Positive genetic correlations between life-history traits and death-feigning behavior in adzuki bean beetle (Callosobruchus chinensis)

Usually, several traits in organisms are genetically linked with each other; thus, correlated responses to selection are generally observed. Anti-predator behaviors may be genetically correlated with other traits such as life-history. We compared the life-history traits of individuals derived from two regimes artificially selected for the duration of death feigning in the adzuki bean beetle, Callosobruchus chinensis. The two-way selected regimes include the L-lines with stronger intensity (longer duration and higher frequency) and the S-lines with weaker intensity (shorter duration and lower frequency) of death feigning. L-lines exhibited greater longevity, higher rates of emergence, laid bigger eggs and greater reproductive effort, and also had a tendency of faster development. Fecundity was not significantly different between L- and S-lines. These results provide the novel possibility that death feigning is a potentially advantageous anti-predator behavior that, through a positive genetic correlation with some life-history traits, can bring a higher fitness to an individual adopting this behavior. This novel aspect might explain why death-feigning behavior is prevalent in various taxonomic animal groups.