reproductive Success of Generalist Orchid Epipactis palustris in Natural and Anthropogenic Populations?" International Journal of Molecular Sciences 22, no. 22 (November 10, 2021): 12164. http://dx.doi.org/10.3390/ijms222212164.
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The aim of this study was to determine the level of reproductive success (RS) in natural and anthropogenic populations of generalist orchid Epipactis palustris and its dependence on flower structure and nectar composition, i.e., amino acids and sugars. We found that both pollinaria removal and female reproductive success were high and similar in all populations, despite differences in flower traits and nectar chemistry. Flower structures were weakly correlated with parameters of RS. Nectar traits were more important in shaping RS; although, we noted differentiated selection on nectar components in distinct populations. Individuals in natural populations produced nectar with a larger amount of sugars and amino acids. The sucrose to (fructose and glucose) ratio in natural populations was close to 1, while in anthropogenic ones, a clear domination of fructose and glucose was noted. Our results indicate that the flower traits and nectar composition of E. palustris reflect its generalist character and meet the requirements of a wide range of pollinators, differing according to body sizes, mouth apparatus, and dietary needs. Simultaneously, differentiation of nectar chemistry suggests a variation of pollinator assemblages in particular populations or domination of their some groups. To our knowledge, a comparison of nectar chemistry between natural and anthropogenic populations of orchids is reported for the first time in this paper.
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Barrett, Matthew R., Camila C. Filgueiras, and Denis S. Willett. "Using Cucumis sativus, Acalymma vittatum, Celatoria setosa, and generalist pollinators as a case study for plant–insect interactions." Arthropod-Plant Interactions 15, no. 5 (July 13, 2021): 637–44. http://dx.doi.org/10.1007/s11829-021-09852-2.
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AbstractShowcasing how semiochemicals are both multifunctional and can influence a community of organisms is a constant frontier shared by chemical ecologists and applied entomologists alike. As researchers in these fields continue to share broad and overlapping interests, converging on one system could allow for a better understanding of community interactions and the chemical substances that mediate them. Cucurbit systems are strategically positioned to study these types of interactions because they combine the elements of plant–herbivore, plant–predator, and plant pollinator into one model and are systems where researchers can pursue both basic and applied questions. In this review, we propose Cucumis sativus [cucumber], Acalymma vittatum [striped cucumber beetle], Celatoria setosa [a natural enemy], and generalist pollinators as a system for continued investigation into semiochemicals, their multifunctional roles, and their influence on both target and nontarget organisms. We believe this system is ripe for further exploration at the frontiers in chemical ecology and applied entomology.
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DEVAUX, C., and R. LANDE. "Displacement of flowering phenologies among plant species by competition for generalist pollinators." Journal of Evolutionary Biology 22, no. 7 (July 2009): 1460–70. http://dx.doi.org/10.1111/j.1420-9101.2009.01762.x.
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Holzschuh, Andrea, Carsten F. Dormann, Teja Tscharntke, and Ingolf Steffan-Dewenter. "Expansion of mass-flowering crops leads to transient pollinator dilution and reduced wild plant pollination." Proceedings of the Royal Society B: Biological Sciences 278, no. 1723 (April 6, 2011): 3444–51. http://dx.doi.org/10.1098/rspb.2011.0268.
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Agricultural land use results in direct biodiversity decline through loss of natural habitat, but may also cause indirect cross-habitat effects on conservation areas. We conducted three landscape-scale field studies on 67 sites to test the hypothesis that mass flowering of oilseed rape ( Brassica napus ) results in a transient dilution of bees in crop fields, and in increased competition between crop plants and grassland plants for pollinators. Abundances of bumble-bees, which are the main pollinators of the grassland plant Primula veris , but also pollinate oilseed rape (OSR), decreased with increasing amount of OSR. This landscape-scale dilution affected bumble-bee abundances strongly in OSR fields and marginally in grasslands, where bumble-bee abundances were generally low at the time of Primula flowering. Seed set of Primula veris , which flowers during OSR bloom, was reduced by 20 per cent when the amount of OSR within 1 km radius increased from 0 to 15 per cent. Hence, the current expansion of bee-attractive biofuel crops results in transient dilution of crop pollinators, which means an increased competition for pollinators between crops and wild plants. In conclusion, mass-flowering crops potentially threaten fitness of concurrently flowering wild plants in conservation areas, despite the fact that, in the long run, mass-flowering crops can enhance abundances of generalist pollinators and their pollination service.
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Amy, Clara, Grégoire Noël, Séverin Hatt, Roel Uyttenbroeck, Frank Van de Meutter, David Genoud, and Frédéric Francis. "Flower Strips in Wheat Intercropping System: Effect on Pollinator Abundance and Diversity in Belgium." Insects 9, no. 3 (September 4, 2018): 114. http://dx.doi.org/10.3390/insects9030114.
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The decline of pollinators in agricultural areas has been observed for some decades, this being partly due to landscape simplification in intensive agrosystems. Diversifying agricultural landscapes by sowing flower strips within fields could reduce these adverse effects on biodiversity. In this context, the study presented here aimed at assessing and comparing the abundance and diversity of bees (Hymenoptera: Anthophila) and hoverflies (Diptera: Syrphidae) found and visiting flowers in three types of flower strips in Belgium: (i) a mixture of 11 wild flowers, (ii) a monofloral strip of Dimorphoteca pluvialis (Asteraceae) and (iii) a monofloral strip of Camelina sativa (Brassicaceae), where the last two are considered to be intercrops since they are valuable on the market, all sown within a field of winter wheat (Triticum aestivum L.). Pollinators were captured with pan traps and by netting in standardised transects from May to July 2017. One-thousand one-hundred and eighty-four individuals belonging to 43 bee species and 18 hoverfly species were collected. Significant differences in hoverfly diversity were found between the different flower strips. The multifloral treatment supported a greater diversity of syrphid species. Various pollinator species visited the different flowers composing the mixture and also D. pluvialis. The pollinator community proved to be predominantly generalist, with the exception of an oligolectic species in Belgium, Andrena nitidiuscula. Moreover, the three tested flower strips were effective in attracting hoverflies, among them natural enemies of insect pests. This study opens new perspectives in the design of intercropping systems with flower strips towards the design of sustainable agro-ecosystems. Improving economic profitability of sowing flower strips could encourage farmers to diversify their agricultural systems and foster conservation biology strategies.
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Rech, André Rodrigo, Fatima Cristina de Lazari Manente-Balestieri, and Maria Lúcia Absy. "Reproductive biology of Davilla kunthii A. St-Hil. (Dilleniaceae) in Central Amazonia." Acta Botanica Brasilica 25, no. 2 (June 2011): 487–96. http://dx.doi.org/10.1590/s0102-33062011000200024.
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This survey aimed at describing the interactions of floral visitors and Davilla kunthii A. St.-Hil. as well as characteristics of its reproductive biology in Itacoatiara, state of Amazonas, Brazil. Tests of the breeding system were performed. The guild of visitors was described according to richness, abundance, relative frequency and constancy. The breeding system tests indicated that D. kunthii is self-compatible. The pollination system was characterized as generalist, with 39 visitor species, from three different orders. Bees were the main group of pollinators, thus some behavioural aspects were described. Th e period of highest foraging activity was between 7 and 10 am. Some species presented agonistic and monopolistic behaviour. Given the behaviour and destructive potential, the Curculionidae seem to have a greater impact as seed predators than pollinators.
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Gómez, José M., Francisco Perfectti, and Juan Lorite. "The role of pollinators in floral diversification in a clade of generalist flowers." Evolution 69, no. 4 (April 2015): 863–78. http://dx.doi.org/10.1111/evo.12632.
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Dilley, James D., Paul Wilson, and Michael R. Mesler. "The radiation of Calochortus : generalist flowers moving through a mosaic of potential pollinators." Oikos 89, no. 2 (May 2000): 209–22. http://dx.doi.org/10.1034/j.1600-0706.2000.890201.x.
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Sprague, Rowan, Stéphane Boyer, Georgia M. Stevenson, and Steve D. Wratten. "Assessing pollinators’ use of floral resource subsidies in agri-environment schemes: An illustration usingPhacelia tanacetifoliaand honeybees." PeerJ 4 (November 15, 2016): e2677. http://dx.doi.org/10.7717/peerj.2677.
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BackgroundHoneybees (Apis melliferaL.) are frequently used in agriculture for pollination services because of their abundance, generalist floral preferences, ease of management and hive transport. However, their populations are declining in many countries. Agri-Environment Schemes (AES) are being implemented in agricultural systems to combat the decline in populations of pollinators and other insects. Despite AES being increasingly embedded in policy and budgets, scientific assessments of many of these schemes still are lacking, and only a few studies have examined the extent to which insect pollinators use the floral enhancements that are part of AES and on which floral components they feed (i.e., pollen and/or nectar).MethodsIn the present work, we used a combination of observations on honeybee foraging for nectar/pollen from the Californian annual plantPhacelia tanacetifoliain the field, collection of pollen pellets from hives, and pollen identification, to assess the value of adding phacelia to an agro-ecosystem to benefit honeybees.ResultsIt was found that phacelia pollen was almost never taken by honeybees. The work here demonstrates that honeybees may not use the floral enhancements added to a landscape as expected and points to the need for more careful assessments of what resources are used by honeybees in AES and understanding the role, if any, which AES play in enhancing pollinator fitness.DiscussionWe recommend using the methodology in this paper to explore the efficacy of AES before particular flowering species are adopted more widely to give a more complete illustration of the actual efficacy of AES.
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Ahrenfeldt, Erica Juel, Johannes Kollmann, Henning Bang Madsen, Hans Skov-Petersen, and Lene Sigsgaard. "Generalist solitary ground-nesting bees dominate diversity survey in intensively managed agricultural land." Journal of Melittology, no. 82 (January 23, 2019): 1–12. http://dx.doi.org/10.17161/jom.v0i82.7057.
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In Western Europe agricultural management was intensified in the period 1950–2010 with negative consequences for ecosystem services, such as pollination, especially in countries with a large proportion of agriculture. Farmland represents 66% of the Danish landscape, but little is known about wild bees despite that 75% of the country’s wild and cultivated plant species depend on insect pollination. Strawberry (Fragaria × ananassa) gains considerable benefits from insect pollination and abundance, species richness and functional diversity, are all important elements. We surveyed the diversity of wild bees during strawberry flowering by sampling bees with pan-traps along permanent margins bordering strawberry fields on six organic and six conventional farms in eastern Denmark and compared the results of the survey with that of sampling site farming practice and field margin forage availability. The majority of bees sampled were polylectic solitary ground-nesting bees known to forage on species of the rose family. This indicates that these bee species are potential pollinators of strawberries, and the low number of specialized bees suggests that the bee community was affected by the simplified landscapes. Temporal trends in abundance, species richness, and body size of the bees, suggest that the functional diversity of pollinator assemblages available differed for early- and late-flowering strawberries. Fewer plants species and a lower plant cover were found in the margins of sprayed fields. Abundance and diversity of the wild bees were neither correlated with the use of herbicides and insecticides, nor with plant species richness or flowering plant cover.
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Larson, B. M. H., P. G. Kevan, and D. W. Inouye. "Flies and flowers: taxonomic diversity of anthophiles and pollinators." Canadian Entomologist 133, no. 4 (August 2001): 439–65. http://dx.doi.org/10.4039/ent133439-4.
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AbstractThe Diptera are the second most important order among flower-visiting (anthophilous) and flower-pollinating insects worldwide. Their taxonomic diversity ranges from Nematocera to Brachycera, including most families within the suborders. Especially important are Syrphidae, Bombyliidae, and Muscoidea. Other families, especially of small flies, are less appreciated and often overlooked for their associations with flowers. We have compiled records of their flower visitations to show that they may be more prevalent than usually thought. Our knowledge of anthophilous Diptera needs to be enhanced by future research concerning (i) the significance of nocturnal Nematocera and acalypterate muscoids as pollinators, (ii) the extent to which the relatively ineffective pollen-carrying ability of some taxa can be compensated by the abundance of individuals, and (iii) the role of Diptera as pollinators of the first flowering plants (Angiospermae) by using phylogenetic and palaeontological evidence. Specializations in floral relationships involve the morphology of Diptera, especially of their mouthparts, nutritional requirements, and behaviour, as well as concomitant floral attributes. The South African flora has the most highly specialized relations with dipterous pollinators, but in arctic and alpine generalist fly–flower relations are important in pollination and fly nutrition.
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Sharma, Manju V., and Kundaranahalli R. Shivanna. "Pollinators, pollination efficiency and fruiting success in a wild nutmeg, Myristica dactyloides." Journal of Tropical Ecology 27, no. 4 (May 31, 2011): 405–12. http://dx.doi.org/10.1017/s0266467411000174.
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Abstract:We investigated the pollinator assemblage in Myristica dactyloides, a dioecious tree species occupying the intermediate canopy stratum of the mid- and high-elevation wet evergreen forests and endemic to Sri Lanka and the Western Ghats of India. We surveyed two populations and, in one of them, marked four male and three female trees for observations on floral display and insect foraging, and two female trees for experimental pollination. Yellow sticky traps were used to sample insects in the canopy during the flowering season of December 2007 in addition to direct observations of insect activity in 2006. Myristicaceae members from other tropical areas have been reported to be specialized to beetle pollination, but our observations provide evidence of a generalist pollination system in M. dactyloides, composed of small, diverse insects: thysanopterans (thrips), coleopterans (beetles), halictid bees and dipterans (syrphid and phorid flies). Quantifying floral display, we found that female inflorescences were smaller, offered no reward and attracted significantly fewer pollinators in comparison to male inflorescences. Fruit set was low and could be attributed to a 29% flower abscission and abortion of young fruits, but a reasonably high natural pollination efficiency combined with pollination experiments established that there was no pollination limitation in the study population.
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Quakenbush, Peter J. "Pollination, Mating System, Phenology and Characterisation of Medinilla multiflora Merr. (Melastomataceae) on Mt Makiling, Philippines." Sibbaldia: the International Journal of Botanic Garden Horticulture, no. 16 (July 26, 2018): 121–39. http://dx.doi.org/10.24823/sibbaldia.2018.251.
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An investigation into the reproductive biology of Medinilla multiflora Merr. (Melastomataceae) from Mt Makiling, Luzon, is presented. This includes a morphological and distributional examination of the population on the mountain, the documentation of reproductive phenological patterns, a study of the mating system and observations of biotic interactions. Measurements were made of trait variability, reproductive phenology was characterised from field and herbarium observations, stigmatic receptivity was tested by counting pollen germination, insect exclusion and hand-pollination experiments helped determine the mating system and field observations recorded the identity and behaviour of floral visitors. Significant reproductive morphological differences were found between described populations. This identified a need for the recognition of this diversity and further delimitation of the Medinilla multiflora species complex. Although Medinilla multiflora produced flowers and fruit year-round, the population also exhibited cycles of increased reproduction most likely initiated by seasonal low temperatures. Medinilla multiflora was found to require pollination but not cross-pollination. Two major peaks in stigmatic receptivity occurred throughout the day and the majority of pollen was found to be viable. Generalist bees proved to be the primary pollinators of the study population and were most active in the morning depending on weather conditions. Generalist pollinators and self-compatibility are advantageous traits for establishment and persistence in isolated mountain habitats; however, losses of this habitat due to climate change could have profound consequences for the future success of Medinilla multiflora.
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MATSUYAMA, SHUHEI, NAOYA OSAWA, and MICHINORI SAKIMOTO. "Generalist pollinators in the dioecious shrubRhus trichocarpaMiq. (Anacardiaceae) and their role in reproductive success." Plant Species Biology 24, no. 3 (December 2009): 215–24. http://dx.doi.org/10.1111/j.1442-1984.2009.00258.x.
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