Billions of bugs will soon invade Northwest Indiana.

“This year is the first time in 221 years … that both 13-year brood and 17-year brood [cicadas] are going to be synching up,” said Johnathan Rowe, naturalist at PNW’s Gabis Arboretum. “Two major broods … are going to be emerging at the same time, which means double the number of cicadas there were 17 years ago.”

The last time the area saw two cicada groups emerge concurrently – a phenomenon scientists call a “dual emergence” – was 1803. A University of Illinois study estimates that 1.5 million cicadas will emerge per acre this year.  

“It’s going to be difficult to avoid cicadas, and they’re going to be everywhere,” Rowe said. 

“Cicadas…don’t harm things, but very much … can if you have a young tree,” he said. “They’re going to be looking for mates, once they find a mate they’re going to be laying their eggs in tree branches.”

They lay those eggs in slits they make in small twigs. Heavily damaged twigs and branches may break off. Cicadas target young oak, maple, redbud and hawthorn trees. They will not attack mature trees.

“The way you can protect trees… is to put netting around [them],” he said. “Something like that would be fine enough to where the cicadas wouldn’t be able to get through.”

Though the swarms of cicadas can be noisy when they chorus, or produce a clicking sound to attract females to mate, Rowe said the bugs are completely harmless to people and pets. 

“The cicadas that have emerged this year… that are 13 years old and 17 years old,” he said. “After they have reproduced, they’re going to die.”

Male cicadas will die after mating. Females normally lay 500 eggs on tree branches before dying. 

“Cicadas will come out of the ground, then they’re going to climb onto a tree… or some vertical structure,” he said. “Then, they’re going to molt and shed from they’re nymph stage to adult stage.”

The rest of a cicada’s life is spent underground as a nymph consuming fluid sucked from plant roots. 

But don’t imagine that cicadas have it easy living below and above ground.  Once they emerge, the bugs are prey for squirrels, rabbits, cats, dogs and other animals that find cicadas to be an easy, though crunchy, source of protein. 

“It’s a feeding frenzy… for all of the animals,” said Rowe. “They’re going to enjoy it.”