Chemical Defense in Carabids and Its Bearing on Phylogeny

Abstract

The existence of chemically based defensive mechanisms in Carabidae has been known for many years, and reasonably detailed descriptions of the secretory systems and associated twin pygidial reservoirs were published at the turn of the century (e.g., Dierckx, 1899, 1901). Likewise it was early recognized that several widely differing groups of chemicals were implicated, but the limited sensitivity of analytical methods of the time precluded their firm identification. However, some rather wild guesses were made on the basis of odor or other uncritical data and the original publications were subsequently quoted and requoted in the major physiological treatises, assuming an air of ever increasing (but quite unjustified) authenticity in the process. Thus claims that Carabus spp. relied on butyric acid (Marchai, 1910); that Brachinus spp. (Fredericq, 1910) and Pheropsophus spp. (Vialli, 1939) utilized oxides of nitrogen; and “Paussidae”, iodine (Fredericq, 1910), have stood until comparatively recent times, although all are now known to be well wide of the mark.