Not so naïve: Ibiza wall lizards acquired the ability to recognize alien snakes in a few years

Alien predators may impose a great threat to naïve preys. Podarcis pityusensis lizards live in Ibiza, a snake-free island until 2003. We studied lizards’ discrimination of scents of two invader snakes: one that predates on lizards, Hemorrhois hippocrepis, and another that does not, Rhinechis scalaris. We compared two populations of P. pityusensis: one from the main island of Ibiza, which coexists with both snakes, and another from the close snake-free islet of Sal Rossa. Lizards from Ibiza recognized the scent of H. hippocrepis and responded with clear antipredator behaviours. However, they reacted to the scent of R. scalaris similarly than to the odorless and the pungent controls. Lizards from Sal Rossa did not recognize any snake species. Thus, lizards can rapidly acquire the ability to react to a totally novel type of predator. There are two possible explanations: (1) rapid evolution of antipredator behavior, and (2) the ability of lizards to learn how to avoid new predators. There have been few generations of lizards since the introduction of snakes, so it would be very fast for evolution to fix antipredator behaviours, although not impossible. Hence, we suggest that these lizards have learnt how to recognize this novel type of predator.

Abraham Mencía, Zaida Ortega & Valentín Pérez-Mellado (2016) in: Moreno-Rueda, G.; Casas, F.; Collantes-Martín, E.; Comas, M.; Megía-Palma, R.; Ochoa, D.; Pintus, E.; Pizarro, M.; Reguera, S.; Rivas, J.M.; Ros-Santaella, J.L. & Zamora-Camacho, F.J. (eds.). 2016. Libro de resúmenes de Eco-Etología 2016, Congreso Internacional de la Sociedad Española de Etología y Ecología Evolutiva. Sociedad Española de Etología y Ecología Evolutiva y Universidad de Granada. Granada. I.S.B.N.: 978-84-617-4865-5.