ARTHROPOD BIOLOGY Nymphs of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae): Aspects of Formation and Transformation

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 subsequently give rise to alates. Temporal production of nymphs in C. formosanus was monitored in monthly collections from four Þeld traps in New Orleans, LA. Nymphs were present throughout the year with peak numbers observed during October/November and May. Large nymphs Þrst occurred in December and peaked in March. Fewer than 1.5% workers formed nymphs within 3 months after collection from the Þeld and after removal of the preexisting nymphs. Collections fromother colonies, kept in the laboratory for 2 yr, 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 factormay 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.