Date of Graduation

Spring 2019


Master of Science in Biology



Committee Chair

Alicia Mathis


Dulosis is a type of social parasitism in which a parasitic ant has become dependent on captured workers (hosts) of a closely related species. Dulosis can be either facultative or obligate depending on the degree of dependence on host workers. As parasites become more specialized over evolutionary time, their domestic abilities degenerate until they become unable to survive without the host. However, the ‘lost’ behaviors may display some degree of recovery when host workers are unavailable to do the tasks. The Formica sanguinea group consists of 12 species of parasitic ants, which are all traditionally considered to be facultative parasites. However, recent studies suggest that F. subintegra has characteristics that are more consistent with obligate parasitism. To explore the degree to which F. subintegra has become obligate, this study examined the degree of recovery of foraging and nest excavation behaviors of parasites when hosts are removed. When parasites were isolated from hosts, they spent more time foraging, fed regurgitated food to nestmates (oral trophallaxis) more often, and tended to begin feeding earlier than when hosts were present. Isolated parasites were able to excavate suitable tunnels and engaged in nest building behavior significantly more often than parasites in groups with hosts. These results indicate that F. subintegra demonstrates behavioral recovery in its foraging and nest excavation abilities, and can be considered a less specialized (primitive) obligate parasite. Formica subintegra and its facultative relatives can be used as models for studying the progression of dulotic evolution within a closely related group of social parasites, and may shed light on which factors contribute to the transition from facultative to obligate parasitism.


dulosis, facultative parasite, obligate parasite, social parasitism, Formica subintegra, Formica sanguinea group, ant behavior

Subject Categories

Behavior and Ethology | Entomology | Other Ecology and Evolutionary Biology


© Amber Nichole Hunter

Open Access