The Termite Page
Anthony Curtis, Ph.D.

Termite Video (dissection microscope)

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 the biogeochemical cycling (nutrient cycling) of carbon and nitrogen.

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 Macrotermes 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.

Termites and Forest Ecosystems

Nitrogenous products of termite origin may enter and be distributed within the ecosystem in several ways. Adult termites are able to pass nitrogen-containing compounds to their young by trophallaxis. This transfer can occur from stomodeal food, proctodeal food, and salivary secretions (Waller and La Fage 1987). Stomodeal food is food that is partially digested in the crop of the donating termite which is regurgitated and fed to a recipient termite. The dependent castes receive nutrients and digestive enzymes in the process. Although this behavior is not common among termites (La Fage and Nutting 1978), it represents a possible mode of distribution of nitrogen containing compounds to colony members. Proctodeal food is transferred from the anus of donor termites. This food is also partially digested and differs from feces (Waller and La Fage 1987). Flagellate protozoans and other gut symbionts are transferred along with proctodeal food. Saliva is rich in lipids and protein (La Fage and Nutting 1978) and is also fed to dependent castes (Waller and La Fage 1987).

Another way in which nitrogen may enter the ecosystem is through direct deposition onto soil. Salivary secretions mixed with soil and wood particles are used by termites to build tunnels and galleries. Most termite nests are made of carton which is composed of soil mixed with termite feces. These galleries, tunnels, and carton can extend far into the soil, and this close association to the soil offers opportunity for the nitrogenous compounds to adsorb to soil components (Wood and Sands 1978).

Finally, further N-distribution into the ecosystem by termites may occur through the seasonal dispersion during reproductive flights of winged adults called alates. Species differ as to the time of dispersal and number of dispersal events. In general, alates develop from workers or nymphs. At the appropriate time they fly away from the colony, form mating pairs, and generate new colonies far from the original nest site (Nutting 1969). Most alates fall victim to predation and other environmental factors. In this way, their complement of nitrogen is recycled in the form of food and detrital material (DeAngelis 1992).

DeAngelis, D. L. 1992. Nutrient interactions of detritus and decomposers. In: M. B. Usher, M.L. Rosenzweig and Kitching, R.L. (eds.) Dynamics of Nutrient Cycling and Food Webs. Chapman and Hall, London. pp.123-141.

La Fage, J. P. and W. L. Nutting. 1978. Nutrient dynamics of termites. In: M. V. Brian (ed.) Production Ecology of Ants and Termites. Cambridge Univ. Press, U.K., pp. 165-232.

Nutting, W.L. 1969. Flight and colony foundation. In: K. Krishna and F.M. Weesner (eds.), Biology of Termites, Vol. 1, Academic Press, New York, pp. 233-282.

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.

Wood, T. G., and W. A. Sands. 1978. The role of termites in ecosystems. In: M. V. Brian (ed.) Production Ecology of Ants and Termites. Cambridge Univ. Press, U.K., pp. 245-292.

Termites and Biogeochemical Cycling

In addition to being an economically important pest, termites are also important ecologically to forest ecosystems. They are closely linked with biogeochemical (nutrient) cycling. The major biogeochemical cycles are: hydrologic, carbon, oxygen, nitrogen, sulfur, and phosphorus (Staley and Orians 1992). Components of each conceptually belong to "reservoir pools." Depending on the scale, reservoir pools may include all or part of the atmosphere, the ocean, the sediments, and living organisms. In general, flux between reservoirs is dominated by the biota and their activities. Elements are exchanged slowly between some reservoirs over a long period of geological time (Rodhe 1992).

Termites are important in the carbon cycle through their roles as consumers and detritivores (DeAngelis 1992). The termite gut is host to protozoan and bacterial symbionts that are able to digest wood cellulose and thus release the energy otherwise unavailable to the insects (Waller and La Fage 1987). Termite foraging and tunneling redistributes soil and increases the surface area available to bacteria and fungi (Wood and Sands 1978). The breakdown of lignin and cellulose found in wood is primarily facilitated by the enzymatic secretions of fungi (Bold et al. 1980). Fungi are also able to liberate various elements such as nitrogen, phosphorus, potassium, sulfur, iron, calcium, magnesium, and zinc (Bold et al. 1980). The ability of termites to influence the physical structure and chemical nature of their environment impacts vegetation and other components of the ecosystem (Wood and Sands 1978). Their effect on the nitrogen cycle has traditionally been recognized as returning nutrients to the ecosystem. However, recent studies indicate that termites may play a larger role in the cycling of nitrogen than was once thought.

The atmosphere is composed of 78% nitrogen as N₂ gas. This represents a reservoir pool for nitrogen in terrestrial ecosystems. Biota cannot use this element until it is "fixed" into useable forms. Nitrogen fixation most commonly occurs in two ways: lightning accounts for the fixation of 10% of global available nitrogen and the other 90% of fixed nitrogen is generated from the action of microbes. Free living bacteria, cyanobacteria, and symbiotic bacteria in nodules in the low O₂ environment within leguminous plants all involved in microbial nitrogen fixation (Jaffe 1992). However, there is another place where nitrogen fixation occurs.

The microbial gut flora of termites include nitrogen fixing bacteria (Benemann 1973, Breznak et al. 1973, French et al. 1976, Potrikus and Breznak 1977, Prestwich and Bentley 1981). The rate at which nitrogen is fixed varies among termite species (Prestwich et al. 1980, Breznak 1984, Bentley 1987, Waller et al. 1989) and within species as a function of food quality (Breznak et al. 1973), termite caste (Prestwich et al. 1980, Hewitt et al. 1987), and termite size (Waller et al. 1989). Intraspecific variation may also exist due to seasonal factors (Pandey et al. 1992, Waller et al. 1989). Newly fixed nitrogen is incorporated into termite tissue, excretion products, and secretion products (Bentley 1984).

Benemann, J. R. 1973. Nitrogen fixation in termites. Science 181: 164-165.

Bentley, B. L. 1984. Nitrogen fixation in termites: Fate of Newly fixed nitrogen. J. Insect Physiol. 30: 653-655.

Bentley, B. L. 1987. Nitrogen fixation by Nasutitermes and Velocitermes in Venezuela. In: Eder, J. and Remhold, H. (eds.), Chemistry and Biology of Social Insects. Verlag J. Peperny, Munich, p. 365.

Bold, H. C., C. J. Alexopoulos and T. Delevoryas. 1980. Morphology of Plants and Fungi. Harper and Row, New York. pp. 610-612.

Breznak, J. A. 1984. Biochemical aspects of symbiosis between termites and their intestinal microbiota. In: Anderson, J.M., Rayner, A.D.M., and D.W.H. Walton, (eds.) Invertebrate-Microbial Interactions. Cambridge Univ. Press, Cambridge, U.K. pp.173-203.

Breznak, J. A., W. J. Brill, J. W. Mertins and H. C. Coppel. 1973. Nitrogen fixation in termites. Nature 244: 577-580.

DeAngelis, D. L. 1992. Nutrient interactions of detritus and decomposers. In: M. B. Usher, M.L. Rosenzweig and Kitching, R.L. (eds.) Dynamics of Nutrient Cycling and Food Webs. Chapman and Hall, London. pp.123-141.

French, J. R. J., G. L. Turner and J. F. Bradbury. 1976. Nitrogen fixation by bacteria from the hindgut of termites. J. Gen. Microbiol 95: 202-206.

Hewitt, P. H., M. C. Van der Westhuizen, T. C. De K. Van der Linde and R. A. Adam. 1987. Acetylene reduction by the harvester termite Hodotermes mossambicus (Hagen). J. Entomol. Soc. S. Africa 50: 513-520.

Jaffe, D. A. 1992. The nitrogen cycle. In: S. S. Butcher, R.J. Charlson, Orians, G.H. and G.V. Wolfe (eds.) Global Biogeochemical Cycles. Academic Press Ltd. London. pp. 263-284.

Pandey, S., D.A. Waller and A.S. Gordon. 1992. Variation in acetylene-reduction (nitrogen-fixation) rates in Reticulitermes spp. (Isoptera: Rhinotermitidae). Virginia J. Sci. 43: 333-338.

Potrikus, C. J., and J. A. Breznak. 1977. Nitrogen-fixing Enterobacter agglomerans isolated from guts of wood-eating termites. Appl. Envir. Microbiol. 33: 392- 399.

Prestwich, G. D. and B. L. Bentley, 1981. Nitrogen fixation in intact colonies of the termite Nasutitermes corniger. Oecologia 49: 249-251.

Prestwich, G. D., B.L. Bentley and E. J. Carpenter. 1980. Nitrogen sources for neotropical nauste termites: Fixation and selective foraging. Oecologia 46: 397- 401.

Rodhe, H. 1992. Modeling biogeochemical cycles. In: S. S. Butcher, R.J. Charlson, Orians, G.H. and G.V. Wolfe (eds.) Global Biogeochemical Cycles. Academic Press Ltd. London. pp. 55-72.

Staley, J. T. and G. H. Orians. 1992. Evolution of the biosphere. In: Butcher, S.S., R.J. Charlson, Orians, G.H. and G.V. Wolfe (eds.) Global Biogeochemical Cycles. Academic Press Ltd. London. pp 21-54.

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.

Waller, D. A., G. A. Breitenbeck and J. P. La Fage. 1989. Variation in acetylene reduction by Coptotermes formosanus (Isoptera: Rhinotermitidae) related to colony source and termite size. Sociobiology 16: 191-196.

Wood, T. G., and W. A. Sands. 1978. The role of termites in ecosystems. In: M. V. Brian (ed.) Production Ecology of Ants and Termites. Cambridge Univ. Press, U.K., pp. 245-292.

Selected publications:

Waller, D.A. and A.D. Curtis. 2003. Effects of sugar-treated foods on preference and nitrogen-fixation rates in Reticulitermes flavipes (Kollar) and R. virginicus (Banks) (Isoptera: Rhinotermtidae). Annals of the Entomological Society of America 96: 81-85.

 Morlino, S.E., Curtis, A.D. and D.A. Waller. 2001. Effects of salt-treated wood on feeding and survivorship in subterranean termites (Rhinotermtidae: Reticulitermes) from coastal and inland forests. Sociobiology 38: 753-764.

Curtis, A. D. and D. A. Waller. 1998. Seasonal patterns of nitrogen fixation in termites (Isoptera: Rhinotermitidae) Functional Ecology, 12: 803-807.

Curtis, A. D. and D. A. Waller. 1997. Problems with the interpretation of mark-release- recapture data in subterranean termites (Isoptera: Rhinotermitidae). Sociobiology, 30: 233-241.

Curtis, A. D. and D. A. Waller. 1997. Variation in nitrogen fixation rates in termites (Isoptera: Rhinotermitidae): response to field and laboratory dietary nitrogen. Physiological Entomology, 22: 303-309.

Curtis, A. D. and D. A. Waller. 1996. The effects of decreased pO₂ and increased pCO₂ on nitrogen fixation rates in termites (Isoptera: Rhinotermitidae). Journal of Insect Physiology, 42: 867-872.

Curtis, A. D. and D. A. Waller. 1995. Changes in nitrogen fixation rates in termites (Isoptera: Rhinotermitidae) maintained in the laboratory. Annals of the Entomological Society of  America, 88: 764-767.

Other Termite Links

Dr. Don's Termite Pages

University of Nebraska Cooperative Extension

On-Line Catalog of the Living Termites of the New World (From The International Union for the Study of Social Insects)

Termites of North America

 Thanks for your interest in termites and for visiting The Termite Page.
Please send your questions, comments, or suggestions to acurtis@thetermitepage.com.

Copyright ŠAnthony Curtis, Ph.D. 1996-2010. All Rights Reserved. Do not duplicate without permission.