Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Temperature effects on exploratory behaviour and learning ability of invasive mosquitofish.

Abstract

The success of an invasive species depends on several factors. One of these is behavioural flexibility, which may promote invasions by allowing invaders to exploit novel foods, habitats and shelters. As behaviour can change rapidly it is an ideal first response to environmental change, including introduction and spread into a new habitat. Behaviour can be modified by learning, thus facilitating adjustment of existing behaviours to accommodate environmental conditions. Climate change is also likely to promote the introduction, establishment, and spread of aquatic invasive species. Temperature in particular is vitally important for ectotherms, directly affecting metabolic rates with consequent changes in behaviour. We evaluated the effects of temperature on the exploration tendency and learning ability of the western mosquitofish, Gambusia affinis. After acclimating fish to warm, medium and cool temperatures we showed that behaviour is affected by temperature, and overall warm-acclimated fish outperformed lower temperature fish. Mosquitofish showed remarkably rapid learning ability exhibiting a clear change within just three days. These effects also differed by fish sex and size. In general, larger females and smaller males were quicker to approach a novel object, while smaller females and larger males were quicker to find food. Warm-acclimated fish learned to adjust to a novel object more quickly and warm-acclimated males showed a faster response to food. In contrast, neither males nor females acclimated to warm temperatures appeared to learn to find the food and it was cool-acclimated females who were both faster to find food and showed the greatest improvement over time. Nonetheless, on both local and global scales, mosquitofishes' rapid learning ability and behavioural flexibility, which allows them to adjust to changing temperatures, is likely to augment their success as invaders in a warming world.