The impact of urbanization on learning ability in an invasive lizard

The process of urbanization brings about striking shifts across all levels of an ecosystem from habitat structure, resource availability, predator-prey relationship and climatic condition. As these ecological alterations are typically drastic and rapid, presenting wildlife with selective pressures that differ dramatically from those under which they naturally evolved, individuals must be either adjusted or excluded. One factor hypothesized to facilitate the successful exploitation of urban areas is cognition. It is predicted that enhanced cognitive function is strongly selected as it mitigates the presumably novel and often unpredictable conditions within cities by enabling the rapid perception of, and response to, changes in environmental cues. There is much evidence in support of this notion. However, this research focuses almost entirely on avian species. Here, we compared the learning performance between urban and natural populations of a widespread reptile species in eastern Australia, the delicate skink (Lampropholis delicata), to determine whether the positive relationship between cognitive ability and urbanization is a broader phenomenon. Lizards were exposed to a standard Y-maze designed to measure their ability to learn to discriminate between safe and unsafe artificial refuges, a key problem that delicate skinks are likely to confront in urban environments. Counter to our predictions, no differences in any learning metric between urban and natural lizard populations were detected. We propose that similarity in environmental conditions in both habitat types may have resulted in a lack of selection for enhanced cognitive function in urban lizards.