Research On Characteristics Of Pollination And Oviposition In Fig-Fig Wasp Mutualism

Ficus trees relies on their obligate pollinating wasps for pollination and provides the breeding resource and place for the pollinator,which forms the most classic coevolutionary relationship between plants and animals.In the receptive phase of figs,the wasps need to complete pollination and oviposition within the limited survival time,but how does the pollinator distribute the survival time and balance between the mission of pollination and oviposition remained an unsettled question.In this study,four Ficus species belonging to subgenus Sycormous and their specific pollinators were selected as the research materials.By observing the morphological structure and behavior characteristics of figs and their pollinators,and show the behaviour video of pollinators in the figs,combined with the controlled pollinator introducing experiment,the time distribution of pollination and oviposition of pollinators and the resulting fig-fig wasp reproduction differences were studied.The main results are as follows:1.The style lengths of female flowers were varied among different Ficus trees,and there was a certain matching relationship between the ovipositor length of the wasps and the style length of female flowes,the pollinating fig wasp had the potential ability to oviposit in more female flowers.Moreover,the morphological character of stigma of female flowers were adaptive evolution for the characters of oviposition and pollination of fig wasps.2.The four species of pollinating fig wasps had developed pollination structures and actively pollinating behavior for their Ficus hosts,but the characters of pollination and oviposition behaviors of pollinators were quite different between monoecious and dioecious figs,and also did the behaviors of pollinators in male figs and female figs in dioecious figs.In the monoecious figs(Ficus racemosa),the pollination and oviposition behaviors of pollinator were separated obviously,which pollinator first focused on oviposition and then pollinated female flowers,this pattern guaranteed the reproductive success of both fig and pollinator as much as possible.However,in the dioecious figs(F.semicordata,F.auriculata and F.hispida),the pollination and oviposition behaviors of pollinator were not separated obviously,even the times of pollination and oviposition behaviors were significantly different between the male figs and female figs.In general,the female figs are better suited for pollination,and the male figs are better suited for oviposition.3.The pollinators that naturally arrived to the figs at the receptive stage usually had larger body size and more egg loads than the pollinators freshly emerged.After the pollinator entered the figs(F.racemosa),the 95% of eggs were laid in the first 6 hours,and the 80% of pollen grains were transferred in the second 6-24 hours.Finally,the matching number of offspring and seeds were produced by the figs.The results confirmed that it existed the time distribution and the balance of reproduction between pollination and oviposition for pollinator.In this study,it is the first time to report that the pollination and oviposition behaviors of Ceratosolen sp.on F.racemosa were separated,which first oviposited and then pollinated female flowers.Moreover,the pollination and oviposition behaviors of pollinators were similar and performed continuously in the male and female figs,but what makes the different breeding fates of female flowers in dioecious figs need further study.The results provide scientific basis for understanding the stability of fig-fig wasp mutualism.