Supplementary Material for: Fungal Solutions to Parasitizing Ant Societies
Fungi in the Ophiocordyceps (Ascomycota, Hypocreales) genus are remarkable for their ability to manipulate an ant host to leave the nest and die biting into vegetation, hence creating a ‘zombie ant’. This dissertation explores Ophiocordyceps ant parasites in natural field conditions. Ant colonies have a suite of behaviors that protect the colony from disease and I explore how host manipulation helps the parasite evade colony defenses. I compare three zombie ant systems from different areas of the phylogeny, providing insight into the evolutionary innovations and adaptations of this fungal group. First, in chapter 2, I examine the foraging dynamics of a commonly infected ant, discovering that foraging ants are at unequal risk of picking up spores. After creating a model in chapter 3 to predict how zombie ants move in this system, I compare zombie and uninfected ant movement to demonstrate how zombie ant cadavers end up surrounding the main foraging trails. In chapters 4 and 5, I investigate two other zombie ant systems featuring different host and parasite species. I look into how foraging ants interact with the zombie ant cadavers and finding that cadavers are sometimes removed by conspecifics. My observations show how the ant host can fight back against the parasite. Overall, my dissertation illustrates the fascinating arms race between hosts and parasites, and in particular, the conflicting forces of a highly specialized parasite and a deeply protected altruistic society.