ARTICLE | ONLINE NOW, 109935

Acute exposure to caffeine improves foraging in an invasive ant

Henrique Galante 4, Massimo De Agrò, Alexandra Koch, Stefanie Kau, Tomer J. Czaczkes
Show footnotes Open Access
Published:May 23, 2024
DOI:https://doi.org/10.1016/j.isci.2024.109935

Highlights

• Intermediate doses of caffeine resulted in 38% shorter foodward foraging visits
• Improvement was driven by an increase in path straightness rather than speed
• Caffeine had no effect on ant homing behavior
• Adding caffeine to baits could increase recruitment and consumption of toxic baits

Summary

Argentine ants, Linepithema humile, are a particularly concerning invasive species. Control efforts often fall short likely due to a lack of sustained bait consumption. Using neuroactives, such as caffeine, to improve ant learning and navigation could increase recruitment and consumption of toxic baits. Here, we exposed L. humile to a range of caffeine concentrations and a complex ecologically relevant task: an open landscape foraging experiment. Without caffeine, we found no effect of consecutive foraging visits on the time the ants take to reach a reward, suggesting a failure to learn the reward’s location. However, under low to intermediate caffeine concentrations ants were 38% faster with each consecutive visit, implying that caffeine boosts learning. Interestingly, such improvements were lost at high doses. In contrast, caffeine had no impact on the ants’ homing behavior. Adding moderate levels of caffeine to baits could improve ant’s ability to learn its location, improving bait efficacy.

Graphical abstract


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