Mechanisms of multimodality: androgenic hormones and adaptive flexibility in multimodal displays

Abstract

Multimodal displays are a long-standing fascination of behavioural biologists because many signallers can adjust display architecture or switch signalling modality, often to exploit the advantages or avoid the disadvantages of a particular signalling environment. Yet, how such adaptive flexibility occurs remains poorly understood. Here, we argue that studying the endocrine modulation of multimodal signal production can close this knowledge gap. We first highlight a concept well known to behavioural endocrinologists that sex steroid hormones, and in particular androgens, can mediate the integration of multiple signalling traits at the organismal level. We then hypothesize that endocrine responses also play a role in maintaining flexibility in multimodal displays over time and space and may be key in responding quickly to fluctuating environments. To support these ideas, we use as our major example our own work in ‘foot-flagging’ frogs, Staurois parvus. We provide an overview of prior work on multimodal signalling in this species, as well as initial data from network analyses that point to androgen-mediated adaptive shifts in multimodal display architecture. We conclude by suggesting future work to further elucidate the connections between the signalling environment, androgenic hormones and behavioural flexibility in multimodal communication. • Multimodal sexual displays evolve in fluctuating environments. • We provide a framework for exploring endocrine regulation of multimodal displays. • Androgens may play a role in adaptive shifts in multimodal display architecture.