Meeting Abstract

9.4  Sunday, Jan. 4  Brood value affects the endocrine response of a wild teleost fish to a standard stressor during parental care O’CONNOR, Constance/M*; YICK, Claire/Y; GILMOUR, Kathleen/M; VAN DER KRAAK, Glen; COOKE, Steven/J; Carleton University, Ottawa; Carleton University, Ottawa; University of Ottawa, Ottawa; University of Guelph, Guelph; Carleton University, Ottawa coconno4@connect.carleton.ca

For animals with multiple lifetime reproductive opportunities, the value of a current brood will influence optimal trade-off decisions between the current brood and future reproductive opportunities. One of the key mechanisms underlying these trade-offs decisions is the endocrine system. There is evidence that the endocrine state required for the maintenance of parental care is incompatible with the endocrine state associated with a stress response. When faced with a challenge during parental care, brood value should therefore influence whether an animal responds with an acute stress response at the expense of the current brood, or attenuates the stress response at the potential expense of survival and future reproduction. We tested this hypothesis in a wild teleost fish. The smallmouth bass, Micropterus salmoides, is a long-lived species that provides annual male-only parental care. Parental males show differences in energy expenditure and parental investment both in relation to brood size and brood age. In an initial set of experiments, we manipulated brood size at the onset of parental care, and subsequently measured the cortisol and testosterone levels of the parental males after a standard restraint stressor. In a second set of experiments, we measured the cortisol and testosterone levels of the parents after a standard restraint stressor across the parental care period. This is the first study that examines differential stress responses in relation to life-history trade-offs in a fish.