Unbeatable strategy, constraint and coevolution, or how to resolve evolutionary conflicts: the case of the fig/wasp mutualism

Abstract

Constraints and evolution are central for the resolution of conflicts between mutualistic species and for the stability of mutualisms. However, proximal causes of the benevolence of mutualistic species are often unknown. Monoecious fig species and their specific pollinators are in conflict on the use of fig ovaries, which can either produce one seed or host one pollinator larva. Here, I provide new data showing that, probably because of space constraints during the development of both seeds and wasps, ovaries vary in their quality as a substrate for pollinator development depending on their location within the fig inflorescence. This constraint may be responsible for the stability of the fig/wasp mutualism. Moreover, population density of pollinators and density dependent selection on the pollinators could be sufficient to explain the observed highly variable seed/wasp ratios produced by figs.