How environmental conditions shape the chemical signal design of lizards

1. The signals that animals use to communicate often differ considerably among species. Part of this variation in signal design may derive from differential natural selection on signal efficacy; the ability of the signal to travel efficiently through the environment and attract the receiver’s attention. For the visual and acoustic modalities, the effect of the physical environment on signal efficacy is a well-studied selective force. Still, very little is known on its impact on the chemical signalling system. 2. Here, we take a broad, phylogenetic comparative approach to test for a relationship between animals’ signal chemistry and properties of their natural environment. Our study focused on lizards from the Lacertidae family. 3. We sampled 64 species across three continents and determined the lipophilic composition of their glandular signalling secretions by using gas chromatography-mass spectrometry (GC-MS). For each species, an array of environmental variables of high temporal and s...