Billions Of 17-Year Cicadas Will Emerge; MD Epicenter In 2021

MARYLAND — Summer nights in Maryland will vibrate with the mating calls of 17-year cicadas. The state will find itself at the epicenter of the 2021 emergence of Brood X, or Great Eastern Brood, cicadas.

They only emerge from the ground in large numbers every 17 years, and they make a big impression when they do. The noise in the trees could be deafening from mid-May to mid-June.

Count on billions of these periodical cicadas tuning up in Mid-Atlantic and Midwest states. There are two species of periodical cicadas — the 17-year cicadas, found in northern states, and the 13-year cicadas, found in the South.

Dr. Michael Raupp, known for his Bug Guy blog and a professor emeritus of entomology at the University of Maryland, said parts of Maryland, Virginia and the District of Columbia will witness the spectacle.

"Maryland is at the epicenter of the cicada emergence, so there will be spectacular numbers of cicadas emerging very heavily, starting perhaps in early May," Raupp told WJLA. "But the big ‘cicada-palooza’ is going to happen the last two weeks of May and into early June. So in some areas, there will be 1.5 million cicadas per acre emerging from the ground."

Once they're above ground, the cicadas will head to the tops of trees to mate. Raupp said a cycle of romance, sex, birth and death cicada-style will happen in the trees. It will all start with the male cicadas blasting a loud call to attract mates; once they pair off, the females lay eggs in small tree branches.

The collective song of male cicadas calling for mates can reach up to 100 decibels. Think of a Harley-Davidson motorcycle with straight pipes constantly running outside your window.

The male cicadas are the ones that make all the noise.

They do it by vibrating their tymbals. As described on the Chicago Botanic Garden website, tymbals “are two rigid, drum-like membranes on the undersides of their abdomens.”

Newly adult cicadas are in a rush to mate because they don’t live very long after that — three weeks, maybe four. The females don’t have tymbals and can’t produce the same sounds. They wait quietly to do their job in perpetuating the species, which is to lay as many eggs as possible, up to 600 over their short lifetime.

After mating, the females split the bark on living tree trunks, branches and twigs, burrow in and lay between 24 and 48 eggs at a time.

Raupp said residents should wait until fall — and the disappearance of the cicada swarms — to plant trees in 2021. Dog owners shouldn't let their pets eat too many of the bug's remnants.

You’ll get to bear witness to what is still an unfolding scientific mystery. Scientists can’t entirely explain the synchronized emergence of periodical cicadas, but one evolutionary hypothesis is that the forced developmental delay was an adaptation to climate cooling during the ice ages.