Meeting Abstract

79.2  Tuesday, Jan. 6  Fighting is metabolically costly for both winners and losers in the convict cichlid fish Amatitlania nigrofasciata COPELAND, D.L.*; EARLEY, R.L.; University of Akron; University of Alabama dlcevo1@yahoo.com

The success of individuals who engage in multiple contests over a short period may depend heavily on physiological adaptations associated with energy mobilization. We examined post-fight muscle lactate, liver glycogen and both plasma and liver glucose levels in convict cichlid fish Amatitlania nigrofasciata. Lactate accumulation can negatively impact skeletal muscle performance while glycogen and glucose reflect energy mobilization. Based on a body of game theoretical literature, we predicted that losers would accumulate more muscle lactate and/or mobilize carbohydrate stores faster than winners, which could ultimately lead to their submission. We staged 32 contests between size-matched males. We quantified aggression as duration and frequency of mouth wrestling between males, which constitute the most highly escalated behaviors of the cichlids fighting arsenal. We also quantified threat displays and circling behavior, and concentrations of post-fight androgens and cortisol. In both winners and losers, we found a significant, positive relationship between lactate accumulation in the caudal muscle and the frequencies of mouth wrestling and threat display, and contest duration. The slopes of these regressions were statistically indistinguishable between winners and losers. We found no evidence that status (winner, loser, control) impacted any of the physiological parameters. These results demonstrate that, of the physiological responses to fighting, metabolic costs are most pronounced. Independent of social status, intense contests elicit significant lactate production in the muscle, which could preclude fatigued fighters from engaging in, or winning, future contests.