Summer is here, and so is the heat and humidity. Soon you might hear a familiar buzzing in the air, similar to an electric saw. If you do, it may be a dogday harvestfly, also known as a dog-day cicada (Neotibicen sp.). The dog-day cicada is a genus of annual cicada, which includes several very similar species. This insect gets its name because it’s seen and heard during the dog days of summer when it’s hot and muggy.
Adults are mostly black with green markings. They have prominent bulging eyes and semitransparent wings held roof-like over their large body. The body size is typically about 2 inches. In Missouri, there are seven species of periodical cicadas, which emerge every 13 or 17 years. They are smaller and emerge in larger numbers.
During the peak of summer from July–August, male dog-day cicadas rest on tree trunks and branches and sing to attract nearby females. The males produce a sound with a high-pitched whine much like an electric saw. This sound comes from two special vibrating membranes in the sides of the abdomen. The buzzing sound lasts for several seconds before fading away. Females do not sing. Depending on the number of cicadas, the sound can be incredibly loud. I remember several years ago when a massive number of periodical cicadas emerged, the sound produced by the thousands of cicadas vibrated the air around me like a drumbeat.
After mating, a female dog-day cicada will insert clusters of eggs into tree branches. In six to seven weeks, small nymphs begin to hatch from the eggs and drop to the ground where they continue to burrow into the soil, seeking tree roots as a food source. Nymphs will continue to feed on the trees and roots, but they are not considered to be plant pests. As they go through several molting processes, they will continue to burrow deeper. Nymphs live underground for three years, and when they are fully developed, they burrow out of the ground at night and climb onto the tree trunk. Adult cicadas emerge from this last stage through a crack along their back, leaving the light brown cast skin behind. Adults live only for five to six weeks, focusing their energy on mating and reproducing.
I’ve seen many shell skins of dog-day cicadas on the ground or on tree trunks, but I never found a live nymph until last summer when I found one still in its shell on a tree trunk. I didn’t have to wait long before the nymph shell began to crack open and within minutes a rather soft, pale-green cicada crawled out of its cast skin and rested until its wings hardened.
The emerging process takes only a couple of minutes, so in order to witness this final phase, you almost have to be at the right place at the right time. But if you happen to find one, it is surely one of the most interesting things to observe in nature. My daughter still talks about this experience every time she hears the cicada sound.
These noisy insects are truly harmless and become an important food source for many other animals that feast on their abundance throughout the summer months. If the flowering dogwood is the first sign of spring, then the sound of a dogday harvestfly is the sign of the peak of a hot summer.
—Story and photograph by Noppadol Paothong
We help people discover nature through our online Field Guide. Visit mdc.mo.gov/field-guide to learn more about Missouri’s plants and animals.
Editor - Angie Daly Morfeld
Art Director - Cliff White
Associate Editor - Bonnie Chasteen
Staff Writer - Heather Feeler
Staff Writer - Kristie Hilgedick
Staff Writer - Joe Jerek
Photographer - Noppadol Paothong
Photographer - David Stonner
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