They’re Baaaack! Dog-Day Cicada Song Now Fills Our Nights

 developmentally that they are nearly absent as adults in the 12 or 16 years between emergences. When they finally emerge after long juvenile periods, they do so in huge numbers, forming dense aggregations.

According to the NC State Extension, periodical cicadas usually emerge in May, much earlier in the year than annual ones. The drone of their singing can be heard for miles. At the end of the season, the next generation of nymphs moves underground and remains there for either 13 or 17 years. There are 30 broods of periodical cicadas in the eastern US, with broods I-XVII being the 17-year variety and occurring primarily in the Northeast, and broods XVIII-XXX emerging every 13 years and occurring mainly in the South. However, brood ranges overlap, and in our part of the southern Appalachian region, there are both 13- and 17-year cicadas. Populations of the periodic cicada species are synchronized, so that almost all of them mature into adults in the same year. Brood X emerged here in 2021 after hiding silently underground for seventeen years since their last appearance in 2004.

There are no emerging broods here this year of either the 13- or the 17-year variety so, until yesterday, we enjoyed peaceful, quiet nights that allowed Barry to sleep and me to enjoy the heavy, floral-scented night air through the window screens. I thought maybe our unusually cold winter triggered the cicadas’ absence, as well as a marked decrease in other insects, birds, and even squirrels, but I was wrong. I’d just never noticed the annual cicadas because during the years the periodic ones emerge, the cacophony just drowns them out. Last night, Barry closed the widow.

Annual cicadas emerge in July and August, begin singing conspicuously, mate, and start laying eggs about two weeks after emergence. Over the next 30 days, each female can lay 400 to 500 eggs in groups of 10 to 25. Eggs hatch around 1½ to 2½ months later, then the first-instar nymphs fall to the ground and begin feeding on roots under the soil. Fully developed nymphs will emerge two to 10 years later and molt into adults. Adults can be found every year because the population is not developmentally synchronized, so the term ‘annual’ is a bit of a misnomer.

At least 13 species of Neotibicen annual cicadas occur in North Carolina. They are often called Dog Day cicadas because the males sing from mid to late summer. They sing high in trees with long, loud, songs composed of buzzes and clicks. The females are mute and are attracted to the males’ songs. Females jab their eggs into small stems with their saw-like ovipositors. When the tiny cicada nymphs hatch six or seven weeks later, they fall to the soil, burrow, and spend from two up to 10 years feeding on the roots of various plants where they cause no noticeable injury. Cicada nymphs molt four times as they grow.

Each summer, some of the nymphs dig a hole through the soil surface from which they emerge to cling to the bark of trees while they molt into the adult stage. The papery skins of the nymphs are left behind for children to gather up in and bring inside where they are eventually discarded by mothers with no appreciation for cicada nymphal skins.

And that’s today’s Nature Nugget.