The emergence of Brood X periodical cicadas last year was a spectacle for all, a nightmare for some, and an entomophile's dream. This year as we settle into the hazy, hot, and humid weeks of summer, the dog days of July and August, another ensemble of cicadas will pay us a subtler and most enjoyable visit. These are the dog day cicadas, members of the genus Tibicen. The dog day cicadas share much biology and behavior with their periodical cousins. The immature stages called nymphs spend years underground feeding on the sap found in the roots of plants. The fully developed nymphs emerge, usually after sunset, and move from the soil to upright structures such as trees and shrubs. The nocturnal emergence is likely a way to avoid detection by day-hunting predators such as birds and squirrels. The nymphs hold fast to the plant and their exoskeleton splits along the midline to allow the adult cicada to emerge. Newly emerged adults are light in color with faint shades of green and tan. After several hours, their exoskeleton darkens and hardens and by sunrise the dog day cicadas are ready to fly. Once in the treetops the males vibrate a drum-like membrane called a tymbal to create their shrill song. The song is unique for each species of cicada and the female uses the chorus to locate and select a worthy mate. After mating, the female cicada inserts tiny eggs into small branches of trees. After a month or so eggs hatch and the nymphs dive to the ground and burrow into the soil to feed on the roots of trees and shrubs. The dog day cicadas belong to a group known as the annual cicadas. Annual does not mean that they spend only a year underground as nymphs. The term annual refers to the fact that these cicadas are seen every year. Dog day cicadas require several years to develop. The annual visit contrasts with the massive synchronous appearance of the periodical cicadas that occur in specific geographic locations at intervals of 13 and 17 years. Another interesting difference between periodical and annual cicadas is their strategy for survival. Periodical cicadas rely on strength in numbers to overwhelm the capacity of predators to consume them. The emergence of huge numbers of periodical cicadas allows hungry predators to eat their fill, yet enough cicadas remain to successfully reproduce and carry on. The dog day cicadas rely on stealth and speed. It is unlikely that you will see, capture, or photograph a healthy dog day cicada in a treetop. Their green and black coloration creates camouflage enabling them to blend into their arboreal environment. They have excellent eyesight and can fly like F-14's. They are hard to spot and when they see you approach, they rapidly fly away. Your best bet for getting up close and personal with a dog day cicada may be to wait until nightfall, grab a flashlight, head for your favorite cicada tree, and watch for the nymphs to arise from their subterranean crypts. The dog days are here. Why not sit back with a cool drink and enjoy the chorus?

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