Many lizard and amphisbaenian lineages possess follicular glands in the dermis of the inner thighs and/or the area anterior to the cloaca. These tubular glands produce a holocrine secretion that finds its way to the external world through pore-bearing scales (femoral and/or preanal pores). Secretions are composed of proteins and many lipophilic compounds that may function as chemosignals in lizard and amphisbaenian communication. In recent years, we have begun to develop an understanding of the adaptive significance of these secretions, and they are currently thought to play an important role in a variety of processes in these animals. While it appears that epidermal gland secretions function in intra- and interspecific recognition and territoriality, research has focused largely on their role in mate assessment. Despite these recent studies, our knowledge on the true role of the chemicals found in epidermal secretions remains poorly studied, and there are many possible avenues for future research on this topic. Here, we review the literature on the follicular epidermal glands of non-ophidian squamates and provide a first taxon-wide overview of their distribution.
Extreme climate events such as droughts, cold snaps, and hurricanes can be powerful agents of natural selection, producing acute selective pressures very different from the everyday pressures acting on organisms. However, it remains unknown whether these infrequent but severe disruptions are quickly erased by quotidian selective forces, or whether they have the potential to durably shape biodiversity patterns across regions and clades. Here, we show that hurricanes have enduring evolutionary impacts on the morphology of anoles, a diverse Neotropical lizard clade. We first demonstrate a transgenerational effect of extreme selection on toepad area for two populations struck by hurricanes in 2017. Given this short-term effect of hurricanes, we then asked whether populations and species that more frequently experienced hurricanes have larger toepads. Using 70 y of historical hurricane data, we demonstrate that, indeed, toepad area positively correlates with hurricane activity for both 12 island populations ofAnolis sagreiand 188Anolisspecies throughout the Neotropics. Extreme climate events are intensifying due to climate change and may represent overlooked drivers of biogeographic and large-scale biodiversity patterns.
24 October 2014 in Biological Journal of the Linnean Society
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.