Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 21, 2003
Publication Date: July 6, 2004
Citation: Raina, A.K., Park, Y.I., Lax, A.R. 2004. Defaunation leads to cannibalism in primary reproductives of the Formosan subterranean termite (Coptotermes formosanus). Annals of the Entomological Society of America. 97:753-756. Interpretive Summary: The Formosan subterranean termite is a serious pest of wooden structures and live trees. The winged adults establish new colonies after swarming. The termite is incapable of digesting wood without the microorganisms present in its gut. In the laboratory it was observed that in about 10% of the newly founded colonies, the reproductive adults had eaten their progeny. Such adults were found to be devoid of the gut microorganisms. Loss of these microorganisms in adults, after they had laid eggs for 30 days, was induced with an antibiotic. The treated termites cannibalized their progeny and subsequently died of starvation. Besides being a novel finding, the results provide an insight into the importance of gut microorganisms for the survival of a young termite colony and the possibility of manipulating these for management of termite populations. The information will be beneficial to scientists studying ways to develop alternate technologies for the control of termites.
Technical Abstract: Soon after swarming, the alates of the Formosan subterranean termite, Coptotermes formosanus drop their wings, form tandem pairs and look for new nesting sites to form incipient colonies. Under laboratory conditions, in about 10% of the incipient colonies, the male and the female were found to cannibalize their progeny and then die of starvation. Examination of such adults revealed that all of them had lost most of their gut fauna, essential for the digestion of wood. We used the antibiotic gentamicin to experimentally induce defaunation in 30 day-old adults after they had laid 30-40 eggs. Feeding on 4 ug of gentamicin caused total loss of spirochetes and a significant reduction in the protozoan populations. The progeny of treated adults was significantly reduced after 30 days and almost completely eliminated after 60 days through cannibalism. It is suggested that in the absence of gut fauna the adult termites cannot effectively feed on wood, and the ensuing hunger results in cannibalism of their progeny.