Wasp Community Structure Inside Syconia Of Ficus Benjamina L. And Effect Of Gall Midge On Fig-Fig Wasp Symbiotic System

Ficus benjamina (monoecious) is a popular cultivated tree for ornamental purpose worldwide, but the fig wasp community inside the syconium of the specie and the community structure at different position and directions of the tree crown is still poorly known. Samples from three trees in Xishuangbanna, Yunnan show that fig wasps inside the syconia consisted of 13 species belonging to 8 genera of Chaleidoidae. Eupristina koningsbergeri is pollinator, the others are non-pollinators.Speices diversity indexes and eveness indexes of fig wasps in the syconia in different directions show no significant difference. Unlike pollinator, non-pollinators oviposit from the outside and can be easily to be interrupted by disturbance, some weak-adaption non-pollinating fig wasps are cline to oviposit in the syconia at the higher position of the tree crown. Therefore, species diversity indexes at top and middle of the tree were sighnifcantly higher than at the bottom.The number of pollinators and non-pollinators in the syconia of different positions and directions have no significant difference. It shows that non-pollinators make full use of the resources of host in order to ease resource competition in pollinators, nonpollinators and between pollinators and non-pollinators. It is beneficial to stabilize fig-fig wasp mutualism. There is no significant correlationship between non-pollinators and pollinator on three trees, but for one tree non-pollinators have reduced the number of seeds, that is ,the tree female function.An unidentified gall midge, belonging to an undescribed genus and species near Horidiplosis (Diptera: Cecidomyiidae) is recorded for the first time inhabiting the figs of Ficus benjamina. The larvae of gall midge develop inside galled ovules and have occpied present in over 86% of the figs, with average individual density about 68 galls per fig. Because the spatial and resources limitation, gall midge inside syconia has a major negative impact on both partners in the fig–fig wasp mutualism. Under the same pressure of gall midge, the fig–fig pollinator mutualism shows selfish, and preferrs to locate more resources to its seeds reproduction, which caused the fig wasp suffered more damage by the gall midge. Figs containing gall midge produce fewer seeds and contains almost no fig wasps compared to figs without gall midge.