Invasive arboreal ants and beleaguered butterflies: Assessing predator-prey interactions using a new ex situ methodology

Controlled and replicable ex situ studies of predator-prey interactions are challenging to design and execute. Predatory ants (and insect predators more broadly) are no exception, as external stimuli for foraging may not be simulated in a laboratory setting, and foraging strategies vary widely across species and colony life stage.

In this project, we conducted behavioral assays to assess interactions between invasive, predatory ants and butterfly eggs and larvae. Invasive ants are known predators of juvenile lepidopterans, but knowledge of which life stages and taxa are at risk of predation by specialist predators is lacking. Understanding the specifics of these relationships can inform conservation efforts and estimate impacts of new and existing invasive predators.

Critical to untangling behavioral patterns was the stimulation of a true, foraging-by-choice response. Using methodologies developed for the display of ants in museums and ant keeping community knowledge, we designed an experimental arena and methodology that effectively stimulated a foraging response in multiple species of ants. This methodology allowed for successful stimulation of foraging and facilitated observation and video recording of interactions. Conclusions made from these data were supported by in situ observations. By considering and designing for an array of external stimuli, foraging behavior was stimulated in the laboratory and enabled controlled observation of ants and their prey.