The Termite Page

The Termite Page

Anthony Curtis, Ph.D.

A Very Brief Introduction to Termites

There are seven families and approximately 2500 species of termites in the order Isoptera worldwide (Waller and La Fage 1987). All are eusocial and colonies are composed of distinct castes which include workers, soldiers, nymphs, and larvae (Krishna 1989). The workers are usually the most abundant caste at any given time of the year (Baroni-Urbani et al. 1978). They are responsible for most of the colony maintenance (i.e., feeding of the dependent castes, foraging, structural maintenance) (Krishna 1989). Soldiers serve to protect the colony from invasion by predators (Krishna 1989). Nymphs are prealate forms which function as reproductive stock for the colony. Larvae are the undifferentiated young of the reproductives, and they usually represent the second largest in colony caste proportion (Howard and Haverty 1981).

The Isoptera are phylogenetically separated into lower termites (Mastotermitidae, Kalotermitidae, Hodotermitidae, Termopsidae, Rhinotermitidae, and Serritermitidae) and the higher termites (Termitidae). Termites are closely related to cockroaches, and they are thought to have evolved from a primitive cockroach-like ancestor approximately 200 million years ago (Krishna 1989).

Termites can also be grouped into four general ecological types (Nutting and Jones 1990) which are based on where they live and the food they consume. The ecological groupings of termites are: dry wood, damp wood, harvester, and subterranean. Dry wood termites are not dependent on the ground for moisture. Their source of water is derived metabolically and they are usually found in posts, stumps, and sometimes buildings made of wood (Krishna 1989). Dampwood termites also do not require soil contact for moisture, but they do require moisture in the wood they consume. They are found in dead, damp, and rotten logs (Krishna 1989). The term harvester is associated with termites that store food products, or harvest fungus which grows in termite galleries. The amount of food stored is reported to vary from one night's forage (Darlington 1982) to stores lasting up to two weeks (Collins 1981). Colonies of subterranean termites must have contact with the soil in order to survive (Krishna 1989). Subterranean termites are by far the most destructive to human carpentry endeavors, costing billions of dollars annually for damage repair and treatment (Su and Scheffrahn 1990). Once the soil nest is established, termites may enter unprotected wooden structures through contact with the soil, cracks in masonry, or by tubes constructed from soil and glandular secretions. Damage to the affected wood may be great, and the structure may crumble or collapse entirely. Termite infestation could mean financial ruin for homeowners. On the other hand, it is a very favorable condition for forest ecosystems because termites are involved in nutrient cycling.

References

Baroni-Urbani, C., G. Josens and G.J. Peakin. 1978. Empirical data and demographic parameters. In: M.V. Brian (ed.) Production Ecology

Collins, N. M. 1981. Consumption of wood by artificially isolated colonies of the fungus-growing termite Macrotrmes bellicosus. Entomol. Exp. Appl. 29: 313- 320.

Darlington, J. P. E. C. 1982. The underground passages and storage pits used in foraging by a mature nest of Macrotermes michaelseni in Kajiado, Kenya. J. Zool. 198: 237-247.

Howard, R. W., and M. I. Haverty. 1980. Reproductives in mature colonies of Reticulitermes flavipes: Abundance, sex-ratio, and association with soldiers. Environ. Entomol. 9: 458-460.

Krishna, K. 1989. Order Isoptera. In: D. J. Borror, C. A. Triplehorn and N.F. Johnson (eds.) An Introduction to the Study of Insects. Saunders College Publishing, Philadelphia, pp 234-241.

Nutting, W.L., and S.C. Jones. 1990. Methods for studying the ecology of subterranean termites. Sociobiology 17: 167-189.

Su, N-Y and R. H. Scheffrahn. 1990. Economically important termites in the United States and their control. Sociobiology 17: 77-94.

Waller, D. A. and J. P. La Fage. 1987. Nutritional ecology of termites. In: F. Slansky, Jr. and J. G. Rodriguez (eds.) The Nutritional Ecology of Insects, Mites, and Spiders. John Wiley and Sons, New York. pp. 487-532.