Energy Balance, Stress, and Social Behavior

Our lab investigates how animals compete and reproduce using a physiological and evolutionary perspective. We are especially interested in how social and reproductive challenges affect physiological function and shape evolutionary outcomes. We address two key questions: 

1. How do organisms maintain energy balance and cellular homeostasis during reproduction and territorial defense?

2. How does aggressive competition influence evolutionary diversification? 

We focus on the highly social cichlid fish Astatotilapia burtoni, a model in ethology and social neuroscience. Males of this species form lek-like social systems: dominant individuals defend territories and court females, who then mouthbrood the eggs without feeding for over two weeks. Subordinate males lack bright coloration and access to mates. The behavior of these cichlids can be readily tracked and experimentally manipulated in replicated lab communities. In parallel, we also study zebrafish to investigate how alternative stress coping styles relate to brain oxidative stress - complementing our cichlid research on social stress and redox balance in the brain.

To answer our core these questions, we combine behavioral experiments with physiological assays, including measurements of oxidative stress, mitochondrial bioenergetics, and gene expression. Because of the tight connection between psychosocial stress, oxidative damage, and disease, our work also has strong relevance to biomedical research. Our research is currently funded by the NIH, NSF and AALAS.

Current projects

1. Territorial aggression and oxidative stress

In many social species, rank within a dominance hierarchy influences access to resources and health. Maintaining high rank can be metabolically taxing while chronic subordination is also stressful. We study how social rank and social stability influence oxidative stress (occurs when reactive oxygen species overwhelm antioxidant system) in A. burtoni cichlids. We are especially interested in the brain, where oxidative imbalance plays a role in neurodegenerative and psychiatric disorders. 

2. Alternative stress coping styles and brain oxidative status

Animals have different behavioral strategies to cope with stressful situations. Proactive individuals are more risk-seeking, display less behavioral flexibility, and exhibit a lower physiological stress response than reactive individuals. In collaboration with Dr. Wong, we study how alternative coping styles are linked to oxidative damage and antioxidant capabilities in the zebrafish brain.  

3. Maternal strategies for managing the cost of reproduction

Cichlid females invest heavily in reproduction through mouthbrooding, a behavior that prevents feeding for over two weeks. We have previously shown that egg production and mouthbrooding elevate oxidative stress. We are now investigating how females mitigate these costs through antioxidant defenses, mitochondrial adjustments, and behavioral adaptations. 

4. Male-male competition and evolutionary diversification 

African cichlids are a textbook example of rapid, 'explosive' speciation resulting in hundreds of endemic cichlid species that vary in behavior, morphology, and reproductive strategies. In our newly funded NSF project, we study how competition for mating territories influences speciation and population divergence. Specifically, when similar phenotypes compete intensely, rare phenotypes may gain a fitness advantage, promoting trait divergence (e.g., in color) and reproductive isolation. We are now exploring the cognitive and neurogenomic basis of aggression biases, shedding light on the behavioral mechanisms driving evolutionary change. 

5. Environmental enrichment, aggression, and animal welfare 

Environmental enrichment is vital for the welfare of cichlid fish, a key model in behavioral neuroscience. However, structures used for enrichment can promote territorial aggression, posing a risk to the fish that are a target of aggression. In this project (funded by AALAS), we use the cichlid species Astatotilapia burtoni to determine how structural complexity influences aggression, territoriality, and stress, with the goal of developing new recommendations for environmental enrichment.

Images from the lab