Spring in Milwaukee brings the onset of return arrivals of many avian friends. Warblers, Orioles, and most famously the American Robin. Sounds of courtship, challenges of mating, nest building and sweet sounds of the little ones with excitement that someone has come to feed them.
Summer in Milwaukee, this year, has brought the drip, drip, drip of rain drops, the buzz of mosquitos in major masses, humming of bees and an abundant amount of fluttering butterfly wings. As the rain slows down and July comes to an end, there is a noticeable decrease in avian activity throughout the backyards. The songs of many birds have lessened up only to be replaced during the heat of the day by the cicadas (sometimes referred to as locusts although they are not true locusts and not even related to them.) Locusts are a type of grasshopper. Cicadas are related to the leafhopper and spittlebug family.
It is the male cicadas that sing their high pitched, buzz like song. Each species has its own sound. Each male has different songs whether it be for courtship or even a call of distress. The distinct sound of each species allows them to attract females of only their species. The song of some cicadas, being the loudest of all insect-produced sounds, is so high pitched that it can actually do permanent damage to the human ear if sung immediately at the site of the human ear. Crickets make their sound by rubbing their legs together. Cicadas have drum-skin like organs at the base of its abdomen and it is these organs that vibrate to make their song. Although the female also has these organs, they do not vibrate with song.
Although the most common genus of cicadas in North America are the ‘dog-day’ cicadas, an annual genus, the best known genus is the Magicicada (periodical cicada), known for its extremely long life cycle of 13 to 17 years. Thirteen years is the most common in our mid-west, Milwaukee area. This life cycle consists of the entire process of growing from egg to nymph to adult with the longest stage being the nymph stage. An adult cicada lives on the average only two to four weeks.
Female cicadas cut slits in small branches of host trees and shrubs and lay eggs. There are normally several sites in which they lay eggs. This procedure may kill off the small branch in which the eggs have been layed but has not been noted to do any major damage to older trees. Once hatched, the nypmphs drop to the ground and burrow into the root area of the tree where they feed and grow for two to sixteen years (depending on whether they are annual or periodical) at which time they dig out of the ground to molt and become adults.
The emergence of the nymphs for the Magicicada genus is synchronized in such a way that many will emerge at one time, normally during the night hours. This emergence is at its highest peak normally mid-June through mid-July. Once emerged they will find tree and shrub branches on which they attach and molt their skin into adults. For this reason, many times one can find many ‘skins’ hanging together in one area. North American cicada species are generally one to two inches long, have two eyes widely spread on two sides of the head area and the wings are transparent. Cicadas also have three small eyes located between the two larger eyes and of the same color as the larger eyes. The wings of the magicicada genus have orange veins and the eyes are reddish-orange.
If this Magicicada genus emerges only once every thirteen to seventeen years, then why in many areas around Milwaukee do we hear their song every summer, some years more than others? The most common cicada, as stated above, is the dog-day cicada which is a more annual genus with life cycles of two to five years. Their emergence is not synchronized as the Magicicada is and, therefore, there will be some emergences each year. The annual dog-day cicada emerge during July and August. They have green bodies with black markings and their wings have green veins.
The last noted emergence of this genus in the Milwaukee area was noted to have been during 2007. This would put the next possible emergence to be somewhere between 2020 and 2024.
Did you know that some nationalities consider this cicada a delicacy; the female in particular as it has more meat?
Sources of information include Wikipedia and the Wisconsin DNR.