Academic literature on the topic 'Plant-pollinator interactions'

Abstract Aims Plant–pollinator interaction networks are dynamic entities, and seasonal variation in plant phenology can reshape their structure on both short and long timescales. However, such seasonal dynamics are rarely considered, especially for oceanic island pollination networks. Here, we assess changes in the temporal dynamics of plant–pollinator interactions in response to seasonal variation in floral resource richness in oceanic island communities. Methods We evaluated seasonal variations of pollination networks in the Yongxing Island community. Four temporal qualitative pollination networks were analyzed using plant–pollinator interaction data of the four seasons. We collected data on plant–pollinator interactions during two consecutive months in each of the four seasons. Four network-level indices were calculated to characterize the overall structure of the networks. Statistical analyses of community dissimilarity were used to compare this community across four seasons to explore the underlying factors driving these patterns. We also evaluated the temporal variation in two species-level indices of plant and pollinator functional groups. Important Findings Both network-level specialization and modularity showed a significantly opposite trend compared with plant species richness across four seasons. Increased numbers of plant species might promote greater competition among pollinators, leading to increased niche overlap and causing decreased specialization and modularity and vice versa. Further analyses suggested that the season-to-season turnover of interactions was dominated by interaction rewiring. Thus, the seasonal changes in niche overlap among pollinators lead to interaction rewiring, which drives interaction turnover in this community. Hawkmoths had higher values of specialization and Apidae had higher values of species strength compared with other pollinator functional groups. These findings should be considered when exploring plant–pollinator interactions in ecosystems of isolated oceanic islands and in other ecosystems.

Coffee (genus Coffea L.) is one of the most critical global agricultural crops. Many studies have focused on coffee plants and their associated insects. This review will summarize work specifically relating to coffee plant – pollinator interactions. We review the current status of coffee as a worldwide commodity, botanical aspects of coffee, and insects associated with coffee pollination, and we assess the current understanding of the role of different pollinator taxa in increasing fruit set and yield.

The Brazilian Plant-Pollinator Interactions Network*1 (REBIPP) aims to develop scientific and teaching activities in plant-pollinator interaction. The main goals of the network are to: generate a diagnosis of plant-pollinator interactions in Brazil; integrate knowledge in pollination of natural, agricultural, urban and restored areas; identify knowledge gaps; support public policy guidelines aimed at the conservation of biodiversity and ecosystem services for pollination and food production; and encourage collaborative studies among REBIPP participants. To achieve these goals the group has resumed and built on previous works in data standard definition done under the auspices of the IABIN-PTN (Etienne Américo et al. 2007) and FAO (Saraiva et al. 2010) projects (Saraiva et al. 2017). The ultimate goal is to standardize the ways data on plant-pollinator interactions are digitized, to facilitate data sharing and aggregation. A database will be built with standardized data from Brazilian researchers members of the network to be used by the national community, and to allow sharing data with data aggregators. To achieve those goals three task groups of specialists with similar interests and background (e.g botanists, zoologists, pollination biologists) have been created. Each group is working on the definition of the terms to describe plants, pollinators and their interactions. The glossary created explains their meaning, trying to map the suggested terms into Darwin Core (DwC) terms, and following the TDWG Standards Documentation Standard*2 in definition. Reaching a consensus on terms and their meaning among members of each group is challenging, since researchers have different views and concerns about which data are important to be included into a standard. That reflects the variety of research questions that underlie different projects and the data they collect. Thus, we ended up having a long list of terms, many of them useful only in very specialized research protocols and experiments, sometimes rarely collected or measured. Nevertheless we opted to maintain a very comprehensive set of terms, so that a large number of researchers feel that the standard meets their needs and that the databases based on it are a suitable place to store their data, thus encouraging the adoption of the data standard. An update of the work will soon be available at REBIPP website and will be open for comments and contributions. This proposal of a data standard is also being discussed within the TDWG Biological Interaction Data Interest Group*3 in order to propose an international standard for species interaction data. The importance of interaction data for guiding conservation practices and ecosystem services provision management has led to the proposal of defining Essential Biodiversity Variables (EBVs) related to biological interactions. Essential Biodiversity Variables (Pereira et al. 2013) were developed to identify key measurements that are required to monitoring biodiversity change. EBVs act as intermediate abstract layer between primary observations (raw data) and indicators (Niemeijer 2002). Five EBV classes have been defined in an initial stage: genetic composition, species populations, species traits, community composition, ecosystem function and ecosystem structure. Each EBV class defines a list of candidate EBVs for biodiversity change monitoring (Fig. 1). Consequently, digitalization of such data and making them available online are essential. Differences in sampling protocols may affect data scalability across space and time, hence imposing barriers to the full use of primary data and EBVs calculation (Henry et al. 2008). Thus, common protocols and methods should be adopted as the most straightforward approach to promote integration of collected data and to allow calculation of EBVs (Jürgens et al. 2011). Recently a Workshop was held by GLOBIS B*4 (GLOBal Infrastructures for Supporting Biodiversity research) to discuss Species Interactions EBVs (February, 26-28, Bari, Italy). Plant-pollinator interactions deserved a lot of attention and REBIPP's work was presented there. As an outcome we expect to define specific EBVs for interactions, and use plant-pollinators as an example, considering pairwise interactions as well as interaction network related variables. The terms in the plant-pollinator data standard under discussion at REBIPP will provide information not only on EBV related with interactions, but also on other four EBV classes: species populations, species traits, community composition, ecosystem function and ecosystem structure. As we said, some EBVs for specific ecosystem functions (e.g. pollination) lay beyond interactions network structures. The EBV 'Species interactions' (EBV class 'Community composition') should incorporate other aspects such as frequency (Vázquez et al. 2005), duration and empirical estimates of interaction strengths (Berlow et al. 2004). Overall, we think the proposed plant-pollinator interaction data standard which is currently being developed by REBIPP will contribute to data aggregation, filling many data gaps and can also provide indicators for long-term monitoring, being an essential source of data for EBVs.

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.

Plants are the foundation of the food web and therefore interact directly and indirectly with myriad organisms at higher trophic levels. They directly provide nourishment to mutualistic and antagonistic primary consumers (e.g., pollinators and herbivores), which in turn are consumed by predators. These interactions produce cascading indirect effects on plants (either trait-mediated or density-mediated). We review how predators affect plant-pollinator interactions and thus how predators indirectly affect plant reproduction, fitness, mating systems, and trait evolution. Predators can influence pollinator abundance and foraging behavior. In many cases, predators cause pollinators to visit plants less frequently and for shorter durations. This decline in visitation can lead to pollen limitation and decreased seed set. However, alternative outcomes can result due to differences in predator, pollinator, and plant functional traits as well as due to altered interaction networks with plant enemies. Furthermore, predators may indirectly affect the evolution of plant traits and mating systems.

Previous work has demonstrated that coflowering plant species (those that flower simultaneously in the same place) can potentially compete for pollination services. Competition for pollination among plant species can negatively impact their reproductive success. To minimise competition, plants can partition the activity of shared pollinators through releasing their floral resources at different times. Resource partitioning has been studied in several individual plant species, and some guilds of plants (e.g. African acacias), but little is known about temporal changes in resources at a community level. This thesis examines the spatiotemporal changes of floral resources at a community level and its implications for pollinator activity patterns. The temporal patterns of nectar and pollen provision of 70 plant species in two different plots were investigated at Mpala, in north central Kenya between 2004 and 2006. The communities studied showed that seasonal and daily microclimatic fluctuations significantly affect flowering patterns, times of flower opening, dehiscence and nectar production; and consequently the overall amount of pollen mass and nectar volume available at different times. I explored the effects of daily temporal changes in floral resource availability on pollinator activity patterns both in a guild of Malvaceae plant species, and at the community level through pollination webs. Detailed observations of daily patterns of resource provision and floral visitation in six Malvaceae plant species showed that plants can effectively avoid competition through attracting different pollinators, and via resource partition. Examination of daily changes in resource availability and the links portrayed in plant-visitor webs revealed that visitors move from one plant species to another, actively tracking changes in floral resource provision. These results suggest that in combination with physiological limitations imposed to the pollinators by temperature, bottom-up influences are a main force shaping daily pollinator activity patterns at a community level. Competition for pollination can only occur if plant species flower simultaneously and share pollinators within the same geographic area. Competition for pollination has been investigated in at least two African communities, but none of these studies have assessed the geographic spatial scale over which competition among coflowering species might happen. With the aim of measuring the geographic distance that pollinators visiting African acacias fly whilst foraging, I used molecular techniques to conduct paternity analysis as a proxy of how far pollen is carried away from particular trees within a population of Senegalia (Acacia) mellifera. The paternity analysis showed that pollinators move on average a maximum of 60 metres from the sampled trees, and that trees producing more flowers (resources) receive more visits, confirming that if sufficient resources are available pollinators can stay within relatively small geographic areas. Pollen movement only provides a partial measurement of the genetic neighbourhood of individual plants, because genes via seed dispersal can travel longer distances than those encompassed by the pollinators foraging areas. To investigate patterns of genetic variability in S. mellifera, I used microsatellites to conduct landscape genetic analyses including 25 adult populations and 9 seedling populations. Fourteen distinctive genetic clusters separated by four main geographic barriers were identified in the analyses. Significantly higher inbreeding was found in the seedling populations than in the adult populations. I discuss the possibility that this situation has been caused by anthropogenic exploitation and fragmentation of the adult stands.

Les interaccions planta-pol·linitzador són un component essencial de la biodiversitat i la funció ecològica dels ecosistemes terrestres. Un dels principals objectius de l'ecologia de la pol·linització és descriure aquestes interaccions i comprendre els factors subjacents a la seva estructura. En aquesta tesi doctoral es presenten els resultats dels estudis duts a terme durant tres anys en una comunitat mediterrània de plantes i els seus insectes pol·linitzadors al parc natural del Garraf (NE Espanya). En el capítol 1 es van registrar les interaccions planta-pol·linitzador i es van mesurar diferents trets morfològics, fenològics i ecològics de les especies de plantes i pol·linitzadors en un intent d'establir quins d’aquest trets estructuren les relacions planta-pol·linitzador. Es van registrar 14.713 contactes entre les principals 23 espècies de plantes i 221 espècies de pol·linitzadors, que van representar 960 interaccions específiques. Trobem que un tret ecològic (densitat de flors) i un tret fenològic (temps de floració) de les plantes van ser els principals factors que expliquen les interaccions observades. Trets florals, com la restricció de la corol·la i el pol·len i la producció de nèctar per flor, van tenir un efecte menor. En el capítol 2 s’explora el paper d'un atribut floral diferent i complex, l’aroma floral, en l'estructuració de la variació temporal de les taxes de visites de pol·linitzadors en la mateixa comunitat. Trobem que les plantes que floreixen a principis de la temporada, en un moment en què les flors són més abundants però els pol·linitzadors són escassos, produeixen major quantitats de compostos volàtils que les plantes que floreixen més tard, quan els pol·linitzadors són molt més abundants en relació a les poques flors disponibles. Aquest és el primer estudi en el qual s'analitzen els patrons d'emissió de fragàncies florals a nivell comunitari. Finalment, al capítol 3 s'exploren amb més detall la importància d’aquestes fragàncies florals mitjançant un cas d’estudi realitzat en el Jardí Botànic i Ecològic de la Universitat de Bayreuth (Alemanya). En aquest estudi es va utilitzar una planta focal (la composta Cirsium arvense) i un dels seus pol·linitzadors principal (el sírfid Episyrphus balteatus). Mitjançant mesures de volàtils al laboratori, tècniques d’electroantenografia i bioassajos es va trobar que els senyals olfactius eren més importants que els senyals visuals com a atraients de E. balteatus cap a les inflorescències de C. arvense.
Plant-pollinator interactions are an essential component of biodiversity and ecological function in terrestrial ecosystems. One of the main objectives of pollination ecology is to describe these interactions and to understand the factors underlying their structure. In this PhD thesis we present the results of studies conducted over three years in a Mediterranean plant-pollinator community in the natural park of el Garraf (NE Spain). In chapter 1 we monitored plant-pollinator interactions and measured plant and pollinator traits in an attempt to establish the main drivers of plant-pollinator relationships. We recorded 14713 contacts between the main 23 plant species and 221 pollinator species, representing 960 specific interactions. We found that an ecological trait (flower density) and a phonological trait (flowering time) were the main factors explaining the observed interactions. Floral traits, such as corolla restrictiveness and pollen and nectar production per flower, had a lesser effect. In chapter 2 we explore the role of a different and complex floral attribute, floral scent, in structuring temporal variation in pollinator visitation rates in the same community. We found that plants blooming early in the season, at a time when flowers are most abundant but pollinators are scarce, produce larger amounts of volatiles than plants blooming later, when pollinators are plentiful for the few flowers available. This is the first study in which emission patterns are analysed at the community level. Floral fragrances are further explored in chapter 3, which describes a case study conducted at the Ecological Botanical Garden of the University of Bayreuth (Germany). This study involves a focal plant (the composite Cirsium arvense) and a focal pollinator (the syrphid fly Episyrphus balteatus), and uses laboratory volatile measurements, electroantennography techniques and biossays. We found that olfactory cues were more important than visual cues as attractants of E. balteatus to C. arvense inflorescences.

Ecological systems are inherently dynamic, and a primary way in which they are dynamic is through time. Individual organisms, populations, communities, species interactions, and ecosystem functions all follow a temporal progression from the past, to the present, and into the future. This temporal progression can occur over the course of minutes, hours, days, weeks, months, years, decades, or various other timescales. In this sense, temporal dynamics are an intrinsic property of all biological systems. In fact, one of the most prominent signals of recent global climate change is the significant change in the timing of biological events for a diversity of organisms. In light of this widespread pattern, there is a renewed interest in understanding the multifaceted importance of time in ecology. In this dissertation, I investigate the temporal ecology of a subalpine ecosystem, specifically focusing on flowering plant communities and plant-pollinator interactions. I examine the temporal dynamics of this system over multiple decades in response to ongoing climate change as well as over shorter time scales within a growing season. Using a 39-year record of flowering phenology, I show that species-specific shifts in the timing of flowering in response to climate change can substantially reshape a subalpine plant community over this time period. Community phylogenetic analyses reveal that these changes are largely independent of evolutionary history. Using a laboratory experiment, I show that the timing of an important harsh abiotic event-low temperatures that cause frost damage to plants-can differentially affect flowering plant species, with implications for plant demography, community structure, and interactions with pollinators. Finally, I show that plant-pollinator interactions exhibit substantial within-season temporal turnover, and that this temporal flexibility of plant-pollinator interactions from one week to the next is consistent and predictable across years. Taken together, this dissertation provides a multifaceted investigation of the temporal ecology of plant communities and plant-pollinator interactions, revealing the important consequences of ecological timing at short-term and longer-term scales.

La grande majorité des plantes à fleurs se reproduisent grâce à leurs pollinisateurs. L’évolution chez les plantes est pourtant souvent étudiée sans prendre en compte ces interactions, et cette thèse vise à mieux comprendre leur impact sur l’évolution des plantes. Dans un premier chapitre, je présenterai les effets connus des pollinisateurs sur le taux d’autofécondation des plantes et sur son évolution. Dans un second chapitre, j’ai modélisé l’évolution du taux d’autofécondation des plantes lorsque celui-ci affecte la démographie des plantes et des pollinisateurs, et l’investissement des plantes dans la pollinisation. Cette étude montre que l’évolution vers l’autofécondation peut mener à l’extinction des plantes. Dans un troisième chapitre, je m’intéresserai à l’évolution des caractéristiques florales pour des espèces qui dépendent obligatoirement du transfert de pollen entre individus : les espèces dioïques. Cette étude montre que l’attractivité des plantes peut évoluer différemment chez les individus mâles et femelles, surtout dans les grandes populations qui subissent peu de limitation en pollen. Ce résultat suggère que le dimorphisme sexuel ne menacerait pas le maintien des populations dioïques. Enfin, même si elles prennent en compte les pollinisateurs de manière sommaire, les études précédentes ont montré leur importance pour la démographie et l’évolution chez les plantes. La dernière étude de cette thèse a donc pour but de mieux décrire et quantifier les mécanismes sous-jacents au comportement du pollinisateur, en particulier concernant l’impact des traits floraux. Elle permettra une meilleure intégration des interactions plantes-pollinisateurs dans les modèles
The mode of pollination is often neglected regarding the evolution of plant traits, although the reproduction of most flowering plants is based on their interactions with pollinators. This thesis aims at a better understanding of the interplay between animal-pollination and the evolution of plant traits. First, I will present a detailed review on the interplay between plant mating system and pollinator behavior, which highlights the impact of pollinators on the immediate ecological selfing rate and on its evolution. Second, I modeled the evolution of plant selfing rate when it affects both the demography of plants and pollinators and the investment of plants in pollination. This study provides new theoretical evidence that evolution towards selfing can lead to an evolutionary suicide in some conditions. Third, I will present a modeling analysis of the impact of animal-pollination for species that compulsorily rely on outcross pollination: entomophilous dioecious species. This study revealed that under pollinator-mediated selection, attractiveness of males and females should evolve in large populations that do not suffer from pollen limitation. This result suggests that dimorphism may not be a threat for dioecious populations. Finally, although the previous models integrated pollinators in a basic way, they highlighted strong interplays between pollinators, plant demography, and the evolution of plant traits. The last study of this thesis, aims at defining and quantifying the mechanisms underlying pollinator foraging behavior, and especially the impact of plants floral traits on pollen transfer. This would allow for a better modeling of plant-pollinators interactions

Bumble bees are important pollinators of both crops and wildflowers and t heir foraging behaviour greatly affects pollination interactions. The ability to predict these interactions can be improved by understanding the factors influencing bumble bee foraging choices. One method that has been applied to bumble bee foraging with some success is the use of optimal foraging theory to predict and understand foraging choices. This study has used optimal foraging theory in an attempt to explore a number of key assumptions and factors related to bumble bee foraging: whether net rate or efficiency maximisation is a more appropriate currency for modelling bumble bees; examining the preferences of bumble bees to identify factors which may influence the accuracy of their prediction; investigating how models based on different assumptions predict bumble bee distribution across adjacent habitats; and exploring how bumble bee body mass influences flower choice and foraging behaviour. The findings of this study are discussed in terms of predicting pollinator behaviour and its impact on plant -pollinator interactions.

Neste trabalho avaliámos o impacto que a perturbação humana das comunidades da floresta nativa da ilha Terceira (Açores) tem sobre a riqueza específica e nas interações ecológicas entre plantas e polinizadores. Para o efeito selecionámos dois locais emparelhados (um bem conservado e outro degradado), em duas áreas de estudo (Lomba e Pico Galhardo) e analisámos a integridade das redes ecológicas planta-polinizador. Constatámos que nas áreas bem conservadas as interações são dominadas por espécies nativas, enquanto que nas áreas perturbadas, apesar da prevalência de plantas introduzidas, os polinizadores nativos têm um papel relevante. Em cada área houve apenas uma planta que concentrou as visitas dos polinizadores, que na sua maioria pertenceram à ordem Diptera e tiveram hábitos generalistas; Biodiversity and plant-pollinator interactions in native forest areas of Terceira island (Azores) Abstract: In this work we evaluate the effect of anthropogenic disturbance in native forest communities of Terceira island (Azores) on species richness and on plant-pollinator ecological interactions. We selected paired sampling sites (one well-preserved and one disturbed) in two study areas (Lomba and Pico Galhardo) and we analysed plant-pollinator networks integrity. We found that native species dominate in well-preserved sites whereas in disturbed sites, despite the prevalence of introduced plants, native pollinators play an important role. In each area there was a plant that received most of the insect visits, being these mainly from Diptera order and having generalist behaviour.

Els patrons de variabilitat espacial en comunitats naturals han sigut habitualment estudiats en escales espacials grans, comparant hàbitats, on la distribució d’espècies està bàsicament relacionada amb factors ambientals. Tot i això, dintre un hàbitat és possible trobar variabilitat espacial a petita escala. La variació en la ocurrència i l’abundància de les espècies al llarg de l’espai afectarà l’estructura de les interaccions ja que diferents espècies varien en les seves característiques i amb el nombre i identitat de les espècies amb qui poden interactuar. La variabilitat espacial en les comunitats pot tenir també conseqüències ecològiques i evolutives ja que la variació en la distribució de les espècies afecta el funcionament dels ecosistemes. La pol·linització és un procés clau als ecosistemes terrestres, ja que al menys el 90% de les espècies d’angiospermes depenen de la pol·linització per animals. L’objectiu general d’aquesta tesi és analitzar la relació entre l’estructura de les comunitats planta-pol·linitzador, la funció ecosistèmica, i els patrons d’interacció al llarg de l’espai. Primer, volem veure el grau de variabilitat espacial a escala local en una comunitat planta-pol·linitzador en un hàbitat uniforme i entendre els factors afectant la variabilitat. Amb tal fi analitzem l’heterogeneïtat espacial d’una comunitat de plantes i els seus pol·linitzadors en un matollar mediterrani. Mostrem que, tot i l’aparent uniformitat, tant flors com pol·linitzadors mostren uns alts nivells de variabilitat resultant en un mosaic de comunitats locals. Els recursos no són limitants, i l’abella de la mel no afecta la distribució de la comunitat de pol·linitzadors silvestres. En general mostrem que la variabilitat de la comunitat floral no és el major predictor de la comunitat de pol·linitzadors, indicant que altres factors són importants per explicar la distribució dels pol·linitzadors a escala local. Segon, ens aprofitem de la variabilitat espacial en la comunitat de pol·linitzadors en el mateix matollar mediterrani i analitzem els efectes en la funció pol·linitzadora i l’èxit reproductiu de l’espècie ginodioica Thymus vulgaris. La deposició de pol·len es veu afectada per l’estructura de la comunitat de pol·linitzadors en els dos morfs, però no hem trobat efecte dels pol·linitzadors en l’èxit reproductiu de cap dels dos morfs indicant que la pol·linització és adequada en la majoria de poblacions estudiades. El nostre estudi mostra que la variabilitat local en la composició dels pol·linitzadors pot tenir conseqüències importants en la funció pol·linitzadora, especialment en les plantes que són més dependents dels pol·linitzadors. Finalment estudiem si hi ha una relació entre les característiques florals i les visites dels pol·linitzadors en comunitats naturals, centrant-nos en el color. Tot i que els pol·linitzadors presenten preferències de color innates, la idea de que els colors d’una flor poden ser un predictor important dels seus principals pol·linitzadors és molt controvertit ja que l’elecció de flor és dependent del context. Trobem associacions consistents entre grups de pol·linitzadors i determinats colors, i aquestes associacions coincideixen amb les predites per la teoria dels síndromes de pol·linització. Tot i això, les flors amb colors similars no atreuen assemblatges de pol·linitzadors similars. L’explicació d’aquest resultat paradoxal seria que la majoria d’espècies de flors són generalistes. Veiem que a pesar de que les preferències de color dels pol·linitzadors sembla que condicionin les interaccions planta-pol·linitzador, les forces selectives sota aquestes preferències no són suficientment fortes com per mediar l’aparició i manteniment d’associacions estretes entre plantes i pol·linitzadors basades en el color.
Los patrones de variabilidad espacial en comunidades naturales han sido habitualmente estudiados en escalas espaciales grandes, comparando hábitats, donde la distribución de especies está básicamente relacionada con factores ambientales. Aun así, dentro de un hábitat es posible encontrar variabilidad espacial a pequeña escala. La variación en la ocurrencia y abundancia de las especies a lo largo del espacio afectará la estructura de las interacciones ya que las diferentes especies varían en sus características y en el nombre e identidad de las especies con quien pueden interactuar. La variabilidad espacial en las comunidades puede tener también consecuencias ecológicas y evolutivas ya que la variación en la distribución de las especies afecta el funcionamiento de los ecosistemas. La polinización es un proceso clave en los ecosistemas terrestres, donde al menos el 90% de las especies de angiospermas dependen de la polinización por animales. El objetivo general de esta tesis es analizar la relación entre la estructura de las comunidades planta-polinizador, la función ecosistémica y los patrones de interacción a lo largo del espacio. Primero, queremos ver el grado de variabilidad espacial a escala local en una comunidad planta-polinizador en un hábitat uniforme y entender los factores que afectan dicha variabilidad. Con tal objetivo analizamos la heterogeneidad espacial de una comunidad de plantas y sus polinizadores en un matorral mediterráneo. Mostramos que, a pesar de la aparente uniformidad, tanto flores como polinizadores muestran unos elevados niveles de variabilidad resultando en un mosaico de comunidades locales. Los recursos no son limitantes, y la abeja de la miel no afecta la distribución de las comunidades de polinizadores silvestres. En general mostramos que la variabilidad en la comunidad floral no es el mayor predictor de la comunidad de polinizadores, indicando que otros factores son más importantes para explicar la distribución de los polinizadores a escala local. Segundo, aprovechamos la variabilidad espacial en la comunidad de polinizadores en el mismo matorral mediterráneo y analizamos los efectos en la función polinizadora y el éxito reproductivo de la especie ginodioica Thymus vulgaris. La deposición de polen se ve afectada por la estructura de la comunidad de polinizadores en los dos morfos, pero no hemos encontrado efectos de los polinizadores en el éxito reproductivo de ninguno de los dos morfos indicando que la polinización es adecuada en la mayoría de poblaciones estudiadas. Nuestro estudio muestra que la variabilidad local en la composición de los polinizadores puede tener consecuencias importantes en la función polinizadora, especialmente en las plantas que son más dependientes de los polinizadores. Finalmente estudiamos si hay una relación entre las características florales y las visitas de los polinizadores en comunidades naturales, centrándonos en el color. Aunque los polinizadores presentan preferencias de color innatas, la idea de que el color de la flor puede ser un predictor importante de sus principales polinizadores es muy controvertida ya que la elección de flor es dependiente del contexto. Encontramos asociaciones consistentes entre grupos de polinizadores y ciertos colores, y estas asociaciones coinciden con las predichas por la teoría de los síndromes de polinización. Aun así, las flores con colores similares no atraen ensamblajes de polinizadores similares. La explicación de este resultado paradójico seria que la mayoría de especies de flores son generalistas. Vemos que a pesar de que las preferencias de color de los polinizadores parece que condicionen las interacciones planta-polinizador, las fuerzas selectivas bajo estas preferencias no son suficientemente fuertes como para mediar la aparición y mantenimiento de asociaciones estrechas entre plantas y sus polinizadores basadas en el color.
Patterns of spatial variation in species communities have been usually studied at large spatial scales, comparing different habitats, where the distribution of species is mostly related to environmental factors. However, even within a habitat is possible to find important levels of spatial variability at the local scale. Variability in species occurrence and abundance across space will affect interaction structure because species differ in their functional traits and therefore in the number and identity of species with which they may interact. Furthermore, within-habitat spatial heterogeneity in species community structure may have far-reaching ecological and evolutionary consequences because variability in the spatial distribution of the species affects the functioning of ecosystems. Pollination is a key function in terrestrial ecosystems, with almost 90% of the angiosperm species depending on animal pollinators for sexual reproduction. The general objective of this thesis is to analyze the relationship between plant-pollinator community structure, ecological function, and interaction patterns across space. First, we aim to highlight the degree of spatial variation at the local scale in a plant-pollinator community across a uniform habitat and to understand the deterministic factors affecting this variation. For this purpose we analyse the spatial heterogeneity of a community of flowering plants and their pollinators within an uninterrupted Mediterranean scrubland. Also, since the study area is a honey producing area we want to know whether wild pollinator communities were affected by honey bee abundance. We show that, in spite of the apparent physiognomic uniformity, both flowers and pollinators display high levels of heterogeneity, resulting in a mosaic of idiosyncratic local communities. Resources appear to be non-limiting, and honey bee visitation rate did not affect the distribution of the wild pollinator community. Overall, our results show that the spatial variation of the flower community is not the main predictor of the pollinator community, indicating that other factors besides flower community composition are important to explain pollinator distribution at the local scale. Second, we take advantage of the spatial variability in local pollinator community across the same Mediterranean scrubland and analyse its effects on pollination function and reproductive success in the gynodioecious Thymus vulgaris. Pollen deposition is affected by pollinator assemblage structure and composition in both morphs, but we found no effect of the pollinator assemblage on plant reproductive success in either of the two morphs, showing that pollination appears to be adequate in most of the populations sampled. Our study shows that local variation in pollinator composition may have important consequences on pollination function, especially on plants that are more dependent on pollinators. Finally, we aim to establish whether there is a relationship between floral traits and pollinator visitation in natural communities, specifically focusing on floral colour. Although pollinators show innate colour preferences, the view that the colour of a flower may be considered an important predictor of its main pollinators is highly controversial because flower choice is highly context-dependent. We found consistent associations between pollinator groups and certain colours, and these associations matched predictions of the pollination syndrome theory. However, flowers with similar colours did not attract similar pollinator assemblages. The explanation for this paradoxical result is that most flower species are pollinator generalists. We conclude that although pollinator colour preferences seem to condition plant-pollinator interactions, the selective force behind these preferences has not been strong enough to mediate the appearance and maintenance of tight colour-based plant-pollinator associations.

Both animal and plant species exhibit adaptive traits related to features of mediterranean-type ecosystems (MTEs). For plants, the seasonality of the MTC has been an important factor in the evolution of plant phenological traits. Root adaptive traits that improve nutrient extraction from impoverished soils are present within MTC regions, including cluster roots, root nodules, and mycorrhizal symbioses. Fire has been an important driver of plant traits, such as smoke, charate, or heat-induced seed germination or seed release (i.e. serotiny), and post-fire flowering. Adaptive traits in animals include both physiological and behavioural traits. MTC regions have been used in the study of many ecological and evolutionary patterns, particularly as related to organismal adaptations to unique soil and substrates (edaphic communities) and interactions between plants and animals, such as plant–herbivore interactions, plant–pollinator interactions, and plant–seed disperser interactions. These interactions shape many plant and animal characters within MTC regions.

The Flowering of Australia's Rainforests provides an overview of pollination in Australian rainforests, especially subtropical rainforests. It also examines the plant-pollinator relationships found in rainforests worldwide. The Flowering of Australia's Rainforests progresses through introductory and popular sections that cover pollination in lore and legend; plant and flower evolution and development; and the role and function of colour, fragrance and form. Later chapters deal with breeding systems; mimicry; spatial, temporal and structural influences on plant-pollinator interactions; and a discussion and overview of floral syndromes. The book concludes with a section on conservation and fragmentation, and individual plant pollination case studies. Illustrated with colour photographs of major species, this reference work will be treasured by field naturalists, ecologists, conservation biologists, botanists, ecosystem managers, environmentalists, community groups and individuals involved in habitat restoration, students, and those with a broad interest in natural history.

The book is devoted to the problems of preserving the biodiversity of insects and pollinators through the use of inoffensive methods of agricultural crops cultivating and bio-rational means of protecting them from pests and diseases in an ecological crisis. The results of many years of research on the development of technological processes for obtaining biological preparations based on secondary metabolites of higher plants and microorganisms are presented. Their effectiveness in increasing the resistance of cultivated plants to the influences of abiotic and biotic environmental factors has been shown. The results of plant extracts testing with biopesticidal activity against insects and mites-phytophages and as growth regulators of vegetable and cereal crops are presented. The characteristic features of the interaction of useful fauna organisms and pests of agricultural crops, as well as the possibility of attracting pollinators through the use of semiochemicals are described. The mechanisms of microbiological preparations action and their effectiveness against phytopathogens are revealed. The prospects of biological preparations introducing for a gentle impact on the environment and beneficial insects, as well as obtaining safe food products, have been demonstrated. The book is intended for farmers and beekeepers, and can be used as a teaching aid in various courses on ecology, biology, plant protection and entomology.

The book is devoted to the problems of preserving the biodiversity of insects and pollinators through the use of inoffensive methods of agricultural crops cultivating and bio-rational means of protecting them from pests and diseases in an ecological crisis. The results of many years of research on the development of technological processes for obtaining biological preparations based on secondary metabolites of higher plants and microorganisms are presented. Their effectiveness in increasing the resistance of cultivated plants to the influences of abiotic and biotic environmental factors has been shown. The results of plant extracts testing with biopesticidal activity against insects and mites-phytophages and as growth regulators of vegetable and cereal crops are presented. The characteristic features of the interaction of useful fauna organisms and pests of agricultural crops, as well as the possibility of attracting pollinators through the use of semiochemicals are described. The mechanisms of microbiological preparations action and their effectiveness against phytopathogens are revealed. The prospects of biological preparations introducing for a gentle impact on the environment and beneficial insects, as well as obtaining safe food products, have been demonstrated. The book is intended for farmers and beekeepers, and can be used as a teaching aid in various courses on ecology, biology, plant protection and entomology.

Abstract There has been growing interest in the consequences of invasive non-native plants for the plant-pollinator mutualism, most likely because of its relevance for the maintenance of terrestrial biodiversity and food production. However, the development of this research field has been thematically uneven and the overall evidence inconclusive. Many studies have focused on how non-native plants interact with native plants via pollinator sharing, which have allowed meta-analytical syntheses, whereas several others have looked at how frequently non-native plants integrate into native plant-pollinator webs and how they affect network structure. However, relatively few studies have addressed the consequences of invasive plants for pollinators. Overall, the research approach in this area has been predominantly phenomenological rather than mechanistic, which has hindered our understanding of apparently contradictory evidence. One key characteristic of invasive non-native plants that seems to mediate negative effects on the pollination mutualism is the high relative abundance that they reach at late stages of invasion. This high dominance is apparently the main trigger of all the disruptive direct and indirect effects that are discussed in this chapter. Finally, we identify several intriguing questions on the ecological and evolutionary consequences of invasive plants for the plant-pollinator mutualism waiting to be answered.

Abstract Invasive plant species degrade and homogenize ecosystems worldwide, thereby altering ecosystem processes and function. To mitigate and reverse the impact of invasive plants on pollination, a key ecosystem function, conservation scientists and practitioners restore ecological communities and study the impact of such management interventions on plant-pollinator communities. Here, we describe opportunities and challenges associated with restoring pollination interactions as part of a holistic ecosystem-based restoration approach. We introduce a few general concepts in restoration ecology, and outline best planning and evaluation practices of restoring pollination interactions on the community level. Planning involves the selection of suitable plant species to support diverse pollinator communities, which includes considerations of the benefits and disadvantages of using native vs exotic, and bridge and framework plant species for restoration. We emphasize the central role of scientific- and community-level approaches for the planning phase of pollination restoration. For evaluation purposes, we argue that appropriate network indicators have the advantage of detecting changes in species behaviour with consequences for ecosystem processes and functions before these changes show up in altered species communities. Suitable network metrics may include interaction diversity and evenness, and network measures that describe the distribution of species, such as network and species-level specialization, modularity and motifs. Finally, we discuss the usefulness of the network approach in evaluating the benefits of restoration interventions for pollination interactions, and propose that applied network ecologists take a central role in transferring theory into practice.

Abstract Invasive plants often occur at high densities and tend to be highly generalist in their interactions with herbivores, pathogens, mycorrhiza, endophytes and pollinators. These characteristics mean that invasive plants should frequently participate in diverse indirect biotic interactions with the surrounding community, mediated by their direct interaction partners (e.g. antagonists and mutualists). Indirect interactions play an important role in many ecological processes, yet we still lack a systematic understanding of the circumstances under which they influence the success and impacts of invasive species. In this chapter, I first describe several of the indirect interaction pathways that are commonly encountered in invasion biology and review their contribution to the impacts of plant invasions on co-occurring species. The literature review revealed that there are now many case studies describing various indirect impacts of invasive plants. However, identical interaction motifs (e.g. plant-enemy-plant, plant-mutualist-plant) can bring about several possible outcomes, depending upon each species' provenance, relative abundances and interaction strengths, abiotic resource availability, spatial and temporal scale and the influence of other species. Moreover, knowledge gaps identified include a lack of studies of indirect facilitation outside of plant-pollinator systems, limited consideration of indirect invader impacts on other non-native species, and the scarcity of generalizable results to date. Second, I integrate the literature with some trending research areas in invasion biology (interaction networks, biogeography, invasion dynamics) and identify some potential future research directions. Finally, I discuss how knowledge about indirect biotic interactions could be incorporated into the management of invasive plants.

Pollination is an imperative biological process, and the exotic plant species have a significant effect on the interaction of plant with pollinators. The exotic plant communities have the ability to cause both direct and indirect impacts on pollinators. The impact of non-native exotic plants on native pollinators can occur at a varying range of scales: starting from the flower visitors who visit flowers individually, to populations and community-level interactions (insect-flower interaction networks). As it is impractical to study every invasive plant in every ecological context, understanding appropriate individual-level trait predicting direct interactions between invasive exotic plants and native pollinators is needed.

There has been growing interest in the consequences of invasive non-native plants for the plant-pollinator mutualism, most likely because of its relevance for the maintenance of terrestrial biodiversity and food production. However, the development of this research field has been thematically uneven and the overall evidence inconclusive. Many studies have focused on how non-native plants interact with native plants via pollinator sharing, which have allowed meta-analytical syntheses, whereas several others have looked at how frequently non-native plants integrate into native plant-pollinator webs and how they affect network structure. However, relatively few studies have addressed the consequences of invasive plants for pollinators. Overall, the research approach in this area has been predominantly phenomenological rather than mechanistic, which has hindered our understanding of apparently contradictory evidence. One key characteristic of invasive non-native plants that seems to mediate negative effects on the pollination mutualism is the high relative abundance that they reach at late stages of invasion. This high dominance is apparently the main trigger of all the disruptive direct and indirect effects that are discussed in this chapter. Finally, we identify several intriguing questions on the ecological and evolutionary consequences of invasive plants for the plant-pollinator mutualism waiting to be answered.

The term “plant-animal interactions” includes a diverse array of biologically important relationships. Plant-herbivore relationships (in which an animal feeds on whole plants or parts of them) are examples of exploitation, because one species benefits from the interaction while the other suffers. Plant-pollinator and plant-seed disperser relationships (in which animals disperse pollen or seeds, usually in return for a food reward) are examples of mutualisms because they are beneficial to both parties. Another class of plant-animal mutualisms involves plants that provide nesting sites and/or food rewards to ants, which often protect the plant from herbivores or competing plants. Plantpollinator and plant-seed disperser mutualisms probably originated as cases of exploitation of plants by animals (Thompson 1982, Crepet 1983, Tiffney 1986). Many of the distinctive plant structures associated with animal-mediated pollen and seed dispersal (e.g., flowers, nectaries, attractive odors, fleshy fruit pulp, and thickened seed coats) presumably evolved to attract consumers of floral or seed resources while preventing them from digesting the pollen or seeds. mutualisms in structuring ecological communities. Competition and predator-prey interactions were more common subjects. Botanists had described the characteristics of the plant and animal players in pollination and seed dispersal mutualisms (Knuth 1906, 1908, 1909, Ridley 1930, van der Pijl 1969, Faegri and van der Pijl 1979), but these descriptive works did not fully examine plant-animal mutualisms in the context of communities. The opportunity to work in the neotropics, facilitated by the Organization for Tropical Studies (OTS), the Smithsonian Tropical Research Institute (STRI), and other institutions, attracted the attention of temperate-zone ecologists to the mutualisms that are much more conspicuous components of tropical systems than of temperate ones (Wheelwright 1988b). Plant-pollinator interactions have attracted more attention in Monteverde than plant-frugivore interactions, and plant-herbivore interactions remain conspicuously understudied. This imbalance probably reflects the interests of those who first worked at Monteverde and later returned with their own students, rather than differences in the significance of the interactions at Monteverde or elsewhere. Aside from a few studies of herbivory in particular species (e.g., Peck, “Agroecology of Prosapia,”), even basic surveys remain to be done.

During the evolutionary process of speciation in plants, naturally occurring barriers to reproduction have developed that affect the transfer of genes within and between related species. These barriers can occur at several different levels beginning with pollination-barriers and ending with hybrid-breakdown. The interaction between pollen and pistils presents one of the major barriers to intra- and inter-specific crosses and is the focus of this research project. Our long-term goal in this research proposal was defined to resolve questions on recognition and communication during pollen-pistil interactions in the extended tomato family. In this context, this work was initiated and planned to study the potential involvement of tomato pollen-specific receptor-like kinases (RLK's) in the interaction between pollen and pistils. By special permission from BARD the objectives of this research were extended to include studies on pollen-pistil interactions and pollination barriers in horticultural crops with an emphasis on citrus. Functional characterization of 2 pollen-specific RLK's from tomato was carried out. The data shows that both encode functional kinases that were active as recombinant proteins. One of the kinases was shown to accumulate mainly after pollen germination and to be phosphorylated in-vitro in pollen membranes as well as in-vivo. The presence of style extract resulted in dephosphorylation of the RLK, although no species specificity was observed. This data implies a role for at least one RLK in pollination events following pollen germination. However, a transgenic plant analysis of the RLK's comprising overexpression, dominant-negative and anti-sense constructs failed to provide answers on their role in pollination. While genetic effects on some of the plants were observed in both the Israeli and American labs, no clear functional answers were obtained. An alternative approach to addressing function was pursued by screening for an artificial ligand for the receptor domain using a peptide phage display library. An enriched peptide sequence was obtained and will be used to design a peptide-ligand to be tested for its effect o pollen germination and tube growth. Self-incompatibility (SI) in citrus was studied on 3 varieties of pummelo. SI was observed using fluorescence microscopy in each of the 3 varieties and compatibility relations between varieties was determined. An initial screen for an S-RNase SI mechanism yielded only a cDNA homologous to the group of S-like RNases, suggesting that SI results from an as yet unknown mechanism. 2D gel electrophoresis was applied to compare pollen and style profiles of different compatibility groups. A "polymorphic" protein band from style extracts was observed, isolated and micro-sequenced. Degenerate primers designed based on the peptide sequence date will be used to isolate the relevant genes i order to study their potential involvement in SI. A study on SI in the apple cultivar Top red was initiated. SI was found, as previously shown, to be complete thus requiring a compatible pollinator variety. A new S-RNase allele was discovered fro Top red styles and was found to be highly homologous to pear S-RNases, suggesting that evolution of these genes pre-dated speciation into apples and pears but not to other Rosaceae species. The new allele provides molecular-genetic tools to determine potential pollinators for the variety Top red as well as a tool to break-down SI in this important variety.