Researcher(s)
- Paul Schultz, Biological Sciences, University of Delaware
Faculty Mentor(s)
- Lisha Shao, Biological Sciences, University of Delaware
Abstract
Socialization is essential, which is not only true for humans, but is also seen in nearly every reach of the animal kingdom. While human ecology is a social ecology, the effects of how extreme social density impacts an individual’s well-being remains unclear. Here we used Drosophila melanogaster, the common fruit fly, as a model organism to answer this question. We hypothesize that social isolation may cause negative outcomes by inducing stress pathways that intersect with essential behavioral and physiological functions. We tested the hypothesis by investigating the feeding behavior, which is regulated by both the animal’s internal state and the environmental factors. To empirically determine feeding behavior, the fly was fed dyed food for 24 hours. Through measuring the concentration of dye both inside and outside (excretion) the fly, it was possible to extrapolate the quantity eaten. We found that socially isolated female virgin fruit flies ate significantly less than group-housed flies. To reveal the mechanisms underlying the altered behavior, we first defined the necessary length of time for social conditioning and found that acute (3-day) and chronic social (5-day) isolation may have distinctive regulation in fly’s feeding behaviors. Furthermore, we tested the reversibility of the behavior change. Our results showed that the change in feeding behavior after chronic isolation was reversed after 3-day regrouping, suggesting plasticity in fly’s reaction and adaptation to social densities. Importantly, we found that key metabolites were decreased in socially isolated flies. Further investigation on the causal relationship between metabolic and behavioral changes will provide more mechanistic insights into the regulation of feeding by social density. Overall, our studies shed light on how social stress regulates brain functions and behaviors.