Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2004
Publication Date: 7/6/2004
Citation: Raina, A.K., Osbrink, W.L., Park, Y.I. 2004. Nymphs of the Formosan subterranean termite (Isoptera: Rhinotermitidae): aspects of formation and transformation. Annals of the Entomological Society of America. 97:757-764. Interpretive Summary: Formosan subterranean termite is a very serious urban pest infesting houses and live trees in several states of the US and in Hawaii. Mature colonies having several million individuals produce nymphs with wing buds, a caste that gives rise to winged adults forming huge swarms. It is these winged adults that form new colonies. Nothing is known about how the nymph formation is induced and what factors lead to their transformation into adults. These developmental processes take place in colonies with a mature queen but not in a laboratory setting. While formation of the nymphs and their transformation is described in detail, we have only been able to speculate about the presence of a nymph induction factor. This information, in addition to providing a better understanding of the dynamics of a termite colony, will stimulate research to elucidate the nymph induction factor.
Technical Abstract: Mature colonies of the Formosan subterranean termite Coptotermes formosanus Shiraki, like most other termite species produce a reproductive caste in the form of nymphs that give rise to alates. Temporal production of nymphs in C. formosanus was monitored in monthly collections from four field traps in New Orleans, LA. Nymphs were present throughout the year with peak numbers observed during October/November and May. Large nymphs first appeared in December and peaked in March. Fewer than 1.5% workers formed nymphs, within three months after collection from the field and, after removal of the preexisting nymphs. Collections from other colonies, kept in the laboratory for over two years, did not produce any nymphs. It is speculated that a nymph induction factor (NIF), possibly coming from a mature physogastric queen, elicits nymph formation. The same or a similar factor may also be responsible for further development of nymphs and their transformation to alates. In the absence of this latter factor, the nymphs, except those in the most advanced stage of development, are either cannibalized or transform into brachypteroid neotenics. A scheme for the formation and transformation of various developmental stages within each caste of C. formosanus is presented.