Function Of Active Pollination Behaviour In Ficus Hispida And Its Pollinator Mutualism

The two cooperative partners of the fig-fig wasp mutualism interact with each other by pollination service of the fig-pollinating wasps. The pollination behaviors of fig wasps consist of active and passive pollination, and active pollination is considered to be evolved from passive pollination. Due to their short lives, to pollinate figs actively is a waste of energy and time for fig-pollinating wasps, and thus is of no benefit to them. However, there are many genus of fig-pollinating wasps became active pollination from passive pollination in the whole evolutionary history of the mutualism. It indicates that active pollination may be beneficial to the mutualism, and active pollination is a trend of evolution.In the present study, by using the male tree of Ficus hispida L. and its pollinating wasp Ceratosolen solmsi Mayr, we treated the foundresses into pollen-baring or pollen-free groups, and tried to explore the difference of the fig wasp offsprings and the figs. We analyzed the offspring numbers, sex ratios, larval mortalities, body sizes, gall numbers, the dropping rates of the figs, the female floret numbers and the fig diameters in order to test whether active pollination has an effect in the figs of F. hispida and its pollinators.Our results shows that active pollination has an obvious effect on the fig-pollinating wasps, nevertheless not on the figs. Compared to the pollen-free fig-pollinating wasps group, the larval of the pollen-bearing foundresses have a lower mortality and relatively bigger body sizes. There is no difference in the offspring sex ratios between both groups, however, considering the correlation of mortality and sex ratio, active pollination may affect offspring sex ratio indirectly. Both groups have similar gall numbers, indicating that it is the fig wasp itself not the pollen has influence on the gall numbers. Both groups do not have divergent dropping rates, which gives us a hint that the oviposition of fig-pollinating wasps into the ovaries of fig female flowers can avoid fig dropping. There is no difference in fig diameters and total numbers of female florets between both groups, and the clear correlation between the fig diameters and the total numbers of female florets suggests that the factor affecting the female flortes is the fig itself.Combined with previous studies, our results shows that active pollination does have an obvious effect on the mutualism of fig-fig wasp. The fig-pollinating wasps which do not pollinate the fig will suffer from a punishment, suggesting the existence of host sanctions in the mutualism. Between both participators of the fig-fig pollinating wasps mutualism, fig plays a key role and dominates the mutualism, which helps keep the mutualism steady and developing.