Defensive Secretion of Lomechusa strumosa, a Myrmecophilous Beetle1,2

Abstract

Myrmecophiles which have developed intimate relationships with their hosts may nevertheless be subject, at times, to aggressive treatment by their formicid benefactors. Thus, it is not surprising that certain myrmecophilous beetles possess well-developed glands which secrete defensive products when they are molested by their normally tolerant hosts. This is particularly true of many species in the staphylinid subfamily Aleocharinae, a taxon which contains beetles which have achieved various degrees of association both with ants and termites. The tergal gland of myrmecophilous aleocharines, which evacuates between the 6th and 7th tergites (Pasteels 1968), constitutes the primary defensive gland utilized by these staphylinids (Jordan 1913). In Lomechusa strumosa (Gravenhorst) the secretion of the tergal gland has been observed to be accurately discharged at aggressive ants which were effectively detered (Jordan 1913). Jordan further noted that ants confined in a tube containing the tergal gland secretion soon died. L. strumosa , a symphile or obligate myrmecophile of Formica santiuinea Latreille, possesses an hypertrophied tergal gland which appears to be more highly developed than those of free-living aleocharines (Pasteels 1968). We report here on the chemistry of the tergal gland secretion of L. strumosa .