Behavior, behavioral syndromes, and metabolism: the effects of artificial selection for death-feigning on metabolic rate

Death-feigning, or thanatosis, is an anti-predator behavioral strategy in many animals. Because individuals remain immobile while feigning death, individuals with longer durations of death feigning often show lower locomotor activity. Thus, metabolic rate, which is closely related to locomotor activity, may also be related to the intensity of death feigning. If there is a genetic correlation between death feigning and metabolism, metabolic rate may respond to selection on death-feigning behavior. Here, we tested for a relationship between metabolic rate and death-feigning using replicated populations of the red flour beetle (Tribolium castaneum) subjected to artificial bidirectional selection on the duration of death-feigning behavior. The results indicated that metabolic rate did not differ between populations selected for increased or decreased death feigning, although locomotor activity was significantly different between these treatments; populations selected for reduced death-feigning durations tended to be more active. These results suggest that death-feigning behavior is not genetically correlated with metabolic rate in T. castaneum.