The main framework in which we approach research questions is as follows: individuals' traits influence the frequency and nature of their social interactions. Meanwhile, factors of the social environment alter the expression of individual traits. These two factors jointly influence the collective outcomes of social groups, like the execution of collective behaviors and risk of disease outbreaks.
Which traits are important and under what circumstances do they drive disease dynamics?
microbial transmission dynamics in social groups
Tracking bacterial transmission in social groups
To track the transmission of resident microbes between exposed and naive hosts, we collect and isolate bacteria from individuals in situ, label them with fluorescence plasmids, and expose individuals of known behavioral types. This allows us to track horizontal transmission in social groups in the absence of infection-induced sickness behaviors. We have found that transmission can be a product of the phenotypes of both interacting individuals, and the phenotypic composition of the groups in which they reside. We couple these experiments with social network analyses to link transmission dynamics across levels of biological organization.
Collective behavior and disease susceptibility
Social groups are can be confronted with multiple ecological stressors simultaneously. How, then, can groups optimize their phenotypic composition to cope with multiple challenges like foraging, navigation, and disease? We study the relationship between groups' collective behaviors, like foraging and brood care, and susceptibility to infectious disease. Since many of these outcomes share underlying mechanisms, we aim to test whether groups regulate collective traits to optimize group success while minimizing the costs associated with disease.
One focus of the lab is the degree to which variation among individuals generates group differences in disease outcomes. We study microbial transmission in social groups using fluorescence-labeled cuticular bacteria in social spiders and fungal pathogens in acorn ants and fruit flies.
Individual and social determinants of disease risk
Social aggregation of individually marked fruit flies. (inset) Fly infected with entomopathogenic fungus
For many infectious diseases, individuals vary immensely in their risk of infection and in their severity of disease symptoms. This variability is influenced not only by hosts’ traits, but also that of the conspecifics with whom they interact. Another branch of my research focuses on identifying the degree to which individuals’ infection risk is attributable to their own traits vs. factors of their social environment.
Given that parasitism is one of the most common lifestyles among animals, it is surprising that the behavior of parasites is rarely studies directly. This branch of research was spearheaded by Dr. Emily Durkin, a postdoc in the Keiser Lab, and includes research by grad student Elise Richardson. Emily studies the role of parasitic behavior in the evolution of symbioses (using facultative ectoparasitic mites as a model system) and Elise studies host-seeking behavior in lone-star ticks.