Necessary Pestilence

Termites, to those of us who are new to the Tucson, Arizona area, we’ve been told (by more people than names we probably remember) are something we homeowners either have, or will have. They are just as much a part of the beautiful landscape of the southwestern desert that drew us as are the coyotes who sing to us at night, and the majestic saguaro that stand continuous guard over us. We are also told of the things that frighten us, rattlesnakes, mountain lions, bears in city parks and packs of Javelinas that will chase you if you are out alone after dark. But these are all things we can see...

No-see-ums , however, and termites are generally a no-see-um, are for many of us more frightening than the big things we can hear (and see) coming – and they can cause considerable damage. There’s just something a little creepy about a critter you rarely see, but that you know can eat your house from down around you. There’s a monthly walk of homeowners here, unknown to those who live outside of the state, but famous here. Homeowners and the people they hire to keep their homes bug free spend copious amounts of time wandering around their homes staring at the foundation, checking for what looks like squiggly straws attached to their homes, one of the dreaded signs of termite trails.

What exactly are these creatures that can cause thousands of dollars worth of damage to our well built homes. Creatures which have caused entire businesses to be built around keeping our homes free of them?

There are over 40 species of termites in 10 genera widely distributed in the Sonoran Desert. Termites are small, white, tan, or black insects that can cause severe destruction to wooden structures. Termites belong an ancient insect group that dates back more than 100 million years. This highly successful group of social insects plays an essential ecological role in the decomposition and recycling of a nutritionally poor, highly resistant, but extremely abundant substance: cellulose. Although many people think termites have only negative impacts, in nature they make many positive contributions to the world's ecosystems. Their greatest contribution is the role they play in recycling wood and plant material. Their tunneling efforts also help to ensure that soils are porous, contain nutrients, and are healthy enough to support plant growth. Termites are very important in the Sahara Desert where their activity helps to reclaim soils damaged by drying heat and wind, and the overgrazing by livestock.

Termites become a problem when they consume structural lumber. Each year thousands of housing units in the United States require treatment for the control of termites. Termites may also damage utility poles and other wooden structures. These pests cause serious damage to wooden structures and posts and may also attack stored food, books, and household furniture.

The ecological importance of Sonoran Desert termites can best be understood by considering the following question: What would happen if we didn’t have termites in our desert? Well, because our aridity severely limits the abundance and distribution of wood decaying fungi, without termites, we would soon be neck deep in cellulose in the form of mesquite and palo verde wood, dead grasses, cactus skeletons and dung. Eventually, few living plants would be left to produce food for animals because there would be no space for new plant seedlings to establish themselves and no nutrients to sustain their growth. All of the space would be taken up by dry, un-recycled cellulose litter, and all of the nutrients would be tied up in this material and thus unavailable for plants in the soil. Without plants fixing carbon-producing food, most animals would disappear. So, without termites, the whole desert ecosystem as we know it would simply collapse.

Tucson area termites partition the Sonora Desert’s cellulose into many ecological niches. For example, one drywood termite, Marginitermes hubbardi, feeds primarily on saguaro skeletons, and another very large primitive drywood termite, Pterotermes occidentis, is a specialist on palo verde wood. Gnathamitermes perplexus, the crust-building subterranean desert termite, feeds on grass, fine dry plant parts and the weathered outer surfaces of woody tissues of all kinds. Heterotermes aureus, the lowland subterranean termite, is an important consumer of native woods on the desert floor, and also of pine.

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