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Texas expecting only annual cicadasTexas News outlets in some parts of the country are abuzz with excitement over the long-anticipated emergence of the periodical year cicada. One of the longest-lived insects, periodical cicadas emerge every 17 years. They are known by what some call their "incessant" buzzing. But in Texas cicada songs will be no louder than most years, according to a Texas Cooperative Extension entomologist. "It is not often Texans get relief from pesky insects, but this is one pest we will miss this summer," said Dr. Mike Merchant of Dallas. "The periodical cicada does not really live in Texas. The closest this species comes is Oklahoma and maybe the edge of the state, along the Red River. "This is one of the problems of our national news network. People hear on television or radio about a serious insect outbreak or new pest somewhere and assume that Texas has the same problem." Texas' annual cicada is also known as the "dog day cicada" because it makes its annual appearance during the dog days of summer. This time of hot, humid weather usually begins in early July and lasts until mid-August. "Dog days" coincide with the time when Sirius, the Dog Star rises at the same time as the sun, Merchant said. The two kinds of cicada have different life spans, Merchant said. The annual dog day cicada emerges every year, has a life span of two to four years, and is a bit larger than the 17-year cicada, he said. "The periodical cicada is easy to identify. It is black with orange eyes, whereas cicadas in Texas are a dark green color. Annual cicadas will be here all summer up until September," Merchant said. The 17-year, or periodical cicada, usually shows up in May and is gone by June, not to be seen or heard from again for 17 years, he said. According to entomologists, this mass emergence is used to ensure some species' survival. A mass emergence increases the chances for mating success and overwhelms predators so they are not able to eat them all, Merchant said. "It is the same principle that fish use when swimming in schools; it is safety in numbers." Remarkable among insects, the periodical cicada spends 17 years as juveniles one to two feet underground, where they feed on tree roots. Temperature clues tell them to dig to the surface. Numerous holes in the ground at the base of trees signal the emergence of both annual and periodical cicadas. After emerging at night, cicadas shed their external skeleton and fly away. The ghostly shells of these cicadas are often seen clinging to trees, fence posts and the sides of buildings, he said. Despite their numbers, cicada nymphs cause little damage to their hosts. Their long development and slow rate of feeding give trees time to recover from any damage, Merchant said the adult periodical cicadas occasionally damage trees by egg-laying behavior. Tips of tree branches may be killed when the female cicada cuts into the wood to insert her eggs. After hatching, the baby cicadas drop to the ground to begin their long adolescence, he explained. Annual cicadas in Texas usually spend only a year or two underground. Texas doesn't have the wild fluctuations in cicada numbers that states to the north and northeast experience, Merchant said. Some people find cicadas' constant buzzing to be annoying. In Texas, trees rarely have more than 100 or so cicadas. But since one cicada can make a sound audible for a quarter-mile, a tree full of cicadas can sound like a whole rhythm band. "Most people will recognize the cicada when it starts singing," said Merchant. "It's kind of like a drill or buzz saw sound in the trees." Date: 5/13/04
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