Ovipositing Pattern of the Fig Wasps and Its Effect on the Offspring Sex Ratio
榕小蜂的产卵模式及其对子代性比的影响

In this study, we experimentally examined the ovipositing sequence of the pollinator Ceratosolen fuscicep, non-pollinating wasp Platyneura mayri of Ficus racemosa and non-pollinating wasp Acophila sp.1 and Wakerella benjamini of Ficus benjamina in Xishuangbanna from Apr. 2006 to Jun. 2007. For the pollinating fig wasps, we injected ether into the receptive fruits with different time intervals after introducing the fig wasps, killing the fig wasps; for the non-pollinating fig wasps, we manually controlled ovipositing time length through organdy bags. After the treated fruits developed to be mature stage, we collected the adult wasps, and then analyzed and compared the offspring sex ratio under different ovipositing time length. The data showed that fig wasp C. fuscicep, P. mayri and Acophila sp.1 firstly oviposit their male offspring. The male offspring was much higher than female, if the mother wasps only oviposited one hour, whist the female offspring will be increased with the increase of oviposting time of mother wasps and the female offspring will be much higher than male offspring when the mother wasps could sufficiently oviposit their offspring in these three fig wasps. These results partly explain that the female offspring sex ratio decrease with increase of number of foundresses. However, the ovipositing sequence of Wakerella benjamini randomly oviposit their eggs and the sex ratio is about 1:1. Our results here imply that the ovipositing sequence and ovipositing time length of mother wasps might be of the most important factors determining the offspring sex ratio of fig wasps.