Antipredator behaviour of invasive geckos in response to chemical cues from snakes

Abstract

Antipredator behaviours and the ability to appropriately assess predation risk contribute to increased fitness. Predator avoidance can be costly; however, so we expect prey to most strongly avoid predators that pose the greatest risk (i.e., prey should show threat sensitivity). For invasive species, effectively assessing the relative risk posed by predators in the new environment may help them establish in new environments. We examined the antipredator behaviour of introduced Asian house geckos, <i>Hemidactylus frenatus</i> (Schlegel), by determining if they avoided shelters scented with the chemical cues of native predatory snakes (spotted pythons, <i>Antaresia maculosa</i> [Peters]; brown tree snakes, <i>Boiga irregularis</i> [Merrem]; common tree snakes, <i>Dendrelaphis punctulata</i> [Grey]; and carpet pythons, <i>Morelia spilota</i> [Lacépède]). We also tested if Asian house geckos collected from vegetation vs. anthropogenic substrates (buildings) responded differently to the chemical cues of predatory snakes. Asian house geckos did not show a generalised antipredator response, that is, they did not respond to the chemical cues of all snakes in the same way. Asian house geckos avoided the chemical cues of carpet pythons more strongly than those of other snake species, providing some support for the threat-sensitivity hypothesis. There was no difference in the antipredator behaviour of Asian house geckos collected from buildings vs. natural vegetation, suggesting that individuals that have invaded natural habitats have not changed their antipredator behaviour compared to urban individuals. Overall, we found some evidence indicating Asian house geckos are threat-sensitive to some Australian predacious snakes.