韦氏缩腹榕小蜂的产卵行为

Oviposition behavior of Apocrypta westwoodi

通过对聚果榕上一种非传粉榕小蜂———韦氏缩腹小蜂ApocryptawestwoodiGrandi的产卵行为的详细观察 ,发现该小蜂的产卵行为与具有可伸缩的腹节这种奇特的腹部结构高度相关。该小蜂的产卵过程主要分为 3个阶段 :( 1 )寻找产卵位置 ,小蜂在果面快速搜索 ,以触角或口器触须感受产卵位点 ;( 2 )刺壁 ,小蜂将产卵针垂直于果面 ,刺入果壁 ,进入果腔 ;( 3 )产卵与拉出产卵针。通过与Ansari对于韦氏缩腹小蜂的产卵行为的描述进行比较 ,发现有如下不同之处 :( 1 )在产卵针刚刺入果面时 ,伸长的腹部末端超过头 ,整个伸长的腹部几乎与果面平行 ;( 2 )后足具有下拉产卵鞘的行为 ,并且后足除下拉产卵鞘时与果面分离外 ,均抓住果面 ;( 3 )产卵针不需要产卵鞘支撑时 ,产卵鞘与产卵针分离。

The species-specific mutualism between figs and pollinating fig wasps is an interesting topic for coevolution study. Moreover, many species of non-pollinating fig wasps (NPFWs) can coexist with pollinators in a syconium. The oviposition behavior of Apocrypta westwoodi Grandi, a NPFW with a bizarre telescopic abdomen, was observed on Ficus racemosa in detail via a digital camera. The process of oviposition behavior includes: (1) searching a potential place for oviposition, (2) touching by syconium surface vertically at the beginning, and then piercing into it; (3) ovipositing and withdrawing the ovipositor stylets. Apparently, the telescopic abdomen facilitates its ovipositor stylets penetrating the fig wall and leads to specific oviposition behavior. Our results were compared with previous descriptions on the oviposition behaviors of Apocrypta sp. In comparison with Ansari's description on the A. westwoodi, we found the following differences:(1) while the ovipositor stylets start to pierce into the syconium surface, the retrousse elongated abdomen of the wasp is folded forwards beyond the head and parallel with the syconium surface; (2) the hind legs pull ovipositor sheath down to the syconium surface, then they touch the syconium in the rest of the oviposition process; (3) the ovipositor sheath is separated from the stylets when it does not need to hold the latter.