Research

What is the cost of reproduction and territoriality?

We study how animal compete and reproduce using a physiological and evolutionary perspective. Our research is trying to address two key questions: (i) How do organisms maintain energy balance and cellular homeostasis during reproduction and territorial defense, and (ii) how does aggressive competition influence evolutionary diversification? We use a combination of behavioral experiments, oxidative stress measurements, mitochondrial bioenergetics, and gene expression approaches. Our work is also relevant to the biomedical field given the intimate link between psychosocial stress, oxidative stress, and disease.

The research is focusing on the highly social cichlid fish Astatotilapia burtoni, a model species in ethology and social neuroscience. This species has a lek-like social system in which dominant males defend a territory where they court females who care for their offspring in the form of mouthbrooding. Subordinate males are non-territorial and lack bright coloration. The behavior of these cichlids can be readily tracked and manipulated in replicated lab communities. Our research is funded by NIH and ALAAS.

Research projects

(i) How does social stress arising from territorial aggression impact patterns of oxidative stress?

Rank within a dominance hierarchy influences access to resources and impacts health in numerous social species. Holding a rank can be a source of chronic stress resulting from prolonged subordination or costly interactions to maintain high dominance status. In our lab, we study how social rank and social stability influences oxidative stress (occurs when reactive oxygen species overwhelms antioxidant system) in East African cichlids. More recently, we began studying this in the brain because of the relevance of oxidative stress in nervous system disorders. 

(ii) How do mothers manage the cost of reproduction?

Cichlid females care for their offspring in the form of mouthbrooding, which is extremely costly behavior because mothers cannot eat during mouthbrooding for over two weeks! We have previously shown that egg production and mouthbrooding results in oxidative stress. In this project, we will study behavioral and physiological strategies that mouthbrooding females use to manage the cost of reproduction, including changes in antioxidant defense and mitochondrial function.

(iii) How does male-male competition influence diversification? 

Competition between males for reproductive access to females can influence the process of speciation and population differentiation. For example, more intense competition between similar phenotypes would favor rare phenotypes, facilitating the evolution of variation in competitive traits (e.g. male coloration, weapons) and contributing to the buildup of reproductive isolation (i.e.. speciation). We are interested in understanding the link between frequency dependent social interactions and various components of fitness, such as reproductive success, immune function, and oxidative stress. More recently, our lab has taken an interest in studying how social experience influences aggression biases.