Figs (Moracea: Ficus) and fig wasps (Hymenoptera: Chlocloids: Agaonideae) depend on each other to complete their reproduction. Monoecious fig species and their pollinating wasps are in conflict over the use of fig ov...Figs (Moracea: Ficus) and fig wasps (Hymenoptera: Chlocloids: Agaonideae) depend on each other to complete their reproduction. Monoecious fig species and their pollinating wasps are in conflict over the use of fig ovaries which can either produce one seed or one wasp. From observation on Ficus virens Ait., we showed that female flowers with outer layer of ovaries (near to the wall of syconium) had no significant difference from that with inner and interval layer of ovaries (near to the syconium cavity), in which most seeds and wasps were produced. This meant that fig tree provided the same potential resource for seed and wasps production. Observation indicated that there was usually only one foundress in syconium at female flower phase and no com- petition pollinators. Measurement of the style length of female flowers and the ovipositor of pollinators indicated that most ovaries could be reached by pollinator’s ovipositor. However, at the male flower phase, production of seeds was significantly more than that of wasps including non-pollinating wasps but there was no significant difference between seed and pollinating wasp production when without non-pollinating wasps produced. This result indicated that non-pollinating wasps competed ovaries not with seeds but with pollinating wasps for ovipositing. Bagged experiment showed that the sampling fig species was not self-sterile which was important for figs and wasps to survive bad season. Seed production in self-pollinated figs was not significantly different from total wasps in- cluding non-pollinating ones. This might be related with the weaker competition among wasps since bagged figs were not easy to reach by wasps from outside.展开更多
Hybridization plays a significant role in biological evolution. However, it is not clear whether ecological contingency differentially influences likelihood of hybridization, particularly at ecological margins where p...Hybridization plays a significant role in biological evolution. However, it is not clear whether ecological contingency differentially influences likelihood of hybridization, particularly at ecological margins where parental species may exhibit reduced fitnesses. Moreover, it is unknown whether future ecosystem change will increase the prevalence of hybridization. Ficus heterostyla and F. squamosa are closely related species co-distributed from southern Thailand to southwest China where hybridization, yielding viable seeds, has been documented. As a robust test of ecological factors driving hybridization, we investigated spatial hybridization signatures based on nuclear microsatellites from extensive population sampling across a widespread contact range. Both species showed high population differentiation and strong patterns of isolation by distance. Admixture estimates exposed asymmetric interspecific gene flow.Signatures of hybridization increase significantly towards higher latitude zones, peaking at the northern climatic margins. Geographic variation in reproductive phenology combined with ecologically challenging marginal habitats may promote this phenomenon. Our work is a first systematic evaluation of such patterns in a comprehensive, latitudinally-based clinal context, and indicates that tendency to hybridize appears strongly influenced by environmental conditions. Moreover, that future climate change scenarios will likely alter and possibly augment cases of hybridization at ecosystem scales.展开更多
Fig trees are important components of tropical forests, because their fruits are eaten by so many vertebrates, but they depend on pollinating fig wasps to produce mature fruits. Disturbance to habitat structure can ha...Fig trees are important components of tropical forests, because their fruits are eaten by so many vertebrates, but they depend on pollinating fig wasps to produce mature fruits. Disturbance to habitat structure can have a major impact on insect diversity and com- position, potentially reducing fruit yields. We investigated the impact of habitat disturbance on the fig wasp community associated with male figs ofFicus tinctoria in Xishuangbanna, China. The community comprised one pollinator species Liporrhopalum gibbosae and six non-pollinating wasp species： Sycoscapter sp. 1, Philotrypesis ravii, Philotrypesis sp. 1, Neosycophila omeomorpha, Sycophila sp.1, and Walkerella sp.1. More disturbed areas were characterized by higher temperatures, less shade, and more vehicle noise. The response of the fig wasp community was complex, with no simple relationship between intensity of disturbance and pollinator abundance. However, the sex ratios （proportion of male progeny） of pollinators increased significantly in more disturbed areas. We conclude that potential changes in fig wasp community composition brought about by disturbance, are unpredictable, with unclear consequences for tropical rainforest biodiversity.展开更多
基金Supported by the Knowledge Innovation Research Program,Chinese Academy of Sciences (KSCX2-SW-105)
文摘Figs (Moracea: Ficus) and fig wasps (Hymenoptera: Chlocloids: Agaonideae) depend on each other to complete their reproduction. Monoecious fig species and their pollinating wasps are in conflict over the use of fig ovaries which can either produce one seed or one wasp. From observation on Ficus virens Ait., we showed that female flowers with outer layer of ovaries (near to the wall of syconium) had no significant difference from that with inner and interval layer of ovaries (near to the syconium cavity), in which most seeds and wasps were produced. This meant that fig tree provided the same potential resource for seed and wasps production. Observation indicated that there was usually only one foundress in syconium at female flower phase and no com- petition pollinators. Measurement of the style length of female flowers and the ovipositor of pollinators indicated that most ovaries could be reached by pollinator’s ovipositor. However, at the male flower phase, production of seeds was significantly more than that of wasps including non-pollinating wasps but there was no significant difference between seed and pollinating wasp production when without non-pollinating wasps produced. This result indicated that non-pollinating wasps competed ovaries not with seeds but with pollinating wasps for ovipositing. Bagged experiment showed that the sampling fig species was not self-sterile which was important for figs and wasps to survive bad season. Seed production in self-pollinated figs was not significantly different from total wasps in- cluding non-pollinating ones. This might be related with the weaker competition among wasps since bagged figs were not easy to reach by wasps from outside.
基金supported by the National Natural Science Foundation of China (3180031332261123001)+1 种基金Applied Basic Research Foundation of Yunnan Province (202301AT070378, 2019FB034)the “Light of West China” Program of the Chinese Academic of Sciences to J.-F.Huang。
文摘Hybridization plays a significant role in biological evolution. However, it is not clear whether ecological contingency differentially influences likelihood of hybridization, particularly at ecological margins where parental species may exhibit reduced fitnesses. Moreover, it is unknown whether future ecosystem change will increase the prevalence of hybridization. Ficus heterostyla and F. squamosa are closely related species co-distributed from southern Thailand to southwest China where hybridization, yielding viable seeds, has been documented. As a robust test of ecological factors driving hybridization, we investigated spatial hybridization signatures based on nuclear microsatellites from extensive population sampling across a widespread contact range. Both species showed high population differentiation and strong patterns of isolation by distance. Admixture estimates exposed asymmetric interspecific gene flow.Signatures of hybridization increase significantly towards higher latitude zones, peaking at the northern climatic margins. Geographic variation in reproductive phenology combined with ecologically challenging marginal habitats may promote this phenomenon. Our work is a first systematic evaluation of such patterns in a comprehensive, latitudinally-based clinal context, and indicates that tendency to hybridize appears strongly influenced by environmental conditions. Moreover, that future climate change scenarios will likely alter and possibly augment cases of hybridization at ecosystem scales.
基金Acknowledgments The authors would like to thank Professor Jean-Yves Rusplus for identifying the fig wasps of Ficus tinctoria. We wish to thank Stephen Compton for providing help with statistical methods and revising the manuscript. We also thank Iain Taylor, Paolo Pelosi, Roy Turkington, Loren Bell and Kari Malen and anonymous referees for good suggestions and reviewing the manuscript. The authors also thank Zhen-Ji Wang, Jun-Ming Guan, Pei Yang and Yi Zhao for their help with the fieldwork. The study was funded by the Chinese Natural Science Foundation （30571507, 30670358）.
文摘Fig trees are important components of tropical forests, because their fruits are eaten by so many vertebrates, but they depend on pollinating fig wasps to produce mature fruits. Disturbance to habitat structure can have a major impact on insect diversity and com- position, potentially reducing fruit yields. We investigated the impact of habitat disturbance on the fig wasp community associated with male figs ofFicus tinctoria in Xishuangbanna, China. The community comprised one pollinator species Liporrhopalum gibbosae and six non-pollinating wasp species： Sycoscapter sp. 1, Philotrypesis ravii, Philotrypesis sp. 1, Neosycophila omeomorpha, Sycophila sp.1, and Walkerella sp.1. More disturbed areas were characterized by higher temperatures, less shade, and more vehicle noise. The response of the fig wasp community was complex, with no simple relationship between intensity of disturbance and pollinator abundance. However, the sex ratios （proportion of male progeny） of pollinators increased significantly in more disturbed areas. We conclude that potential changes in fig wasp community composition brought about by disturbance, are unpredictable, with unclear consequences for tropical rainforest biodiversity.
