CHEMICAL DEFENSE OF GIANT SPRINGTAIL TETRODONTOPHORA-BIELANENSIS (WAGA) (INSECTA, COLLEMBOLA)

The giant springtail, Tetrodontophora bielanensis (Waga), is character ized by integumental openings (pseudocells) from which small droplets of a sticky defensive fluid are secreted after molestation. The secret ion originates initially from secretory cells below the pseudocellae; subsequent irritations result in release of hemolymph, which was ident ified by both chemical and microscopical methods as well as by scannin g electron microscopy. Bioassays with topically treated ground beetles Nebria brevicollis showed that the pseudocellular quid evokes a total disorientation and cleansing behavior of the beetle. The main constit uents were identified as the following pyrido-pyrazines: 2.3-dimethoxp yrido[2.3-b]pyrazine (1), 3-isopropyl-2-methoxy pyrido[2,3-b] pyrazine (2), and 2-methoxy-4H-pyrido[2,3-b]pyrazine-3-one (3). These alkaloid s are mainly present in the pseudocellar quids of female and male spri ngtails but are absent in their food or feces. Minor amounts are found in the hemolymph of adults, while larvae contain traces of 2 only. Al l compounds were synthesized and tested for activity. In natural conce ntrations, the synthetic alkaloids elicited the same effects from the ground beetles as the pseudocellar fluid.