LOCK AND KEY: Size-matching between male (left) and female (right) genitalia aids mating success in a beetle species. (Scale bar, 2 mm)TEIJI SOTA AND YUTAKA OKUZAKI
The paper Y. Okuzaki, T. Sota, “How the length of genital parts affects copulation performance in a carabid beetle: Implications for correlated genital evolution between the sexes,” J Evol Biol, 27:565-74, 2014. The subject Studies of various species have shown that the size of male genitalia can affect reproductive success. The male carabid beetle Carabus subg. Ohomopterus maiyasanus has a notoriously long copulatory piece—a hook on the root end of its penis. The female, too, can boast an elongated vaginal appendix into which this hook is inserted, and Teiji Sota of Kyoto University in Japan wanted to determine why such size matching may have evolved. The experiment Sota and a colleague evaluated the copulation performance of size-matched and -mismatched carabid beetle couples. Insemination success was ...
