Modelling information exchange in worker–queen conflict over sex allocation

Abstract

We investigate the conflict between queen and worker over sex allocation, specifically the allocation of the queen's eggs between workers and reproductives and the allocation of the reproductive eggs between male and female. In contrast to previous models, we allow workers to observe and use information about the strategy of the queen. We consider three conflict models: simultaneous (no information exchange), sequential (a one-way information exchange) and negotiated (an iterated two-way information exchange). We find that the first model produces sex ratios intermediate between the classic queen (1:1) and worker (1:3) optima. The second model, in which the worker has information about the queen's decisions, produces a different result and one that is somewhat counter-intuitive in that the sex ratios are less female-biased than for the other two models, and in fact are often male-biased. The third model predicts sex ratios intermediate between the first two models. We discuss how these findings may shed new light on observed sex allocation patterns in social insects and we suggest some experimental tests.