Endocrine Modulation of Sending and Receiving Signals in ContextDependent Social Communication INTRODUCTION

Synopsis Animal communication requires senders to transmit signals through the environment to conspecific receivers, which then leads to context-dependent behavioral decisions. Sending and receiving sensory information in social contexts, however, can be dramatically influenced by an individual's internal state, particularly in species that cycle in and out of breeding or other physiological condition like nutritional state or social status. Modulatory substances like steroids, peptides, and biogenic amines can influence both the substrates used for sending social signals (e.g., motivation centers, sensorimotor pathways, and muscles) as well as the peripheral sensory organs and central neural circuitry involved in the reception of this information and subsequent execution of behavioral responses. This issue highlights research from neuroethologists on the topic of modulation of sending and receiving social signals and demonstrates that it can occur in both males and females, in different senses at both peripheral sensory organs and the brain, at different levels of biological organization, on different temporal scales, in various social contexts, and across many diverse vertebrate taxa. Modifying a signal produced by a sender or how that signal is perceived in a receiver provides flexibility in communication and has broad implications for influencing social decisions like mate choice, which ultimately affects reproductive fitness and species persistence. This phenomenon of modulators and internal physiological state impacting communication abilities is likely more widespread than currently realized and we hope this issue inspires others working on diverse systems to examine this topic from different perspectives. An integrative and comparative approach will advance discovery in this field and is needed to better understand how endocrine modulation contributes to sexual selection and the evolution of animal communication in general.

Automated summary

Animal communication is influenced by internal physiological states, with modulatory substances affecting the way signals are sent and received, ultimately impacting social decisions such as mate choice. This phenomenon of endocrine modulation in communication is widespread and research in diverse systems from different perspectives is needed for a better understanding of its contribution to sexual selection and the evolution of animal communication.