Ficus pumila L.var.pumila (FPP) and F.pumila L.var.awkeotsang (Makino) Corner (FPA) are evergreen climbing dioecious fig plants,the relationship that between two kinds of fig trees is the original variant and variant.FPP and FPA are respectively pollinated by their own obligated pollinator,and the relationship between two pollinating wasps is determined by the cryptic species.FPP and FPA built obligate symbiotic relationships with their specific pollinating wasps.Figs volatiles play an important role in the maintenance of pollinating wasps and their host symbiotic relationship.Pollinating wasps can follow the volatiles of specific host female phase figs,and enter figs for oviposition and pollination.In this study,we used a Y-tube olfactometer to test the behavioral responses of Wiebesia pumilae (Hill) Wiebes,the pollinating wasps of FPP and FPA,to the female phase fig volatiles of FPP and FPA.The results showed that:(1) the size of female phase figs had no significant effect on the behavioral responses of W.pumilae;both female and male receptive phases of large and small type figs of FFP volatiles had a strong attractiveness to its obligate pollinator;(2) the concentration of fig volatiles had a significant effect on W.pumilae behavior,both female and male receptive phase figs of FPA and FPP volatiles had a threshold response phenomenon on their obligate pollinators;when the volatile concentrations did not exceed the threshold value with the increase in volatile concentration,the attraction of pollinators increased;however,if the volatile concentration exceeded the threshold value,the attraction of pollinators decreased;(3) the pollinating wasps of FPP to both female and male low concentration female phase fig volatiles of FPA and pollinating wasps of FPA to both male and female low concentration female phase figs volatiles of FPP were neither attracted nor deterred.The pollinating wasps of FPA showed significant preference for both male and female high concentration female phase fig volatiles of FPP,whereas the pollinator of FPP was deterred by both male and female high concentration phase figs volatiles of FPA.Therefore,the pollinating wasps of FPA and FPP showed asymmetric host specificity.It is possible that the pollinating wasps of FPA enter female and male phase figs of FPP for pollination and oviposition,respectively;however,in Fuzhou,it is difficult for the pollinating wasps of FPP to enter the female and male phase figs of FPA for pollination and oviposition,respectively.Our results will provide the scientific basis for the studies on chemical signaling mechanisms of fig-wasp mutualism and FPA cultivation.

高榕,雌雄同株,与其共生的形态高度相似的传粉小蜂Eupristina altissima与非传粉小蜂Eupristina sp.均为果内产卵。利用Y型嗅觉仪生物测定法研究E.altissima和Eupristina sp.对不同发育期高榕榕果挥发物以及合成信息素混合物的行为反应差异。结果表明:E.altissima和Eupristina sp.对高榕雌花期榕果挥发物具极显著趋向行为,对高榕雄花期榕果挥发物具极显著驱避行为,表明E.altissima与Eupristina sp.雌蜂能够敏锐辨别高榕雌花期和雄花期榕果的挥发物,快速远离雄花期榕果,并实现对宿主雌花期榕果的定位。但是,E.altissima与Eupristina sp.对其它发育时期榕果挥发物的行为反应具有差异性,前者对雌前期榕果和传粉或产卵后榕果释放的挥发物存在显著的趋避反应,而后者无明显的行为偏向性,表明E.altissima能够识别雌前期榕果和传粉或产卵后榕果,可避免误入其中而无法繁殖后代,Eupristina sp.则不具备这种识别能力。E.altissima和Eupristina sp.小蜂对合成信息素的行为反应也高度相似,表现为芳樟醇、苯乙烯,以及苯乙烯和金合欢醇的交互作用对两种小蜂选择行为影响显著,组合A 1 B 2 C 2 （0.5%Linalool+1%Benzyl ethylene+1%Farnesol）的混合信息素对两种小蜂具有极显著的驱避作用,而组合A 2 B 1 C 1 （1%Linalool+0.5%Benzyl ethylene+0.5%Farnesol）,A 2 B 1 C 2 （1%Linalool+0.5%Benzyl ethylene+1%Farnesol）,A2B2C1（1%Linalool+1%Benzyl ethylene+0.5%Farnesol）的混合信息素对其具有极显著的吸引作用,但两种小蜂对组合A 1 B 1 C 1 （0.5%Linalool+0.5%Benzyl ethylene+0.5%Farnesol）的行为反应存在差异。两种小蜂对榕果挥发物和合成信息素的反应异同,可能与其触角结构的差异密切相关。研究结果为探究榕-蜂共生体系的化学信号传导机制提供科学依据。