As spring rolls into summer, homeowners are well-advised to be on the lookout for unwanted house guests -- especially those of the six-legged variety who will literally eat you out of house and home. Termites are likely to be staging their mating flights at this time of year. An unusually large number of winged insects around outdoor lights may be the first indication of a termite population, says Lynn Kimsey, professor of entomology and coordinator of the insect identification hotline at UC Davis. If a quick check around the house and garage reveals small piles of insect wings, it's probably time to call in the professionals. Termites are winged brown insects that resemble ants, except they lack the narrowed waist of an ant. Two species, the subterranean termite and the damp-wood termite, are those that are of concern for homeowners. Most native species take years to establish a colony in a house, however the voracious Formosan termite introduced in Southern California can quickly damage buildings. Kimsey warns that houses built on a former orchard site may inherit an established termite colony that was already infesting old tree roots. "In a way, termites are like cows," says Kimsey. "They both eat materials -- wood and grass -- that they can't digest, but they have microorganisms in their stomachs that take care of the digestion for them." Information on termites and other insects and spiders is available for a nominal fee to the public through the UC Davis insect hotline, (900) 225-BUGS.