An agent-based model shows zombie ants exhibit search behavior

J Theor Biol. 2021 Jun 1;110789. doi: 10.1016/j.jtbi.2021.110789. Online ahead of print.

Abstract

Parasites can alter the behavior of animals. Such alterations could be a byproduct of infection or actively controlled and directed by the parasite. Ants infected with zombie ant fungi (Ophiocordyceps sp.) show behavioral changes culminating in the ant dying while biting into vegetation. To investigate the influence of the parasite on behavioral changes, we created an agent-based model that provides a prediction of how fungal infected ants move before death. The model shows how alterations in movement, such as an increased turning rate, within the normal range of ant behavior, can lead a host from the nest to the underside of a leaf. This demonstrates the simplicity in how such behavioral changes could evolve, as the fungal parasite could benefit from the natural behavior of the host, contesting a hypothesis of highly directed manipulation.

Keywords: animal movement; fungal pathogen; individual-based model; parasite manipulation; social insect.