Body-size dependent difference in death-feigning behavior of adult Callosobruchus chinensis

Size-dependent differences in death-feigning behavior, an anti-predator defense, was examined in the adult adzuki bean beetle, Callosobruchus chinensis (Coleoptera: Bruchidae). A positive correlation was observed between the duration of death-feigning and adult body weight in two replicated experiments. Moreover, under starved condition, beetles reared under high (= lighter beetles) larval density showed significantly shorter longevity and a shorter duration of death-feigning than those reared under low (= heavier beetles) larval density. The body-size-dependent difference in the duration of death-feigning is discussed from the viewpoint of the difference in survival strategies between small and large beetles. Because small beetles don't live as long, they have less time in which to reproduce and so any loss of that short time might be a greater proportion of their fitness lost. This is the first report on the body-size-dependent difference in death-feigning behavior in the adult holometabolic beetle.