Mutual wing‐eating between female and male within mating pairs in wood‐feeding cockroach

Abstract

AbstractThe behavior of eating their mates or a part of their mate's body has been studied in sexual cannibalism or nuptial feeding. In these behaviors, only one sex eats the other unilaterally. Within mating pairs of a wood‐feeding cockroach (Salganea taiwanensis), males and females eat the mate's wings each other, which is the first “mutual” case in these behaviors. Because the evolution of sexual cannibalism and nuptial feeding has been explained based on unilaterality, this mutual eating should have a new significance of reproduction. We described this behavior quantitatively and suggest a new hypothesis based on true monogamy, the mating system of S. taiwanensis, copulating with only one mate throughout life. Under true monogamy, the fitness of the mate is the same as own fitness and the pairs are free from sexual conflict. If the wing eating increases the ability of the mate to raise the offspring, this behavior is adaptive for the eater as well as its mate.