The Morphological Adaptation And Character Evolution Of Fig Wasps In China

The interaction between figs and their pollinating fig wasps represents a unity of mutualism and parasitism and becomes a model system for studying origin and evolution of mutualism, resources conflicts, equilibrium mechanisms of mutualism, sex allocation and precise adaptation.Figs provide the special and unusual environment for the fig wasps. In such a dark, wet, and closed environment, many species coexist and conflict each other, in a system view, and reaching at equilibrium after several millions of years'evolution. The fig wasps evolved the precise adaptive morphological characters under the natural pressure, such as the shape of head, the antennal groove, the spiracle, the ovipositor, and so on. But there is no evidence of adaptation in the morphology of the antennal sensilla, even this character is most important in reflecting the pressure and the adaption to the fig because it is the unit of communication systems. Thus, the aim of this study was to investigate the morphology of the antennal sensilla of the fig wasps including 23 species and 54 forms from 15 fig species.Our result shows that there is the extremely dimorphism in the morphology of the antennal sensilla in the fig wasps. Because the sexes are under the different ecological pressure and functions, they have evolved the different adapted morphology. And the antennal sensilla on the scape, the pedical and the third segment of the pollinating females are very special because the females lose their most of the antenna when they squeeze through the ostiole of the figs to pollinate and oviposit. Also the different life history and the different function of pollinating make the morphology of the antennal sensilla of the non-pollinating fig wasps different. Besides, the morphology of the antennal sensilla of the pollinating males and the non-pollinating males which do not have polymorphism is much degenerated. And the fact that the morphology of the antennal sensilla between the winged male and the wingless male of the same species of some non-pollinating species is not significant different suggests the winged male is not far from their natal tree to find the female. The different morphology of the antennal sensilla of the different male morph of the same species indicates the adaptation to the different mate strategies.The analysis on the character evolution implies that there exists the independent evolution many times in the history of pollinating fig wasps. The complicated character and the complex evolution history reflect how the pressure acts on the morphology of the fig wasps very well.This study provides new angle from witch to study the morphology evolution and the character phylogeny of fig wasps and helps to comprehend the behavior strategies and the ecological relationship among fig wasps.