Floral characteristics of Ficus curtipes and the oviposition behavior of its pollinator Fig wasp

Abstract

Figwasps (Hymenoptera: Agaonidae) can only develop inside the fruit (figs) offigtrees (Moraceae; Ficus spp.). Figs are hollow, rounded structures lined on the inside by numerous tiny flowers. To lay their eggs, female fig wasps enter the figs and typically walk around on a platform of stigmas (synstigma) from which they insert their ovipositors through the stigmas and down the styles before reaching the ovules, where they oviposit. Previous studies have described fig wasp oviposition behavior in those Ficus species with a synstigma and have related ovipositor lengths to style lengths accordingly. Here, we show that this oviposition pattern is not universal within Ficus and that variation in fig architecture leads to the modification of oviposition behavior. Figs of the monoecious Asian fig tree F. curtipes and relatives (subsection Conosycea) lack a synstigma, which is replaced by an irregular mass of elongate stigmas. The ovipositor of the pollinator Eupristina sp. is sufficiently long to reach all the ovules. Despite this, and unlike other fig wasps, they do not oviposit via the top of the stigmas, but insert their ovipositors through the stigmal bases. Oviposition behavior in fig wasps is therefore responsive to variation in floral structure within their host figs.