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Stephen G. Compton - One of the best experts on this subject based on the ideXlab platform.
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Tritrophic interactions involving a dioecious fig tree, its fig pollinating wasp and fig nematodes
2019Co-Authors: Jauharlina Jauharlina, Rupe J Quinnell, Rina Sriwati, Natsumi Kanzaki, Hartati Oktarina, Stephen G. ComptonAbstract:Abstract Many species of fig trees (Ficus spp., Moraceae) have nematodes that develop inside their inflorescences (Figs). Nematodes are carried into young Figs by females of the trees’ host-specific pollinating fig wasps (Agaonidae) that enter the Figs to lay their eggs. The majority of Asian fig trees are functionally dioecious. Pollinators that enter Figs on female trees cannot reproduce and offspring of any nematodes they carry will also be trapped inside. The biology of the nematodes is diverse, but poorly understood. We contrasted the development of nematodes carried by the pollinating fig wasp Ceratosolen solmsi marchali into Figs on male and female trees of Ficus hispida in Sumatra, Indonesia. Figs were sampled from both male and female trees over a six-month period, with the nematodes extracted to record their development of their populations inside the Figs. Populations of three species of nematodes developed routinely inside Figs of both sexes: Caenorhabditis sp. (Rhabditidae), Ficophagus cf. centerae and Martininema baculum (both Aphelenchoididae). This is the first record of a Caenorhabditis sp. associated with F. hispida. Mean numbers of nematodes reached around 120-140 in both male and female Figs. These peak population sizes coincided with the emergence of the new generation of adult fig wasps in male fig trees. We conclude that Figs on female trees can support development and reproduction of some nematode species, but the absence of vectors means that their populations cannot persist beyond the lifetime of a single fig. Just like their fig wasp vectors, the nematodes cannot avoid this routine source of mortality.
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tritrophic interactions involving a dioecious fig tree its fig pollinating wasp and fig nematodes
bioRxiv, 2019Co-Authors: Jauharlina Jauharlina, Rupe J Quinnell, Rina Sriwati, Natsumi Kanzaki, Hartati Oktarina, Stephen G. ComptonAbstract:Many species of fig trees (Ficus spp., Moraceae) have nematodes that develop inside their inflorescences (Figs). Nematodes are carried into young Figs by females of the trees’ host-specific pollinating fig wasps (Agaonidae) that enter the Figs to lay their eggs. The majority of Asian fig trees are functionally dioecious. Pollinators that enter Figs on female trees cannot reproduce and any nematodes they carry will also be trapped inside. The biology of the nematodes is diverse, but is poorly understood. Here, we describe the fate of nematodes carried by the pollinating fig wasp Ceratosolen solmsi marchali into Figs on male and female trees of Ficus hispida, in Sumatra, Indonesia. Figs were sampled routinely from both male and female trees over six-month period, some of them were extracted to observe the nematodes development and their population inside. Three species of nematodes developed routinely inside Figs of both sexes: Caenorhabditis sp. (Rhabditidae), Ficophagus cf. centerae and Martininema baculum (Aphelenchoididae). This is the first record of a Caenorhabditis sp. associated with F. hispida. Mean numbers of nematodes reached around 120-140 in both male and female Figs. These peak population sizes coincided with the emergence of the new generation of adult fig wasps in male fig trees. This study showed that Figs from female trees can support nematode development, but the absence of vectors means that the Figs remain lethal traps for any nematodes that develop in them. Just like their fig wasp vectors, the nematodes cannot avoid this routine source of mortality. Keywords: Agaonidae, Caenorhabditis, Aphelenchoididae, Ficus hispida, phoresy, vector
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First record of a non-pollinating fig wasp (Hymenoptera: Sycophaginae) from Dominican amber, with estimation of the size of its host Figs
Journal of Natural History, 2016Co-Authors: Fernando Farache, Jean-yves Rasplus, Dany Azar, Rodrigo A. S. Pereira, Stephen G. ComptonAbstract:Fig trees and their pollinating fig wasps arose about 75 million years ago in the Cretaceous period. Several other groups of chalcid wasps also utilize Figs for larval development, including sycophagines, the putative sister group to pollinating fig wasps. Whereas stone and amber fossil pollinators are known, no fossils representing non-pollinating fig wasp groups have been confirmed previously. Here, we describe the first Sycophaginae from the c. 15-20 Ma Dominican amber, Idarnes thanatos sp. nov. Farache, Rasplus, Pereira and Compton, and discuss its relationships within the Idarnes carme species group. Additionally, we use linear regression to compare body size, ovipositor sheaths length, and host fig size data from extant Idarnes species to estimate the size of its host Figs. Idarnes thanatos was most likely associated with small to medium sized Figs (diameter
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Fig Pollinating Wasp Transfers Nematodes into Figs of Ficus racemosa in Sumatra, Indonesia
2015Co-Authors: Jauharlina Jauharlina, Rina Sriwati, Yusmaini, Natsumi Kanzaki, Stephen G. ComptonAbstract:The fruits (Figs) of fig trees ( Ficus spp, known as ‘bak ara’ in Aceh), are the source of food for many species of faunas in the forest, including birds, monkeys, orangutans, etc. Pollination within the Figs totally depends on female fig wasps that belong to family Agaonidae. Fig trees and their pollinating wasps rely on each other to survive. Female fig wasps are known to transport nematodes into receptive Figs when the wasps enter the Figs to lay eggs. An investigation on the nematodes carried by female pollinating wasps Ceratosolen fusciceps Mayr into Figs of Ficus racemosa was conducted in Sumatra, Indonesia. The Figs on the trees were regularly sampled to determine the presence of nematodes and infer their ecology. The Baermann funnel method was employed to extract the nematodes from the Figs. Eight species of nematodes were recorded from the Figs, two of which are still unidentified. The species found were (1) Teratodiplogaster fignewmani, (2) Teratodiplogaster sp., (3) Parasitodiplogaster sp. , (4) Schistonchus sp1 ., (5) Schistonchus sp2 ., (6) Mononchoides sp., (7) and (8) two undescribed Diplogastridae species (‘umbrella-like’ species 1 and species 2). This is the most diverse fig nematode community recorded. The highest nematode populations were routinely found in D-phase Figs, when the new generations of wasps were about to emerge. Details of the ecology of each nematode species are likely to differ, but as a group they did not seem to significantly affect seed and wasp development in F. racemosa Figs
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Between‐species facilitation by male fig wasps in shared Figs
Ecological Entomology, 2015Co-Authors: Rong Wang, Hui Yu, Rupe J Quinnell, Simon T. Segar, Maximilian Harper, Stephen G. ComptonAbstract:1. Facilitation is recorded from diverse plant–insect interactions, including pollination and herbivory. 2. The significance of facilitation resulting from the behavior of males of multiple fig wasp species inside Figs was investigated. Female fig wasps emerge from natal Figs via exit holes dug by males, especially male pollinators. When no males are present, the females struggle to escape and may die. 3. Ficus microcarpa L. is a widely-established invasive fig tree from Southeast Asia. Its pollinator is absent in South Africa, so the tree cannot reproduce, but two Asian non-pollinating fig wasps (NPFW) Walkerella microcarpae and Odontofroggatia galili occupy its Figs. Abundance patterns of the two NPFW and the proportion of male-free Figs in South Africa, Spain (where the pollinator is introduced), and in China, where the native fig wasp community is diverse, were compared to determine the consequences of reduced species richness for insect survival. 4. Female fig wasps in male-free Figs were found to be trapped, and small clutch sizes contributed to the absence of males in both species. The presence of pollinators in Spain allowed most NPFW to develop in Figs containing males. Far more male-free Figs were present in South Africa, elevating mortality rates among female NPFW. Facilitation of female release by males of other NPFW species nonetheless benefitted the rarer species. 5. Selection pressures in South Africa currently favour greater aggregation of NPFW offspring and/or less female biased sex ratios.
Martine Hossaert-mckey - One of the best experts on this subject based on the ideXlab platform.
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Why do fig wasps actively pollinate monoecious Figs
Oecologia, 2002Co-Authors: Emmanuelle Jousselin, Martine Hossaert-mckey, Edward Allen Herre, Finn KjellbergAbstract:Active pollination, although rare, has been documented in a few pollination mutualisms. Such behaviour can only evolve if it benefits the pollinator in some way. The wasps that pollinate Ficus inflorescences can be active or passive pollinators. They lay their eggs in fig flowers, so that a proportion of flowers will host a wasp larva instead of a seed. We show in an actively pollinated monoecious fig that lack of pollination does not induce fig abortion or affect wasp offspring size but results in smaller numbers of offspring. Hence, conversely to other active pollination systems, seed formation is not obligatory to sustain developing pollinator larvae; however there is a direct fitness cost to active pollinators not to pollinate. We then compared the locations of eggs and fertilised flowers of three actively pollinated Ficus species and one passively pollinated species. We found that more flowers containing wasp eggs were fertilised in the actively pollinated species relative to those of the passively pollinated one. These results along with comparison with similar studies on dioecious Figs, support the hypothesis that active pollination has evolved in fig wasps to ensure that more flowers containing wasp eggs are fertilised as this may increase the chances of successful gall development. The stigmatic platform characterising actively pollinated Figs is probably an adaptation to increase pollen dispersion within the fig.
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Figs and fig pollinators: evolutionary conflicts in a coevoled mutualism.
Trends in ecology & evolution, 1997Co-Authors: Marie-charlotte Anstett, Martine Hossaert-mckey, Finn KjellbergAbstract:Abstract Figs and fig wasps form one of the best known examples of species-specific mutualism and coevolution. Recent experiments and observations have led to a better understanding of the evolutionary processes involved in the origin and maintenance of species interactions. The observed fine-tuned traits involve not only coevolution but also selection acting on only one of the partners. Furthermore, some of the ‘fine-tuned traits' appear to be be preadaptions — traits that existed before the mutalism was establised.
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Volatile compounds from extracts of Figs of Ficus carica
Phytochemistry, 1997Co-Authors: Marc Gibernau, Hans Buser, Jürg Frey, Martine Hossaert-mckeyAbstract:Pentane extracts from Figs of Ficus carica, the common fig tree, were analysed by GC-mass spectroscopy. Four series of extracts were prepared from receptive male Figs, non-receptive male Figs, receptive female Figs and non-receptive female Figs. Extracts from non-receptive Figs are characterised by furanocoumarins (tentatively identified as angelicin and bergapten), sesquiterpene hydrocarbons (i.e. trans-caryophyllene, and a compound tentatively identified as germacrene D), oxygenated sesquiterpenes (i.e. hydroxycaryophyllene) benzyl alcohol and benzylaldehyde. Extracts from receptive Figs of both sexes are characterised by benzyl alcohol, linalool and linalool oxides (furanoid), cinnamic aldehyde, cinnamic alcohol and indole. Extract from female receptive Figs has in addition large amounts of pyranoid (linalool oxides), whereas an extract from male receptive Figs contains eugenol and an unidentified sesquiterpene hydrocarbon. Differences between extracts from male and female Figs appear to be mainly qualitative due to pyranoid compounds, sesquiterpene:~ 1, 2 and 3 for female Figs and eugenol and sesquiterpene 5 for male Figs.
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When Figs Wait for Pollinators: The Length of Fig Receptivity
American Journal of Botany, 1995Co-Authors: Bouchaïb Khadari, Finn Kjellberg, Marc Gibernau, Marie-charlotte Anstett, Martine Hossaert-mckeyAbstract:In plant species with an obligate species-specific pollinator, gamete encounter is a critical phase in the success of reproductive strategies. One of the key factors in the success of gamete encounter, the length of female receptivity, has been rarely studied experimentally. In Ficus species (Moraceae), each exclusively associated with its specific pollinating wasp, the receptive female phase of individual syconia was believed to last only a few days. This estimate, based on field observations of pollinator arrivals, neglected the possibility that unpollinated syconia may remain receptive for a prolonged period. In two distantly related fig species (F. carica and F. aurea), we measured experimentally the duration of receptivity of individual syconia protected from pollinator visits. For these two species, receptivity lasted from 2 to 3 wk. Syconia pollinated at any time during this period of receptivity are capable of setting seeds. Furthermore, it has been assumed that female syconium receptivity stops quickly after pollinator visitation. Our experiments showed that syconia of both species are able to extend their receptive period for a few days longer when visited only by a single wasp. The demonstration of a long duration of female receptivity has important consequences for understanding the maintenance of the fig-wasp mutualism.
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Chemosensory attraction of fig wasps to substances produced by receptive Figs
Entomologia Experimentalis et Applicata, 1994Co-Authors: Martine Hossaert-mckey, Marc Gibernau, Jürg E. FreyAbstract:In the mutualism between Figs (Ficus spp., Moraceae) and their species-specific fig wasp pollinators (Hymenoptera: Agaonidae), location of a receptive host tree by the adult insect is a critical step. The adult female wasp lives only a few days, and must usually fly to a different tree than her natal tree to locate receptive Figs. Trees in receptive phase often occur at very low densities. Reproductive success of both fig and wasp depends on transmission of a very strong signal by the plant. Some evidence exists for the role of olfaction in location of receptive hosts by fig wasps, but very little work has been done on the chemical ecology of host location and host specificity. Here the first experimental evidence is presented for long-distance olfactory attraction of wasps by volatile substances produced by receptive Figs, and for short-distance or contact chemostimulation by host volatiles that elicit entry of the wasp into the fig. In studies using Ficus carica L., pentane extracts of receptive-phase Figs attract the pollinator Blastophaga psenes L. from distances of at least 5 m in the field. Short-distance chemostimulation was demonstrated in laboratory bioassays. Pentane extracts of receptive Figs, when painted onto the ostiole of non-receptive Figs, elicit entry of pollinator wasps. Figs emit volatile compounds attractive to pollinating wasps only during the period of receptivity; pentane extracts of non-receptive Figs are not attractive. A simple reliable procedure is described to compare the attractivity of different types of extracts (total, internal, and external extracts) and of different fractions, in the first step towards identifying attractant substances.
Finn Kjellberg - One of the best experts on this subject based on the ideXlab platform.
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Rush hour at the Museum – Diversification patterns provide new clues for the success of Figs ( Ficus L., Moraceae)
Acta Oecologica, 2018Co-Authors: Sam Bruun-lund, Finn Kjellberg, Brecht Verstraete, Nina RønstedAbstract:Tropical rainforests harbour much of the earth's plant diversity but little is still known about how it evolved and why a small number of plant genera account for the majority. Whether this success is due to rapid turnover or constant evolution for these hyper-diverse plant genera is here tested for the species-rich genus Ficus L. (Figs). The pan-tropical distribution of Figs makes it an ideal study group to investigate rainforest hyper-diversification patterns. Using a recently published, dated and comprehensive phylogenetic hypothesis, we infer that Figs are an old lineage that gradually accumulated species and exhibits very low extinction rates, which corresponds to the 'museum model' of evolution. Overall, no major significant shifts in evolutionary dynamics are detected, yet two shifts with lower probability are found. Hemi-epiphytism, monoecy, and active pollination are traits that possibly are associated with the hyper-diversity found in Figs, making it possible for the plants to occupy new niches followed by extensive radiation over evolutionary time scales. Figs possess unique diversification patterns compared to other typical rainforest genera.
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Diversity of fig glands is associated with nursery mutualism in fig trees
American journal of botany, 2015Co-Authors: Camila De Souza, Finn Kjellberg, Rodrigo Augusto Santinelo Pereira, Cristina Ribeiro Marinho, Simone De Pádua TeixeiraAbstract:Fig trees (Moraceae) have remarkable enclosed inflorescences called Figs or syconia. The flowers are pollinated by host-specific fig wasps that enter the fig to lay their eggs. This nursery pollination system is one of the most studied of tropical mutualism interactions, but the source of the volatiles that attract fig wasps to their specific host Figs has not been confirmed. The fragrance is the basis of host selection and, therefore, of reproductive isolation among sympatric Ficus species. This study locates and characterizes the glands likely to be responsible for pollinator attraction and also protection from herbivory in the Figs of nine Ficus species representing all the major lineages within the genus. Figs with receptive pistillate flowers were examined using light and scanning electron microscopy. Tests for histolocalization of substances were employed to detect glandular activity throughout the Figs. A great diversity of glands is found throughout the fig, and for the first time, the sites producing fragrances are identified. Scent glands are present on the ostiolar bracts and the outer layers of the fig receptacle. Laticifers and phenolic-producing idioblasts, epidermis, and trichomes associated with fig protection occur on the ostiolar bracts, the fig receptacle, and floral tissues. The volatiles produced by glands on the ostiolar bracts are candidate sources for the long-distance attraction of pollinator fig wasps. Scent glands on the outer layers of the receptacle may also play a role in chemical perception of the Figs or may be related to their protection. The high cost to the plants if the Figs are eaten and the temperature conditions required for nursery pollination are likely the factors that led to the selection of phenolic glands and laticifers during the group's evolution. © 2015 Botanical Society of America.
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Why do fig wasps actively pollinate monoecious Figs
Oecologia, 2002Co-Authors: Emmanuelle Jousselin, Martine Hossaert-mckey, Edward Allen Herre, Finn KjellbergAbstract:Active pollination, although rare, has been documented in a few pollination mutualisms. Such behaviour can only evolve if it benefits the pollinator in some way. The wasps that pollinate Ficus inflorescences can be active or passive pollinators. They lay their eggs in fig flowers, so that a proportion of flowers will host a wasp larva instead of a seed. We show in an actively pollinated monoecious fig that lack of pollination does not induce fig abortion or affect wasp offspring size but results in smaller numbers of offspring. Hence, conversely to other active pollination systems, seed formation is not obligatory to sustain developing pollinator larvae; however there is a direct fitness cost to active pollinators not to pollinate. We then compared the locations of eggs and fertilised flowers of three actively pollinated Ficus species and one passively pollinated species. We found that more flowers containing wasp eggs were fertilised in the actively pollinated species relative to those of the passively pollinated one. These results along with comparison with similar studies on dioecious Figs, support the hypothesis that active pollination has evolved in fig wasps to ensure that more flowers containing wasp eggs are fertilised as this may increase the chances of successful gall development. The stigmatic platform characterising actively pollinated Figs is probably an adaptation to increase pollen dispersion within the fig.
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Shift to mutualism in parasitic lineages of the fig/fig wasp interaction
Oikos, 2001Co-Authors: Emmanuelle Jousselin, Jean-yves Rasplus, Finn KjellbergAbstract:The interaction between Ficus and their pollinating wasps (Chalcidoidea, Agaonidae) represents a striking example of mutualism. Figs also host numerous non-pollinating wasps belonging to other chalcidoid families. We show that six species of Ficus that are passively pollinated by the agaonid genus Waterstoniella also host specific wasps belonging to the chalcidoid genera Diaziella (Sycoecinae) and Lipothymus (Otitesellinae). Both belong to lineages that are considered as parasites of the fig/fig wasp mutualism. We show that these wasps are efficient pollinators of their hosts. Pollen counts on wasps of a species of Diaziella hosted by Ficus paracamptophylla show that Diaziella sp. transports more pollen than the associated pollinator when emerging from its natal fig. Further, the number of pollinated flowers in receptive Figs is best explained by the number of Diaziella plus the number of Waterstoniella that had entered it. Figs that were colonised by Diaziella always produced seeds: Diaziella does not overexploit its host. Similarly, Figs of Ficus consociata that were colonised solely by a species of Lipothymus produced as many seeds as Figs that were colonised only by the legitimate pollinator Waterstoniella malayana. Diaziella sp. and Lipothymus sp. seem to pollinate their host fig as efficiently as do the associated agaonid wasps. Previous studies, on actively pollinated Ficus species, have found that internally ovipositing non-agaonid wasps are parasites of such Ficus species. Hence, mode of pollination of the legitimate pollinator conditions the outcome of the interaction between internally ovipositing parasites and their host.
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Figs and fig pollinators: evolutionary conflicts in a coevoled mutualism.
Trends in ecology & evolution, 1997Co-Authors: Marie-charlotte Anstett, Martine Hossaert-mckey, Finn KjellbergAbstract:Abstract Figs and fig wasps form one of the best known examples of species-specific mutualism and coevolution. Recent experiments and observations have led to a better understanding of the evolutionary processes involved in the origin and maintenance of species interactions. The observed fine-tuned traits involve not only coevolution but also selection acting on only one of the partners. Furthermore, some of the ‘fine-tuned traits' appear to be be preadaptions — traits that existed before the mutalism was establised.
Yan-qiong Peng - One of the best experts on this subject based on the ideXlab platform.
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Larger Fig Wasps Are More Careful About Which Figs to Enter - With Good Reason
PloS one, 2013Co-Authors: Cong Liu, Da-rong Yang, Stephen G. Compton, Yan-qiong PengAbstract:Floral longevity reflects a balance between gains in pollinator visitation and the costs of flower maintenance. Because rewards to pollinators change over time, older flowers may be less attractive, reducing the value of extended longevity. Un-pollinated Figs, the inflorescences of Ficus species , can remain receptive for long periods, but Figs that are older when entered by their host-specific fig wasp pollinators produce fewer seeds and fig wasp offspring. Our field experiments with Ficus hispida , a dioecious fig tree, examined how the length of time that receptive Figs have remained un-pollinated influences the behaviour and reproductive success of its short-lived fig wasp pollinator, Ceratosolen solmsi marchali. The results were consistent in three different seasons, and on male and female trees, although receptivity was greatly extended during colder months. Pollinators took longer to find the ostioles of older Figs, and longer to penetrate them. They also became increasingly unwilling to enter Figs as they aged, and increasing numbers of the wasps became trapped in the ostiolar bracts. Larger individuals were particularly unwilling to enter older Figs, resulting in older Figs being pollinated by smaller wasps. On female trees, where Figs produce only seeds, seed production declined rapidly with fig age. On male trees, the numbers and size of fig wasp offspring declined, and a higher proportion were male. Older male Figs are harder to enter, especially for larger individuals, and offer poorer quality oviposition opportunities. This study opens an interesting new perspective on the coevolution of Figs and their pollinators, especially factors influencing pollinator body size and emphasises the subtleties of interactions between mutualists.
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‘Push’ and ‘pull’ responses by fig wasps to volatiles released by their host Figs
Chemoecology, 2012Co-Authors: Ding Gu, Yan-qiong Peng, Stephen G. Compton, Da-rong YangAbstract:In the specific mutualism between fig trees (Ficus) and their obligate pollinating fig wasps (Agaonidae), it is crucial that fig wasps can recognize the developmental stages of their host Figs. However, the responses of fig wasps to volatiles released from Figs during their developmental phases are less clearly understood and are the focus of this study. We extracted and identified the volatiles released from the Figs of Ficus curtipes throughout their development. Using Y-tube choice experiments, we also compared the behavioural responses of the tree’s pollinator (Eupristina sp.) to Figs at different developmental stages, and compared these results to those obtained by trapping fig wasps as they arrived at a tree with a developing fig crop. The chemical composition of the fig volatiles changed during fig development with the blends exhibiting clear segregation among Figs at different developmental phases. Male phase Figs had the most distinct blend. Fig wasp females were preferentially attracted to receptive Figs, but Figs at most other developmental phases were also attractive. Conversely, male phase Figs had a repellent effect. These results were supported by the behaviour of the wasps under natural conditions, with small numbers of fig wasps arriving at the tree before and after receptive Figs were present. These results indicate a more complex relationship between fig volatiles and fig wasp behaviour than previously realized, with volatiles mediating both the initial meeting of the mutualists to achieve pollination and egg laying and the subsequent departure of the next generation of fig wasps. This offers an explanation for the specialization and long-term coexistence of Figs and fig wasps.
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Exchange of hosts: can agaonid fig wasps reproduce successfully in the Figs of non-host Ficus?
Die Naturwissenschaften, 2012Co-Authors: Pei Yang, Yan-qiong Peng, Da-rong YangAbstract:In the obligate mutualism between Figs (Ficus) and their specific pollinators (Chalcidoidea, Agaonidae), each species of fig wasp typically reproduces in Figs of a single host species. Host specificity is maintained largely because pollinators are attracted to tree-specific volatiles released from their host Figs, but whether the wasps can reproduce if they enter Figs of non-host species is unclear. We investigated the reproductive success of Ceratosolen emarginatus (associated with Ficus auriculata) and Ceratosolen sp. (associated with F. hainanensis) in atypical hosts by experimentally introducing foundresses into host and non-host Figs. F. auriculata Figs entered by Ceratosolen sp. were more likely to abort than if entered by C. emarginatus, but abortion of F. hainanensis Figs was not affected by pollinator species. Single C. emarginatus foundresses produced more but smaller offspring in F. hainanensis than in their normal host. Conversely Ceratosolen sp. produced fewer but larger offspring in F. auriculata than in their normal host, probably as a result of having longer to develop. Mean style length differences, relative to the lengths of the wasps’ ovipositors, may have dictated the number of offspring produced, with oviposition made easier by the shorter styles in F. hainanensis Figs. Our results imply that, in addition to morphological constraints and tree-specific volatiles, reduced reproductive success in atypical hosts can be another factor maintaining host specificity, but for other species only behavioural changes are required for host switching to occur.
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Ecology of parasite Sycophilomorpha sp. on Ficus altissima and its effect on the fig-fig wasp mutualism.
Parasitology, 2010Co-Authors: Yan-qiong Peng, J. B. Zhao, Rhett D Harrison, D. R. YangAbstract:Figs and their pollinating wasps are a classic example of an obligate mutualism. In addition, Figs are parasitized by a suite of non-mutualistic wasps whose basic ecology is largely undescribed. Sycophilomorpha (subfamily Epichrysomallinae) fig wasps are ovule gallers and the genus contains only 1 described species. An undescribedSycophilomorpha species parasitized Ficus altissima at Xishuangbana, Southwestern China. The wasp was observed ovipositing on the tiny immature Figs that were still concealed beneath the involucral bracts. A Sycophilomorpha wasp oviposited on more than 1 fig and spent long time-periods to lay large clutches on a single fig. The wasps naturally occurred on all 7 sampled trees, but the occurrence of wasps was significantly different among trees, crops and months. These wasps were able to prevent unpollinated Figs from being aborted, and their offspring were able to develop in the Figs that otherwise had no pollinator wasps or seeds. The Sycophilomorpha wasp had a detrimental effect on the fig–fig wasp mutualism. Figs in which Sycophilomorpha wasps were present, produced significantly fewer seeds, pollinators and cheaters. However, the abundance of Sycophilomorpha in a fig was only significantly negatively correlated with pollinator production and not seed or cheater production. Our study illustrates a previously unknown fig wasp niche and expands our understanding of factors that can affect the fig–fig wasp interaction.
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A species of fig tree and three unrelated fig wasp pollinators
Evolutionary Ecology Research, 2008Co-Authors: Feng-ping Zhang, Yan-qiong Peng, Jun-ming Guan, Da-rong YangAbstract:Background and question: A few non-agaonid wasps can enter Figs to oviposit and effectively pollinate their fig hosts. In Xishuangbanna (Yunnan, SW China), Ficus curtipes is passively pollinated by an undescribed Eupristina species (Agaonidae). Two species of non-agaonid fig wasps, Diaziella yangi and Lipothymus sp., also enter the fig to oviposit. Yet such wasps do not establish a mutualistic relationship with Figs similar to that of agaonids. Why? Method: Using controlled experiments in which only one foundress per species was introduced to a fig, we compared the effect of the three wasp species on pollination. We recorded foundress distribution in the fig female floral phase, and counted the number of wasps and seeds in the male floral phase. Results: Diaziella yangi and Lipothymus sp. follow Eupristina sp. into the Figs, and both non-agaonids are efficient pollinators. In nature, most Figs were entered by just one species of foundress: 36% were entered by Eupristina sp. only, 8% by D. yangi only, and 3% by Lipothymus sp. only. About 28% of adult fig wasps emerging from Figs were D. yangi, 4% were Lipothymus sp., and 65% were Eupristina sp.; ten other non-agaonids ovipositing from outside the fig comprised just 3% of the adult wasps that emerged from Figs. Both species of fig-entering non-agaonid wasps significantly reduced the number of Eupristina sp. emerging from mature Figs but had no effect on seed production. If D. yangi or Lipothymus sp. was introduced to Figs containing one foundress of Eupristina sp., both non-agaonid wasps produced offspring. But without the Eupristina, D. yangi and Lipothymus sp. failed to reproduce. Diaziella yangi and Lipothymus sp. depend on the agaonid, Eupristina, to make galls. Conclusion: Because they depend on the legitimate pollinator to make galls, neither D. yangi nor Lipothymus sp. is able to replace the agaonid wasp and establish a mutualistic relationship with their host fig.
Da-rong Yang - One of the best experts on this subject based on the ideXlab platform.
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Larger Fig Wasps Are More Careful About Which Figs to Enter - With Good Reason
PloS one, 2013Co-Authors: Cong Liu, Da-rong Yang, Stephen G. Compton, Yan-qiong PengAbstract:Floral longevity reflects a balance between gains in pollinator visitation and the costs of flower maintenance. Because rewards to pollinators change over time, older flowers may be less attractive, reducing the value of extended longevity. Un-pollinated Figs, the inflorescences of Ficus species , can remain receptive for long periods, but Figs that are older when entered by their host-specific fig wasp pollinators produce fewer seeds and fig wasp offspring. Our field experiments with Ficus hispida , a dioecious fig tree, examined how the length of time that receptive Figs have remained un-pollinated influences the behaviour and reproductive success of its short-lived fig wasp pollinator, Ceratosolen solmsi marchali. The results were consistent in three different seasons, and on male and female trees, although receptivity was greatly extended during colder months. Pollinators took longer to find the ostioles of older Figs, and longer to penetrate them. They also became increasingly unwilling to enter Figs as they aged, and increasing numbers of the wasps became trapped in the ostiolar bracts. Larger individuals were particularly unwilling to enter older Figs, resulting in older Figs being pollinated by smaller wasps. On female trees, where Figs produce only seeds, seed production declined rapidly with fig age. On male trees, the numbers and size of fig wasp offspring declined, and a higher proportion were male. Older male Figs are harder to enter, especially for larger individuals, and offer poorer quality oviposition opportunities. This study opens an interesting new perspective on the coevolution of Figs and their pollinators, especially factors influencing pollinator body size and emphasises the subtleties of interactions between mutualists.
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‘Push’ and ‘pull’ responses by fig wasps to volatiles released by their host Figs
Chemoecology, 2012Co-Authors: Ding Gu, Yan-qiong Peng, Stephen G. Compton, Da-rong YangAbstract:In the specific mutualism between fig trees (Ficus) and their obligate pollinating fig wasps (Agaonidae), it is crucial that fig wasps can recognize the developmental stages of their host Figs. However, the responses of fig wasps to volatiles released from Figs during their developmental phases are less clearly understood and are the focus of this study. We extracted and identified the volatiles released from the Figs of Ficus curtipes throughout their development. Using Y-tube choice experiments, we also compared the behavioural responses of the tree’s pollinator (Eupristina sp.) to Figs at different developmental stages, and compared these results to those obtained by trapping fig wasps as they arrived at a tree with a developing fig crop. The chemical composition of the fig volatiles changed during fig development with the blends exhibiting clear segregation among Figs at different developmental phases. Male phase Figs had the most distinct blend. Fig wasp females were preferentially attracted to receptive Figs, but Figs at most other developmental phases were also attractive. Conversely, male phase Figs had a repellent effect. These results were supported by the behaviour of the wasps under natural conditions, with small numbers of fig wasps arriving at the tree before and after receptive Figs were present. These results indicate a more complex relationship between fig volatiles and fig wasp behaviour than previously realized, with volatiles mediating both the initial meeting of the mutualists to achieve pollination and egg laying and the subsequent departure of the next generation of fig wasps. This offers an explanation for the specialization and long-term coexistence of Figs and fig wasps.
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Exchange of hosts: can agaonid fig wasps reproduce successfully in the Figs of non-host Ficus?
Die Naturwissenschaften, 2012Co-Authors: Pei Yang, Yan-qiong Peng, Da-rong YangAbstract:In the obligate mutualism between Figs (Ficus) and their specific pollinators (Chalcidoidea, Agaonidae), each species of fig wasp typically reproduces in Figs of a single host species. Host specificity is maintained largely because pollinators are attracted to tree-specific volatiles released from their host Figs, but whether the wasps can reproduce if they enter Figs of non-host species is unclear. We investigated the reproductive success of Ceratosolen emarginatus (associated with Ficus auriculata) and Ceratosolen sp. (associated with F. hainanensis) in atypical hosts by experimentally introducing foundresses into host and non-host Figs. F. auriculata Figs entered by Ceratosolen sp. were more likely to abort than if entered by C. emarginatus, but abortion of F. hainanensis Figs was not affected by pollinator species. Single C. emarginatus foundresses produced more but smaller offspring in F. hainanensis than in their normal host. Conversely Ceratosolen sp. produced fewer but larger offspring in F. auriculata than in their normal host, probably as a result of having longer to develop. Mean style length differences, relative to the lengths of the wasps’ ovipositors, may have dictated the number of offspring produced, with oviposition made easier by the shorter styles in F. hainanensis Figs. Our results imply that, in addition to morphological constraints and tree-specific volatiles, reduced reproductive success in atypical hosts can be another factor maintaining host specificity, but for other species only behavioural changes are required for host switching to occur.
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A species of fig tree and three unrelated fig wasp pollinators
Evolutionary Ecology Research, 2008Co-Authors: Feng-ping Zhang, Yan-qiong Peng, Jun-ming Guan, Da-rong YangAbstract:Background and question: A few non-agaonid wasps can enter Figs to oviposit and effectively pollinate their fig hosts. In Xishuangbanna (Yunnan, SW China), Ficus curtipes is passively pollinated by an undescribed Eupristina species (Agaonidae). Two species of non-agaonid fig wasps, Diaziella yangi and Lipothymus sp., also enter the fig to oviposit. Yet such wasps do not establish a mutualistic relationship with Figs similar to that of agaonids. Why? Method: Using controlled experiments in which only one foundress per species was introduced to a fig, we compared the effect of the three wasp species on pollination. We recorded foundress distribution in the fig female floral phase, and counted the number of wasps and seeds in the male floral phase. Results: Diaziella yangi and Lipothymus sp. follow Eupristina sp. into the Figs, and both non-agaonids are efficient pollinators. In nature, most Figs were entered by just one species of foundress: 36% were entered by Eupristina sp. only, 8% by D. yangi only, and 3% by Lipothymus sp. only. About 28% of adult fig wasps emerging from Figs were D. yangi, 4% were Lipothymus sp., and 65% were Eupristina sp.; ten other non-agaonids ovipositing from outside the fig comprised just 3% of the adult wasps that emerged from Figs. Both species of fig-entering non-agaonid wasps significantly reduced the number of Eupristina sp. emerging from mature Figs but had no effect on seed production. If D. yangi or Lipothymus sp. was introduced to Figs containing one foundress of Eupristina sp., both non-agaonid wasps produced offspring. But without the Eupristina, D. yangi and Lipothymus sp. failed to reproduce. Diaziella yangi and Lipothymus sp. depend on the agaonid, Eupristina, to make galls. Conclusion: Because they depend on the legitimate pollinator to make galls, neither D. yangi nor Lipothymus sp. is able to replace the agaonid wasp and establish a mutualistic relationship with their host fig.
