Description
Parasite virulence (i.e. the harm caused by parasites to host survival and fitness) shapes host-parasite dynamics in both pathogenic and social parasites. While high virulence can paradoxically limit parasite persistence, outcomes are context dependent, sometimes even turning parasites into net mutualists. The fungus-growing ants (Myrmicinae: Attini) are part of a well-studied symbiotic relationship that is vulnerable to exploitation by social parasites. Although experimental work has explored the possible mechanisms behind the network of species interactions, a theoretical understanding of coexistence patterns among multiple social parasites competing for the same host has been missing. In this study, we use a patch occupancy model inspired by fungus-growing attine ants to investigate the dynamics of a community in which multiple socially parasitic species exploit a shared host. We use the model to identify the range of conditions that lead to coexistence of both generalist and specialist parasites with their host, with relative frequencies that correspond to field data. We show that the combined effects of context-dependency, differences in relative virulence, and the degree of specialization are key to explaining the coexistence and parasitism patterns of the community. We also identify the conditions under which the less virulent social parasite emerges as a net mutualist versus a net parasite to the hosts, which allow us to characterize the context- dependent nature of coexistence among competing natural enemies and their hosts.
| Topic | Topic 2: Possibilities for taking context into account in ecological synthesis |
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