This month we begin a four part series answering questions about termites. Part 1 deals with Arizona termite biology. Our thanks to Dr. Robert Smith, Department of Entomology, University of Arizona for this information.

Question: What is the ecological role of termites in Arizona? What are termites good for?

Answer: Termites serve an essential role in recycling the nutrients contained in cellulose, a very resistant material that is the structural component in wood and other plant materials. Termites are especially important in regions of our state because fungi cannot help in cellulose recycling when it is extremely dry. If it weren't for termites, we would soon be buried in cactus skeletons and other woody desert plant material.

Question: Are there different kinds of termites in Arizona?

Answer: Yes, there are about twenty different species of termites in Arizona, but only about five or six of these species cause damage to structures.

Question: What is a termite colony?

Answer: An insect colony is a social system consisting of many related individuals working efficiently together. Termite colonies consist of a king and queen that do most if not all of the reproduction, workers that forage for food and keep the colony clean, and soldiers that protect the colony against enemies, especially ants. At certain times of the year the colony also produces alates, winged individuals of both sexes that disperse from the colony, mate, and attempt to establish new colonies.

Question: What are the kinds of termites that cause damage to structures in Arizona?

Answer: In general there are three categories. These are the subterranean termites, the dampwood termites, and the drywood termites.

Question: Are termites a problem in all areas of the state?

Answer: All wooden parts of structures in localities below 8000 ft. elevation are subject to damage by subterranean termites. Drywoods occur below 6000 ft. elevation.

Question: Where do termites live?

Answer: Subterranean termites have colonies deep in the soil whereas drywood termites always live in the wood they infest. Dampwoods can live in the soil or in wood that is constantly moist.

Question: We had Formosan termites in Florida. Do they occur in Arizona?

Answer: Happily, these very aggressive, introduced termites do not occur in Arizona, and it is doubtful that they will ever become established in our state because Arizona is too dry for them.

Question: Why do subterranean termite colonies live in the soil?

Answer: The colony needs the perennial moisture provided deep in the soil; without access to this soil moisture the colony will die.

Question: How many termites are there in a single colony?

Answer: There can be millions of individual termites in a single subterranean colony! Drywood and dampwood colonies contain from a few hundred to a few thousand individuals.

Question: How can I distinguish between termites and ants?

Answer: Termite workers are whitish and soft bodied with dark heads. Ants on the other hand are hard bodied and dark in color. Termites have straight antenna and ants have "elbowed" antenna. The termite abdomen is broadly joined to the thorax whereas the ant abdomen is constricted at the juncture of the thorax with the abdomen.

Question: I sometimes see crusts of mud covering fence posts, the bottoms of saguaro cactus, and dead grass tufts in my backyard. When I break the crust there are termites inside. Does this mean my house is threatened by termites?

Answer: This is the work of the "Crust Building Sub" termite. It is an ecologically important arid lands termite that poses no threat to structures whatsoever. These termites eat only grass and the weathered wood on the exterior of posts or the trunks of trees and cactus. They never enter structurally sound wood. Disreputable pest control marketers often use the presence of Crust Building Subs to alarm homeowners and to purchase unneeded services.

Question: Something killed my pyracantha bush by cutting it off at ground level. What is responsible for this damage?

Answer: The damage was probably caused by the "Desert Dampwood" termite which is the only species in Arizona that can feed on green wood. This termite also sometimes feeds on young citrus trees.

Question: How do termite colonies get started?

Answer: Once or several times each year, some members of the colony develop wings. These individuals are male and female reproductives. The reproductive individuals depart their parent colony and fly off to mate with reproductives from other colonies. When a male reproductive meets a female reproductive, he follows her until she finds a place suitable for attempting to establish a new colony. The pair then excavate a cavity in wood or soil, break off their wings, and mate. The female then lays a few eggs and both male and female feed the young nymphs when they hatch.

Question: Do termites have any natural enemies?

Answer: Absolutely! Birds, bats, frogs, toads, lizards, rodents, mites, and ants love to eat termites. Predation on winged reproductive termites is tremendous, and the probability of new colony establishment is very low. Nematodes (tiny worms) and some fungi may infest and injure termite colonies.

Question: If I see flying termites in my house does it mean my house is infested with termites?

Answer: Millions of winged termites fly each year and termites like other insects often come to lights, so a few winged termites around lights does not indicate an infestation. However, if there are numerous winged termites on indoor window sills, it may indicate that they are emerging from infested wood inside the house. Save the termites (and wings) in rubbing alcohol for identification.

Question: We never had termites back in Maine (Minnesota) - why is that?

Answer: Termites have a tropical center of distribution and cannot survive in soil that is deeply frozen for part or most of the year.

Question: Are all areas equally likely to have subterranean termites in the soil?

Answer: It is safe to say that every house built below 8000 feet is in the foraging range of a subterranean termite colony. Flood plains and areas close to drainages usually have more subterranean termite colonies than rocky uplands. Mesquite bosques are especially loaded with subterranean termites.

Next month Dr. Smith will answer questions about termite structural damage in Arizona.