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Florian P. Schiestl - One of the best experts on this subject based on the ideXlab platform.
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the evolution of floral scent the influence of olfactory learning by insect Pollinators on the honest signalling of floral rewards
Functional Ecology, 2009Co-Authors: Geraldine A Wright, Florian P. SchiestlAbstract:1. The evolution of flowering plants has undoubtedly been influenced by a pollinator's ability to learn to associate floral signals with food. Here, we address the question of 'why' flowers produce scent by examining the ways in which olfactory learning by insect Pollinators could influence how floral scent emission evolves in plant populations. 2. Being provided with a floral scent signal allows Pollinators to learn to be specific in their foraging habits, which could, in turn, produce a selective advantage for plants if sexual reproduction is limited by the income of compatible gametes. Learning studies with honeybees predict that pollinator-mediated selection for floral scent production should favour signals which are distinctive and exhibit low variation within species because these signals are learned faster. Social bees quickly learn to associate scent with the presence of nectar, and their ability to do this is generally faster and more reliable than their ability to learn visual cues. 3. Pollinators rely on floral scent as a means of distinguishing honestly signalling flowers from deceptive ones. Furthermore, a pollinator's sensitivity to differences in nectar rewards can bias the way that it responds to floral scent. This mechanism may select for flowers that provide olfactory signals as an honest indicator of the presence of nectar or which select against the production of a detectable scent signal when no nectar is present. 4. We expect that an important yet commonly overlooked function of floral scent is an improvement in short-term pollinator specificity which provides an advantage to both pollinator and plant over the use of a visual signal alone. This, in turn, impacts the evolution of plant mating systems via its influence on the species-specific patterns of floral visitation by Pollinators.
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how to be an attractive male floral dimorphism and attractiveness to Pollinators in a dioecious plant
BMC Evolutionary Biology, 2009Co-Authors: M Waelti, Paul Page, Alex Widmer, Florian P. SchiestlAbstract:Sexual selection theory predicts that males are limited in their reproductive success by access to mates, whereas females are more limited by resources. In animal-pollinated plants, attraction of Pollinators and successful pollination is crucial for reproductive success. In dioecious plant species, males should thus be selected to increase their attractiveness to Pollinators by investing more than females in floral traits that enhance pollinator visitation. We tested the prediction of higher attractiveness of male flowers in the dioecious, moth-pollinated herb Silene latifolia, by investigating floral signals (floral display and fragrance) and conducting behavioral experiments with the pollinator-moth, Hadena bicruris. As found in previous studies, male plants produced more but smaller flowers. Male flowers, however, emitted significantly larger amounts of scent than female flowers, especially of the pollinator-attracting compounds. In behavioral tests we showed that naive pollinator-moths preferred male over female flowers, but this preference was only significant for male moths. Our data suggest the evolution of dimorphic floral signals is shaped by sexual selection and pollinator preferences, causing sexual conflict in both plants and Pollinators.
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Floral Isolation, Specialized Pollination, and Pollinator Behavior in Orchids
Annual review of entomology, 2009Co-Authors: Florian P. Schiestl, Philipp M. SchlüterAbstract:Floral isolation is a form of prepollination reproductive isolation mediated by floral morphology (morphological isolation) and pollinator behavior (ethological isolation). Here we review mechanisms and evolutionary consequences of floral isolation in various pollination systems. Furthermore, we compare key features of floral isolation, i.e., pollinator sharing and specialization in pollination, in different orchid pollination systems. In orchid pollination, pollinator sharing is generally low, indicating strong floral isolation. The Pollinators' motivation to visit flowers (specifically) can be due to both foraging or reproductive behavior. In both types of behavior, innate preferences for floral signals can be quickly overruled by learning. In pollination systems in which reproductive behavior of Pollinators triggers flower visits, lower pollinator sharing was evident compared with systems with foraging behavior, probably because Pollinators displaying reproductive behavior show higher fidelity in their visitation patterns. Orchids pollinated through reproductive behavior also use fewer Pollinators than orchids pollinated through foraging behavior. No association between specialization and pollinator sharing was found. Thus, generalized pollination does not impede floral isolation, as orchids with many Pollinators may nonetheless have low pollinator sharing. Specialization in pollination was, however, linked to orchid species richness in our analysis. Flower size, spur, and column morphology are most important for morphological isolation, and floral scent is most important for ethological isolation. These traits may be based on few genes, implying that floral isolation can be brought about by few genes of large effect.
James M. Cook - One of the best experts on this subject based on the ideXlab platform.
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parasites and mutualism function measuring enemy free space in a fig pollinator symbiosis
Oikos, 2012Co-Authors: Sarah Albeidh, Derek W. Dunn, Sally A. Power, James M. CookAbstract:Mutualisms involve cooperation between species and underpin several ecosystem functions. However, there is also conflict between mutualists, because their interests are not perfectly aligned. In addition, most mutualisms are exploited by parasites. Here, we study the interplay between cooperation, conflict and parasitism in the mutualism between fig trees and their pollinator wasps. Conflict occurs because each fig ovary can nurture either one seed or one pollinator offspring and, while fig trees benefit directly from seeds and pollinator offspring (pollen vectors), Pollinators only benefit directly from pollinator offspring. The mechanism(s) of conflict resolution is debated, but must explain the widespread observation that Pollinators develop in inner, and seeds in outer, layers of fig flowers. We recently suggested a role for non-pollinating figs wasps (NPFWs) that are natural enemies or competitors of the Pollinators and lay their eggs through the fig wall. Most NPFW offspring develop in outer and middle layer flowers, suggesting that inner flowers provide enemy-free space for pollinator offspring. Here, we test the hypothesis that NPFWs cannot reach inner flowers, by measuring wasp and fig morphology at the species-specific times of NPFW attack in the field. We found that three species of Sycoscapter and Philotrypesis wasps that parasitise Pollinators could reach 34–73%, 75–92% and 82–97% of fig ovaries, respectively. Meanwhile, Eukobelea and Pseudidarnes gall-formers, despite having shorter ovipositors, can access almost all fig flowers (93–99% and 100%), because they attack smaller (younger) fig fruits. Our mechanistic results from ovipositing wasps support spatial patterns of wasp offspring segregation within figs to suggest that inner ovules provide enemy-free-space for Pollinators. This may contribute to mutualism stability by helping select for Pollinators to avoid laying eggs where they are likely to be parasitised. These outer flowers then remain free to develop as seeds, promoting mutualism persistence.
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Parasites and mutualism function: measuring enemy-free space in a fig–pollinator symbiosis
Oikos, 2012Co-Authors: Sarah Al-beidh, Derek W. Dunn, Sally A. Power, James M. CookAbstract:Mutualisms involve cooperation between species and underpin several ecosystem functions. However, there is also conflict between mutualists, because their interests are not perfectly aligned. In addition, most mutualisms are exploited by parasites. Here, we study the interplay between cooperation, conflict and parasitism in the mutualism between fig trees and their pollinator wasps. Conflict occurs because each fig ovary can nurture either one seed or one pollinator offspring and, while fig trees benefit directly from seeds and pollinator offspring (pollen vectors), Pollinators only benefit directly from pollinator offspring. The mechanism(s) of conflict resolution is debated, but must explain the widespread observation that Pollinators develop in inner, and seeds in outer, layers of fig flowers. We recently suggested a role for non-pollinating figs wasps (NPFWs) that are natural enemies or competitors of the Pollinators and lay their eggs through the fig wall. Most NPFW offspring develop in outer and middle layer flowers, suggesting that inner flowers provide enemy-free space for pollinator offspring. Here, we test the hypothesis that NPFWs cannot reach inner flowers, by measuring wasp and fig morphology at the species-specific times of NPFW attack in the field. We found that three species of Sycoscapter and Philotrypesis wasps that parasitise Pollinators could reach 34–73%, 75–92% and 82–97% of fig ovaries, respectively. Meanwhile, Eukobelea and Pseudidarnes gall-formers, despite having shorter ovipositors, can access almost all fig flowers (93–99% and 100%), because they attack smaller (younger) fig fruits. Our mechanistic results from ovipositing wasps support spatial patterns of wasp offspring segregation within figs to suggest that inner ovules provide enemy-free-space for Pollinators. This may contribute to mutualism stability by helping select for Pollinators to avoid laying eggs where they are likely to be parasitised. These outer flowers then remain free to develop as seeds, promoting mutualism persistence.
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spatial stratification of internally and externally non pollinating fig wasps and their effects on pollinator and seed abundance in ficus burkei
International Scholarly Research Notices, 2012Co-Authors: Sarah Albeidh, Derek W. Dunn, James M. CookAbstract:Fig trees (Ficus spp.) are pollinated by tiny wasps that enter their enclosed inflorescences (syconia). The wasp larvae also consume some fig ovules, which negatively affects seed production. Within syconia, pollinator larvae mature mostly in the inner ovules whereas seeds develop mostly in outer ovules—a stratification pattern that enables mutualism persistence. Pollinators may prefer inner ovules because they provide enemy-free space from externally ovipositing parasitic wasps. In some Australasian Ficus, this results in spatial segregation of pollinator and parasite offspring within syconia, with parasites occurring in shorter ovules than Pollinators. Australian figs lack non-pollinating fig wasps (NPFW) that enter syconia to oviposit, but these occur in Africa and Asia, and may affect mutualist reproduction via parasitism or seed predation. We studied the African fig, F. burkei, and found a similar general spatial pattern of Pollinators and NPFWs within syconia as in Australasian figs. However, larvae of the NPFW Philocaenus barbarus, which enters syconia, occurred in inner ovules. Philocaenus barbarus reduced pollinator abundance but not seed production, because its larvae replaced Pollinators in their favoured inner ovules. Our data support a widespread role for NPFWs in contributing to factors preventing host overexploitation in fig-pollinator mutualisms.
Anne C. Gaskett - One of the best experts on this subject based on the ideXlab platform.
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Orchid pollination by sexual deception: Pollinator perspectives
Biological Reviews, 2011Co-Authors: Anne C. GaskettAbstract:The extraordinary taxonomic and morphological diversity of orchids is accompanied by a remarkable range of Pollinators and pollination systems. Sexually deceptive orchids are adapted to attract specific male insects that are fooled into attempting to mate with orchid flowers and inadvertently acting as Pollinators. This review summarises current knowledge, explores new hypotheses in the literature, and introduces some new approaches to understanding sexual deception from the perspective of the duped pollinator. Four main topics are addressed: (1) global patterns in sexual deception, (2) pollinator identities, mating systems and behaviours, (3) pollinator perception of orchid deceptive signals, and (4) the evolutionary implications of pollinator responses to orchid deception, including potential costs imposed on Pollinators by orchids. A global list of known and putative sexually deceptive orchids and their Pollinators is provided and methods for incorporating pollinator perspectives into sexual deception research are provided and reviewed. At present, almost all known sexually deceptive orchid taxa are from Australia or Europe. A few sexually deceptive species and genera are reported for New Zealand and South Africa. In Central and Southern America, Asia, and the Pacific many more species are likely to be identified in the future. Despite the great diversity of sexually deceptive orchid genera in Australia, pollination rates reported in the literature are similar between Australian and European species. The typical pollinator of a sexually deceptive orchid is a male insect of a species that is polygynous, monandrous, haplodiploid, and solitary rather than social. Insect behaviours involved in the pollination of sexually deceptive orchids include pre-copulatory gripping of flowers, brief entrapment, mating, and very rarely, ejaculation. Pollinator behaviour varies within and among pollinator species. Deception involving orchid mimicry of insect scent signals is becoming well understood for some species, but visual and tactile signals such as colour, shape, and texture remain neglected. Experimental manipulations that test for function, multi-signal interactions, and pollinator perception of these signals are required. Furthermore, other forms of deception such as exploitation of pollinator sensory biases or mating preferences merit more comprehensive investigation. Application of molecular techniques adapted from model plants and animals is likely to deliver new insights into orchid signalling, and pollinator perception and behaviour. There is little current evidence that sexual deception drives any species-level selection on Pollinators. Pollinators do learn to avoid deceptive orchids and their locations, but this is not necessarily a response specific to orchids. Even in systems where evidence suggests that orchids do interfere with pollinator mating opportunities, considerable further research is required to determine whether this is sufficient to impose selection on Pollinators or generate antagonistic coevolution or an arms race between orchids and their Pollinators. Botanists, taxonomists and chemical ecologists have made remarkable progress in the study of deceptive orchid pollination. Further complementary investigations from entomology and behavioural ecology perspectives should prove fascinating and engender a more complete understanding of the evolution and maintenance of such enigmatic plant-animal interactions.
Derek W. Dunn - One of the best experts on this subject based on the ideXlab platform.
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parasites and mutualism function measuring enemy free space in a fig pollinator symbiosis
Oikos, 2012Co-Authors: Sarah Albeidh, Derek W. Dunn, Sally A. Power, James M. CookAbstract:Mutualisms involve cooperation between species and underpin several ecosystem functions. However, there is also conflict between mutualists, because their interests are not perfectly aligned. In addition, most mutualisms are exploited by parasites. Here, we study the interplay between cooperation, conflict and parasitism in the mutualism between fig trees and their pollinator wasps. Conflict occurs because each fig ovary can nurture either one seed or one pollinator offspring and, while fig trees benefit directly from seeds and pollinator offspring (pollen vectors), Pollinators only benefit directly from pollinator offspring. The mechanism(s) of conflict resolution is debated, but must explain the widespread observation that Pollinators develop in inner, and seeds in outer, layers of fig flowers. We recently suggested a role for non-pollinating figs wasps (NPFWs) that are natural enemies or competitors of the Pollinators and lay their eggs through the fig wall. Most NPFW offspring develop in outer and middle layer flowers, suggesting that inner flowers provide enemy-free space for pollinator offspring. Here, we test the hypothesis that NPFWs cannot reach inner flowers, by measuring wasp and fig morphology at the species-specific times of NPFW attack in the field. We found that three species of Sycoscapter and Philotrypesis wasps that parasitise Pollinators could reach 34–73%, 75–92% and 82–97% of fig ovaries, respectively. Meanwhile, Eukobelea and Pseudidarnes gall-formers, despite having shorter ovipositors, can access almost all fig flowers (93–99% and 100%), because they attack smaller (younger) fig fruits. Our mechanistic results from ovipositing wasps support spatial patterns of wasp offspring segregation within figs to suggest that inner ovules provide enemy-free-space for Pollinators. This may contribute to mutualism stability by helping select for Pollinators to avoid laying eggs where they are likely to be parasitised. These outer flowers then remain free to develop as seeds, promoting mutualism persistence.
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Parasites and mutualism function: measuring enemy-free space in a fig–pollinator symbiosis
Oikos, 2012Co-Authors: Sarah Al-beidh, Derek W. Dunn, Sally A. Power, James M. CookAbstract:Mutualisms involve cooperation between species and underpin several ecosystem functions. However, there is also conflict between mutualists, because their interests are not perfectly aligned. In addition, most mutualisms are exploited by parasites. Here, we study the interplay between cooperation, conflict and parasitism in the mutualism between fig trees and their pollinator wasps. Conflict occurs because each fig ovary can nurture either one seed or one pollinator offspring and, while fig trees benefit directly from seeds and pollinator offspring (pollen vectors), Pollinators only benefit directly from pollinator offspring. The mechanism(s) of conflict resolution is debated, but must explain the widespread observation that Pollinators develop in inner, and seeds in outer, layers of fig flowers. We recently suggested a role for non-pollinating figs wasps (NPFWs) that are natural enemies or competitors of the Pollinators and lay their eggs through the fig wall. Most NPFW offspring develop in outer and middle layer flowers, suggesting that inner flowers provide enemy-free space for pollinator offspring. Here, we test the hypothesis that NPFWs cannot reach inner flowers, by measuring wasp and fig morphology at the species-specific times of NPFW attack in the field. We found that three species of Sycoscapter and Philotrypesis wasps that parasitise Pollinators could reach 34–73%, 75–92% and 82–97% of fig ovaries, respectively. Meanwhile, Eukobelea and Pseudidarnes gall-formers, despite having shorter ovipositors, can access almost all fig flowers (93–99% and 100%), because they attack smaller (younger) fig fruits. Our mechanistic results from ovipositing wasps support spatial patterns of wasp offspring segregation within figs to suggest that inner ovules provide enemy-free-space for Pollinators. This may contribute to mutualism stability by helping select for Pollinators to avoid laying eggs where they are likely to be parasitised. These outer flowers then remain free to develop as seeds, promoting mutualism persistence.
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spatial stratification of internally and externally non pollinating fig wasps and their effects on pollinator and seed abundance in ficus burkei
International Scholarly Research Notices, 2012Co-Authors: Sarah Albeidh, Derek W. Dunn, James M. CookAbstract:Fig trees (Ficus spp.) are pollinated by tiny wasps that enter their enclosed inflorescences (syconia). The wasp larvae also consume some fig ovules, which negatively affects seed production. Within syconia, pollinator larvae mature mostly in the inner ovules whereas seeds develop mostly in outer ovules—a stratification pattern that enables mutualism persistence. Pollinators may prefer inner ovules because they provide enemy-free space from externally ovipositing parasitic wasps. In some Australasian Ficus, this results in spatial segregation of pollinator and parasite offspring within syconia, with parasites occurring in shorter ovules than Pollinators. Australian figs lack non-pollinating fig wasps (NPFW) that enter syconia to oviposit, but these occur in Africa and Asia, and may affect mutualist reproduction via parasitism or seed predation. We studied the African fig, F. burkei, and found a similar general spatial pattern of Pollinators and NPFWs within syconia as in Australasian figs. However, larvae of the NPFW Philocaenus barbarus, which enters syconia, occurred in inner ovules. Philocaenus barbarus reduced pollinator abundance but not seed production, because its larvae replaced Pollinators in their favoured inner ovules. Our data support a widespread role for NPFWs in contributing to factors preventing host overexploitation in fig-pollinator mutualisms.
Philipp M. Schlüter - One of the best experts on this subject based on the ideXlab platform.
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Floral Isolation, Specialized Pollination, and Pollinator Behavior in Orchids
Annual review of entomology, 2009Co-Authors: Florian P. Schiestl, Philipp M. SchlüterAbstract:Floral isolation is a form of prepollination reproductive isolation mediated by floral morphology (morphological isolation) and pollinator behavior (ethological isolation). Here we review mechanisms and evolutionary consequences of floral isolation in various pollination systems. Furthermore, we compare key features of floral isolation, i.e., pollinator sharing and specialization in pollination, in different orchid pollination systems. In orchid pollination, pollinator sharing is generally low, indicating strong floral isolation. The Pollinators' motivation to visit flowers (specifically) can be due to both foraging or reproductive behavior. In both types of behavior, innate preferences for floral signals can be quickly overruled by learning. In pollination systems in which reproductive behavior of Pollinators triggers flower visits, lower pollinator sharing was evident compared with systems with foraging behavior, probably because Pollinators displaying reproductive behavior show higher fidelity in their visitation patterns. Orchids pollinated through reproductive behavior also use fewer Pollinators than orchids pollinated through foraging behavior. No association between specialization and pollinator sharing was found. Thus, generalized pollination does not impede floral isolation, as orchids with many Pollinators may nonetheless have low pollinator sharing. Specialization in pollination was, however, linked to orchid species richness in our analysis. Flower size, spur, and column morphology are most important for morphological isolation, and floral scent is most important for ethological isolation. These traits may be based on few genes, implying that floral isolation can be brought about by few genes of large effect.
