Egg deposition patterns of fig pollinating wasps: implications for studies on the stability of the mutualism

Abstract

Summary1. Fig pollinating wasps (Agaonidae) enter Ficus inflorescences (figs), oviposit in some of the flowers, and pollinate in the process. Each larva completes its development within a single flower. In most cases, an inflorescence entered by a wasp will represent its only egg‐laying site. The mechanisms that prevent pollinating wasps from exploiting all the flowers inside a fig are not understood. In this study, hypotheses about flower use by pollinating fig wasps were tested by investigating egg deposition patterns in three species.2. Either one or three wasps were introduced into figs. The figs were then harvested. Serial sections allowed assessment of the presence or absence of a wasp egg in a sample of flowers in each fig. The overall proportion of flowers with eggs and the spatial distribution of eggs were then compared in single wasp figs and three foundress figs.3. In all species, the proportion of flowers with a wasp egg increased with foundress number but less than three‐fold.4. In all species, at least in single foundress figs, flowers near the fig cavity were more likely to receive a wasp egg than were flowers near the fig wall.5. In two species, when the number of foundresses was multiplied by three, there was an increase in the use of flowers near the fig wall, while in the third species, the increase was spread evenly among flowers.6. Factors affecting wasp egg deposition patterns and the potential of investigating such patterns for studying the stability of the mutualism are discussed.