Endurance in excercise is associated with courtship call rate in decorated cricket, Gryllodes sigillatus

Abstract

Question: Is sexual signalling (courtship call rate) determined by physiological fitness (energy metabolism at rest), endurance during physically demanding activity, an aspect of immune defence (lytic activity) or body mass? Organism: Pedigree laboratory population of decorated crickets (Gryllodes sigillatus). Methods: Behavioural trial of male courtship call rate and measurements of males’ physiological performance. Covariance analysis exploring the determinants of courtship call rate. Results: We found that endurance was strongly positively associated with the courtship call rate. However, neither the lytic activity nor the resting metabolic rate correlated with courtship call rate. Together with body mass and family effects, endurance explained over 77% of the variance in courtship call rate. Hence, only physically fit individuals can perform sexual displays well.