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These periodical cicadas known as Brood X appear every 17 years, providing a variety of environmental benefits around Delaware.
If you haven’t spotted a cicada around northern Delaware yet, you likely will in the coming weeks. Or at least you’ll hear their song.
The periodical cicadas known as Brood X have begun their emergence this month. Brian Kunkel, Ornamentals Integrated Pest Management Extension Specialist at the University of Delaware, says he’s already spotted some near his Newark home.
“I can hear them around the house,” he says.
Brood X is a group of periodical cicadas that emerge every 17 years. During their time underground, the critters feed on plant tissue called xylem. The reason for the long amount of time between appearances is a strategy for survival, says Michael Raupp, entomologist and professor emeritus at the University of Maryland.
A variety of animals eat cicadas, including birds, rodents and foxes. By appearing every 17 years, cicadas can outlive the group of animals that have seen them before.
“If you live 17 years, there’s no predator that can track you through time, so you’ve become an untrackable, undependable food resource and you simply outlive your predators,” Raupp explains.
Plus, the plant tissue that cicadas consume underground is a “relatively poor-quality food source,” he says, meaning they need to consume a lot of it over a long period of time to emerge big and strong.
Kunkel says between now and another four to six weeks, the northern Delaware region will see millions of cicadas pop up, another strategy for survival as many will be eaten before they can lay eggs that will continue the species in another 17 years.
Throughout June, the numbers of cicadas will begin to drop off. Raupp predicts Delawareans will see them through mid-June, but by July 4 at the latest, they’ll be gone. Afterward, the annual cicadas we’re used to will appear again, staying from about July to September.
As for the sound cicadas make, it’s all about the mating process. Kunkel says the singing male cicadas do is meant to convince the female to visit them and mate. The sound can reach 100 decibels.
Other than the free concert, Delawareans don’t need to do anything about the visiting insects. Cicadas aren’t harmful to people, kids or pets. Dogs and cats can eat them, but it may be good to prevent them from eating too many at once to avoid sickness, Kunkel suggests.
He says if homeowners have recently planted a young tree and want to avoid limb breakage, or flagging, as the female cicadas lay eggs, they can place insect netting on the tree.
If someone is bothered by the sight or sound of cicadas, Raupp says to become as knowledgeable about the species as possible. If that doesn’t help, speaking to a professional or making a trip downstate or further south where the cicadas won’t be for a few weeks are other options.
As for the overall environmental effects, Raupp says they’re almost endless.
When the cicadas are underground, they take from the plant and then come up and are eaten by a variety of different creatures, providing a delicious and unique meal. Those that aren’t eaten and die naturally will return to the Earth, fertilizing the plants they were eating.
Raupp says for years following periodical cicada emergence, we’ll see not only the creatures who ate them benefitting, but the plants they fertilize will grow stronger and the soil they leave holes in will be aerated, allowing for water infiltration, which is great for trees.
“These guys are little geniuses at transferring materials and energy up and down [the] food webs,” Raupp says.
