Female-female fighting behavior of the Japanese horned beetle

Two females of the Japanese horned beetle Trypoxylus dichotomus septentrionalis are fighting with each other by head-butting for access to an artificial sap site in the laboratory. Such female head-butting was already described by several studies (Siva-Jothy, 1987; Iguchi, 1996; Hongo, 2003), but no motion pictures was available. This video was utilized in Iguchi (2010). Females of this beetle have no horns. However, their intrasexual fights are intense, so that head-butting produces a clicking sound. Female head-butting behavior is similar to male head-butting behavior. However, studies on female fighting behavior in this species are still rare. References Hongo, Y. (2003) Appraising behaviour during male-male interaction in the Japanese horned beetle Trypoxylus dichotomus septentrionalis (Kono). Behaviour, 140, 501-517. DOI: 10.1163/156853903322127959 Iguchi, Y. (1996) Sexual behavior of the horned beetle, Allomyrina dichotoma septentrionalis (Coleoptera, Scarabaeidae). Japanese Journal of Entomology, 64, 870-875. https://dl.ndl.go.jp/pid/10655126 Iguchi, Y. (2010) Intrasexual fighting and mounting by females of the horned beetle Trypoxylus dichotomus (Coleoptera: Scarabaeidae). European Journal of Entomology, 107: 61-64. DOI: 10.14411/eje.2010.007 Siva-Jothy, M. T. (1987) Mate securing tactics and the cost of fighting in the Japanese horned beetle, Allomyrina dichotoma L.(Scarabaeidae). Journal of Ethology, 5, 165-172. DOI: 10.1007/BF02349949