Comparison of reproductive strategies in two externally ovipositing non-pollinating fig wasps

Abstract

The reproductive strategies of Walkerella sp.1 associated with Ficus curtipes and Walkerella sp.2 associated with Ficus benjamina were investigated. Both species oviposited from outside the fig wall. Walkerella sp.1 was the first non-pollinating fig to oviposit on Ficus curtipes and began to do this ten days after figs syconia began to develop. The larvae of Walkerella sp.1 were only found in the most external ovary layer of the fig. Walkerella sp.2 starts ovipositing after several other non-pollinating fig wasps have already laid their eggs in F. benjamina. The progeny of Walkerella sp.2 are distributed in the external ovary layer, the middle ovary layer, and/or the inner ovary layer of the figs. However, more than a quarter of the offspring were found in the most external layer and only a few in the inner layer. Experimental studies proved that the two Walkerella species are gall formers. In both manipulated figs and in natural figs, the sex ratios of Walkerella sp.1 and Walkerella sp.2 were female-biased. In Walkerella sp.2, the overall sex ratio increased with the proportion of figs parasitized in a crop, but this was not the case for Walkerella sp.1. Females of both Walkerella species appear not to have information about the patches on which they oviposit because sex ratios of both species decreased as brood sizes within individual figs increased and foundresses of both species were able to lay clutches containing a single male egg and several female eggs.