Nicolas Van Zele

Defensive behaviors and sound warning: Evolution and determinants in snakes

The risk of predation is a major ecological and evolutionary factor. To minimize this risk a diversity of strategies exist either based on camouflage or others on activing signaling and warning the potential predator. Snakes are a a diversified (>3000 species) of strict predators, and some lineages have developed highly specialized venomous functions to subdue their prey. However, snakes are also prey and vulnerable to a large number of predators and the venomous apparatous can also be used for defense. To minimize predation, many snake species use a form of visual aposematism based on striking patterns or coloration. Yet many snake species are also capable of emitting warning sound signals of different nature (hissing, tail vibration, scale rubbing).

While visual signals have been the subject of major scientific interest, warning sound and postural warnings remain much less studied. The mains goal of my work is to improve understanding of the evolution and determinants of warning sounds in snakes. My work will be built on 3 research axes. The first aims to understand the evolutionary determinants of sound and visual warnings by observing the links with the ecological context. The second axis aims to examine and compare sound warnings in a specific lineage of venomous snakes, including in the comparison non-venomous mimetic species. The nature of the signals, potential costs, and effects on target species will be described. Finally, the third axis will be based on the analysis of variations in sound warnings at the intraspecific level between sexes and individuals.

This work is cosupervised by :
Olivier Lourdais (CEBC-CNRS)
Thierry Lengagne in Lyon (LEHNA-CNRS)