The mating calls of the males are a constant drone during the warm daylight hours, being loud enough in some areas to be a real nuisance to those with sensitive ears. For once I'm almost glad to be a bit hard of hearing. Oddly, the sound is produced by vibrating a membrane on the side of the abdomen, somewhat like the skin on the surface of a drum. The male abdomen is hollow, amplifying the sound. Females do not make any sound, but apparently find the males' calling irresistable, flying quickly to join their chosen mate..
Our first warning that something unusual was happening actually came with the numerous shed exoskeletons (shells) of the nymphs (larval form) attached to bushes, tree trunks, and even walls. In some areas these were almost a solid carpet on the ground. Along with these shells there were holes in the ground which looked as if someone had made them with a stick. These, we soon learned were made by the nymphs as they climbed to the surface after their seventeen year life underground feeding on sap sucked from plant roots.One lady told me today that she had collected fifteen gallons of nymph shells on her property !
These cicadas are often called "seventeen year locusts", which is a misnomer, since they are not related to locusts, which are actually a kind of grasshopper. The cicada, in its adult form does not eat the vegetation it perches on, The females may damage young trees by their egg laying activity, as they cut holes in the bark of tender twigs to lay their eggs. As soon as they hatch, the young nymphs drop to the ground and burrow down to spend the next part of their lives underground
Not all cicadas have a seventeen year life cycle. Another brood is due to emerge in this area next year, which is on a thirteen year cycle. Other cicadas are not "periodical", but are "annual" cicadas, emerging every year in late summer. These do not arrive in such large numbers so their arrival is less dramatic. Their singing is generally just an expected background to hot summer days, rising louder and faster as the temperature rises.
Meanwhile, we'll be seeing dead cicadas around here for a while, since they only live for two to four weeks. Having mated and laid eggs, they will simply die if they haven't already become part of nature's food chain. Birds, and many small animals relish them. In some parts of the world they are also eaten by humans. While they don't exactly look delectable to me, I must admit that shrimp, lobsters and crabs look pretty scary to me until properly prepared for eating !
If you care to probe more deeply into the subject of cicadas, I recommend the following link on the Virginia Tech website http://pubs.ext.vt.edu/444/444-276/444-276.html
And, a final word from the Creator of all. "He has made everything beautiful in its time." Eccl. 3:11 This is definitely the time of the cicada in Bedford.