Behavioural variation and plasticity along an invasive ant introduction pathway

Area of Science:

• Ecology and Evolutionary Biology
• Invasive Species Biology
• Animal Behavior

Background:

• Introduced species can change due to plasticity, selection, and drift.
• The introduction process may select for traits promoting invasiveness.
• Argentine ants (Linepithema humile) are a widespread invasive species.

Purpose of the Study:

• To test if behaviors linked to invasiveness (foraging, aggression) are selected during invasion.
• To compare traits between native (Argentina) and introduced (California, Australia, New Zealand) Argentine ant populations.
• To assess behavioral plasticity in response to resource availability and octopamine.

Main Methods:

• Established experimental colonies in native and introduced regions.
• Manipulated carbohydrate availability and octopamine levels.
• Measured foraging activity (exploration, exploitation) and interspecific aggression.

Main Results:

• Foraging activity varied among populations but not consistently with invasion.
• Limited carbohydrates increased exploitation and decreased aggression.
• Octopamine increased foraging and aggression (when sugar-deprived); plasticity did not differ along the introduction pathway.

Conclusions:

• No support found for selection of invasion-associated behavioral traits along the introduction pathway.
• No clear evidence links the introduction process to variation in behavioral plasticity.
• Mechanisms promoting behavioral variation function similarly in native and introduced ranges, challenging assumptions of enhanced performance in invasive populations.