Resource allocation: a conflict in the fig/fig wasp mutualism?

Conflicts of interest are omnipresent between mutualist species. In the monoecious fig/pollinator wasp mutualism, each female flower produces either a seed or a pollinator offspring (which has fed on a single seed). Pollen from a syconium (i.e. fig, a closed urn‐shaped inflorescence) is only dispersed by female pollinator offspring born in this syconium. Thus the fig tree is selected to produce both seed and pollinator offspring whereas for the pollinator there is no short term advantage in seed production. Using controlled pollination experiments (pollen injection, and foundress introduction), we show that 1) The relative proportion of seeds and pollinator offspring produced (i.e., the effective allocation between female and male function) depends mainly on the number of foundresses that entered the syconium. 2) Many female flowers within every syconium mature neither a seed nor a wasp (from 25% to 33%). 3) All the female flowers within a syconium that are not vacant at maturity have the potential to produce a seed, and at least 80% of them can produce a pollinator. Several hypotheses concerning mechanisms that govern the partitioning between seed and wasp production are discussed, and their evolutionary consequences are considered.