Department of Entomology
University of California, Riverside
Research in the Purcell lab is broadly focused on how and why sociality evolves and on the functional consequences of social variation. We investigate these questions in arthropods: social insects exhibit a tremendous diversity of social systems and serve essential functions in global ecosystems. To pursue these research avenues, we combine complementary approaches from population genomics, biogeography, experimental ecology, and animal behavior. Some of our recent discoveries and future research questions are described below.
We recently identified a large portion of the genome that is perfectly associated with a social trait (queen number) in a European ant species. How common are these supergenes (or "social chromosomes") across ants and other social insects? Do these structures help to drive evolutionary transitions in social complexity, or do they emerge later to reinforce social systems? How is this genetic polymorphism maintained in natural populations?
photo by: Daniel Pierce
Many social arthropods, including spiders, native bees, and ants, exhibit consistent patterns in the distribution of social variation along environmental gradients. In ants and spiders, for instance, simpler societies consisting of a mother and offspring are common in cooler environments (i.e., at high altitude or latitude), whereas more complex societies containing multiple families are more prevalent in warm, stable habitats. Will climate change affect local ant and bee communities and their social strategies along these geographic gradients? How will the changing climate interact with invasive species (e.g., Argentine ants) to shape future insect communities?
We are harnessing the variation in social systems found along environmental gradients to examine ecological factors associated with sociality and to carry out experiments designed to isolate the causes of these biogeographic patterns. We have used a variety of approaches, including reciprocal transplant and common garden experiments, to identify ecological factors that influence sociality. In particular, we ask which environmental variables shape focal social traits, and what mediates their influence? Would changes in any of these factors cause shifts in the behavioral or ecological strategies of resident species?
Photo by: Dumas Galvez
Cooperation within societies can enable groups to perform tasks that would be impossible for an individual. We investigate the synergistic effects of social behavior in several contexts: by studying the fascinating physical structures that social insects form by linking their bodies together (e.g., ant rafts) and by exploring how social insects increase their ability to resist disease by working together. We are also combining this research on social immunity with tests of potential bio-control agents on invasive ant species. Are groups of ants able to help one another resist infection, and how can we circumvent or manipulate social immunity measures, such as grooming and food sharing, to increase the efficacy of bio-control mechanisms?