17- year cicadas are expected by everyone.
(Mirror Daily, United States) – Latest statistics have shown that throughout most of the eastern Ohio, western Pennsylvania and West Virginia cicadas might emerge from the grounds.
The last emergence was in 1999, precisely 17 years ago. Cicadas are known to spend most of their lives underground. They have a life span of 4 to 17 years and are divided into three species. However, few other species take 13 years to complete their life cycle.
People are more familiar with the green dog-day cicadas that appear every summer and take only 4 years to grow. However, the 17-year cicada is a different story. Still, they can sometimes be seen more often that once in 17 years, because there are different broods with various schedules depending on the area.
For instance, Brood V is presently emerging in Ohio and West Virginia. Precisely 12 broods of 17-year cicadas, each one of them identified by Roman numerals. They will emerge throughout Northeast and Midwest. However, each brood has a different year of maturing.
According to the statistics, it means that there are 5 years out of every 17 when no 17-year cicadas emerge from the ground. Dog day cicadas have a black appearance with greenish marking, reach two inches long and have two pairs of strongly veined membranous wings.
On the other hand, periodical cicadas have bright red eyes, wing veins, black and smaller bodies. During the immature stage, periodical cicadas live by feeding with fluids from the roots of various types of trees. A few weeks left before emerging, nymphs start digging exit tunnels close to the surface of the soil.
Most of them emerge after a few days, and no scientist managed to predict the exact moment. Just after emerging, cicadas are soft, moist and white. Their body gets dark and hard as they dry. Adults need from three to five days to completely mature. That is when they start singing to attract females.
The music of the male cicadas is produced by tympals, a sound-producing unique feature. It consists of ridged membranes situated on the first abdominal segment. Thanks to a hollow resonating chamber beneath the membrane, the male is capable of singing.
Females lay 20 eggs in each slit after mating and a total of 600 eggs. After this process ends, all adult cicadas die. After six weeks, the eggs hatch and the tiny nymphs will try to find a root which will help them survive. A new brood of cicadas will emerge after 4, 13 or 17 years.
Image Source:Wikipedia