Current Research Projects
Use of immunomarking techniques to study nutrient distribution, foraging ecology, and spatial colony structure in ants
We use a combination of laboratory and field tests to investigate the foraging ecology in urban ants at ecological scales ranging from the population to the community. Specific research topics include the effect of colony spatial structure on food distribution, trophallaxis and feeding relationships within colonies, food preferences, and tracking trophic links in predator-prey interactions. To track the movement of food we use protein marking (rabbit immunoglobin) coupled with the highly sensitive DAS-ELISA (double antibody sandwich enzyme-linked immunosorbent assay). The primary goal of these efforts is to understand the mechanisms and pathways of food distribution in ant colonies as dictated by various social and ecological factors. In addition, the research is designed to provide a framework for designing innovative integrated approaches (IPM) for the management of pest ants.
Colony and population genetic structure in the black carpenter ant, Camponotus pennsylvanicus using microsatellite markers
Camponotus is one of the largest ant genera, yet virtually no information exists on the spatial, social, and genetic structure of Camponotus colonies. The black carpenter ant, Camponotus pennsylvanicus, is the most abundant species it the United States and is ecologically and economically important. However, their cryptic nesting and foraging habits have hindered our understanding of many important features of their life history and population dynamics. To address this gap we are using molecular genetic markers - microsatellites and mtDNA - to generate the fine-scale genetic structure of colonies and populations of C. pennsylvanicus and to characterize the sociogenetic structure of colonies in different habitats.
Evolutionary shifts associated with the transition of native ants into invasive urban pests
Human modification of the environment inadvertently creates perfect habitat for a wide range of urban pests. As a result, some species adapt to take advantage of the changing landscape. The odorous house ant (OHA), Tapinoma sessile, is a native ant species that is very opportunistic and highly variable in its social structure. In its natural habitat, OHA is a low-key species comprised of small monogynous and monodomous colonies. In invaded urban areas, OHA exhibits extreme polygyny and polydomy and becomes a dominant invasive pest. We are using behavioral, genetic, and ecological approaches to understand the evolutionary forces driving this remarkable transition. Specific research questions include: (1) the effect of environmental factors on OHA colony size and distribution, (2) the effect of OHA supercolonies on other native ant species, and (3) changes in life history traits and colony sociogenetic structure following transition to supercolonies.
The ecology of polydomy in ants
Ant colonies function at various organizational levels, ranging from colonies that occupy only one nest (i.e. monodomy) to colonies that occupy multiple nests, a condition known as polydomy. In polydomous colonies, nests are separated spatially, but connected socially by the exchange of workers, queens, brood, and food. We are investigating the factors that promote polydomy such as the patchiness of food resources, distance between patches, nest site availability, and pressure from competing species. Furthermore, we are investigating the consequences of spatial distribution of nests on colony social organization and reproductive allocation, colony genetic structure, food distribution, and nestmate recognition. Currently we are using four facultatively polydomous ant species as model systems: odorous house ants, Tapinoma sessile; Argentine ants, Linepithema humile; Pharaoh ants, Monomorium pharaonis, and black carpenter ants, Camponotus pennsylvanicus.