Abstract:The interaction between pollinating fig wasps (Agaonidae) and their host fig trees (Ficus) is a striking example of an obligate pollination mutualism. Successful pollination of fig trees depends on a specific species of fig wasp managing to find figs of the correct host plant, at their correct stage of development. Encounters between receptive figs and their pollinators are attained by figs emitting species-specific volatile chemicals to attract their fig wasps. However, whether and how the choice of fig wasps can be influenced by the characteristics of receptive figs are still controversial. The female phase of Fiucs sermicordata was deemed by whether fig wasps were willing to enter figs, the different developmental phase of male and female figs in receptivity were acquired at the same time by preventing figs from being pollinated by fig wasps, and the diameter of figs was also measured to examined how fig wasps preferences can be reflected by the size, developmental phase and gender of figs. The results showed that figs would keep growing if they were prevented from being pollinated during female phase, smaller figs were more likely to be entered by more fig wasps for both male and female figs, and fig wasps preferred younger figs. Some of fig wasps still chose female figs to enter when both receptive male and female figs were accessible at the same time, although the wasps number was significantly smaller than those of entering male figs. Although the correlation between fig diameter and foundress number was positive within figs in the same developmental phase, such correlation only significant among four treatments of male figs. The results were not consistent with Ficus pertusa and Ficus hispida. These implied that different Ficus species might have different mechanism to control their pollinator's choice during female phase, it is developmental phase in receptivity and the change of chemical volatile as consequence rather than fig diameter has the direct effect on the choice of fig wasps, and fig wasps depend on olfactory rather than visual cue to locate their host figs. The results could help for further understand the stabe mechanisms of fig-fig wasps.
