Information use during movement regulates how fragmentation and loss of habitat affect body size.

Abstract

An individual's body size is central to its behavior and physiology, and tightly linked to its dispersal ability. The spatial arrangement of resources and a consumer's capacity to locate them are therefore expected to exert strong selection on consumer body size.\n\nWe investigated the evolutionary impact of both the fragmentation and loss of habitat on consumer body size and its feedback effects on resource distribution, under varying levels of information use during the settlement phase of dispersal. We developed a mechanistic, individual-based, spatially explicit model, including several allometric rules for key consumer traits. Our model reveals that as resources become more fragmented and scarce, informed settlement selects for larger body sizes while random settlement promotes small sizes. Information use may thus be an overlooked explanation for the observed variation in body size responses to habitat fragmentation. Moreover, we find that resources can accumulate and aggregate if information on resource abundance is incomplete. Informed movement results in stable resource-consumer dynamics and controlled resources across space. However, habitat fragmentation and loss destabilize local dynamics and disturb resource suppression by the consumer. Considering information use during movement is thus critical to understand the eco-evolutionary dynamics underlying the functioning and structuring of consumer communities.