Evolution of animal chemical communication: Insights from non-model species and phylogenetic comparative methods

Chemical communication is probably the oldest, most ubiquitous form of information exchange in the natural world, spanning all three domains of life. While excellent sociobiological and behavioral ecological research has been conducted on the form and function of chemical signals in animals, we still know remarkably little on their evolution. Besides, much of our understanding of chemical signal diversity is restricted to insects, since studies on chemical communication in vertebrates are relatively scarce. In this review, I introduce the key concepts of animal communication and expand on the past, present, and future of research in chemical communication. When doing so, I highlight the current gaps in our knowledge on the evolution of the chemical communication system in animals, whilst emphasizing the heavy research bias towards lepidopterans. Here, I detail the benefits of using phylogenetic comparative methods to identify the motors and brakes that guide the evolution of chemical signals and chemical sensory systems. Moreover, I point out that focusing on non-model species in chemical ecology, specifically lizards, can provide valuable insights into how vertebrate chemical signals evolve, and how biological systems responsible for sending and receiving signals co-evolve with signal design. Lastly, I present a case study on lacertid lizards, demonstrating the possibilities of the phylogenetic comparative approach and the use of non-model species to study the evolution of animal chemical communication systems.