Meeting Abstract
S5-2.2 Saturday, Jan. 5 Social regulation of male reproductive plasticity in an African cichlid fish MARUSKA, K.P.*; FERNALD, R.D.; Louisiana State Univ, Baton Rouge; Stanford Univ, CA kmaruska@lsu.edu
Social interactions and position in a dominance hierarchy can have profound effects on reproductive behavior and physiology, requiring animals’ to constantly integrate environmental information with their internal physiological state. How is salient information from an animal’s dynamic social environment transformed into adaptive behavioral, physiological, and molecular-level changes? The African cichlid fish Astatotilapia burtoni is an ideally-suited model to examine socially-controlled reproductive plasticity because activity of the male reproductive axis is linked to social status. Males form hierarchies where a small percentage of brightly colored dominant individuals have an active reproductive axis, defend territories, and spawn with females, while the remaining males are subordinate, drably colored, do not hold a territory, and have a suppressed reproductive axis with minimal spawning opportunities. These social phenotypes are plastic and reversible, meaning that individual males may switch between dominant and subordinate status multiple times within a lifetime. Here we review the rapid and remarkable plasticity that occurs along the reproductive axis when males change status, a transition that has important fitness implications. Transformations occur in the brain, pituitary, bloodstream, and testes over short time scales, which are evident in overt behavioral modifications as well as physiological, cellular, and molecular level changes that impact reproductive capacity. These widespread changes triggered by a switch in rank highlight the significance of external social information in shaping internal physiology, and emphasize the importance of the vertebrate reproductive system as a substrate for phenotypic plasticity to promote survival and fitness in a dynamic social and physical environment.
