Comparative Study of the Pygidial Defensive Systems of Carabid Beetles1

Abstract

Carabid beetles possess a pair of pygidial glands in the apex of the abdomen, and can secrete often by spraying a mixture of chemicals that they are known to employ in escaping from attackers such as predators. In the last decade research has progressed on the carabid defensive systems (Schildknecht et al., 1963, 1968; Eisner et al., 1963, 1970; Moore and Wallbank, 1968; Forsyth, 1972; Benn et al., 1973; Kanehisa, 1973; Scott et al., 1975; Ooshima et al., 1975). They have revealed saturated and unsaturated fatty acids with short carbon chain length, cresols, benzoquinones, salicylaldehyde, and minor components such as hydrocarbons, esters, aldehydes or ketones. Some workers have also discussed the taxonomic correlation with chemical compositions. The pygidial gland systems of carabid beetles were investigated from the chemical compositions and gland morphologies of 132 species in 60 genera collected in the Chugoku district of Japan. This study shows some findings concerning variations of the defensive systems, and may contribute to a more comprehensive account of the defensive secretion and phylogenic relationship within carabid beetles. © 1977, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.