Brace yourself for the inundation of cicadas. As many as 1.5 million of the creatures per acre are due to emerge from the earth very soon. No need to worry about missing their appearance. We’ll hear them a mile away, see them covering foliage, and feel the crunch of their exoskeletons beneath our feet.
There are two main types of the 3,000 cicada species—annual and periodical. Annual cicadas emerge every year in late June or August, while periodical cicadas emerge in cycles of 13 or 17 years, depending on the species. A group of periodicals that emerge at the same time is called a brood. There are 15 different brood cycles. More than one type of brood may emerge simultaneously in the same area depending on their development. The group that we will see this year is known as Periodical Cicada Brood X (10) and rise from the earth when the soil temperature reaches 65 degrees for a depth of 8 inches.
The states gifted with this year’s presence of the insects include Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, North Carolina, New Jersey, New York (extinct or nearly so), Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and Washington D.C.
Brood X cicadas are one to two inches long with a wingspan of three to four inches. They have black bodies, clear wings, and bold red eyes. They breathe through two spiracles on the thorax and eight on the abdomen. Their antennae are short and bristly.
Cicadas are harmless to humans. They may prick our skin if held but do not bite. In fact, people around the world, including Native Americans, once dined on them. They are said to taste like corn and can be grilled, steamed, boiled, or sautéed. Rodents, moles, squirrels, birds, lizards, spiders, killer wasps, snakes, and fish eagerly feast on the delicacies.
Our dogs may nibble on them, as well. However, we should deter them from doing so. Too many cicadas can make dogs sick. The bugs also may be contaminated with pesticides or cause choking in small dogs.
Unlike locus that can result in extensive agricultural damage, cicadas do not harm trees or shrubs. We may notice some leaf loss but not enough to cause lasting damage. According to the Department of Agriculture, molting cicadas eat twigs while adults do not even feed. In addition, their nutrient-rich exoskeleton will enrich the soil and plant growth.
The cicada has the longest life cycle of any insect. They live underground for 17 years while feeding on sap from tree roots. Once mature, they emerge from the ground, lose their exoskeleton, and sprout wings. They then mate, lay eggs in twigs of trees and branches, and die. Eggs hatch in about four weeks and then burrow underground for the next 17 years before repeating the cycle.
The creature’s vast emergence is believed to be a method of survival. So many cicadas arrive at once that predators cannot destroy the entire population. It’s also thought that predator birds tend to have lower density when it’s time for the cicadas to emerge.
Cicadas are among the loudest insects with male mating calls typically ranging from 90 to 100 decibels. That’s louder than a hair dryer or lawn mower but may be as loud as 120 decibels and heard up to one mile away. If you are one who enjoys the music of cicadas, you have three to four weeks to tune in.
Cicada photo credits: Gene Kritsky, Ph.D., Mount St. Joseph University