The Millstone Times

Get Ready Cause Here They Come!!! By Pam Teel

Come May 2021, billions of red eyed cicadas will emerge in New Jersey and a dozen or so other states, after 17 years of being underground. This group of cicadas, known as Brood X, is among the geographically largest of all 17-year periodical cicadas. There are perhaps 3,000 to 4,000 species of cicadas around the world, but the 13- and 17-year periodical cicadas are unique to eastern North America. The cicadas live underground in wingless nymph form, about a foot or two down, feeding on sap from tree roots. That's where they feed for 17 years. Nymphs have strong front legs for digging and excavating cham- bers in close proximity to roots where they feed on xylem sap.

After 17 years underground, sucking sap from tree roots, the cicadas surface en masse. Dime-sized holes will litter the ground where the emerging nymphs crawl up toward daylight. The cicadas’ only defense against predators is to arise together in an enormous swarm, overwhelm- ing the predators’ ability to eat them all. This technique is called predator satiation. As many as 1.5 million cicadas per acre can cover some areas of the east- ern United States. The timing of their appearance varies by location as they wait for the soil to be warm enough. The ideal soil temperature for cicadas is about 64 degrees. For the Mid-Atlantic region, that usually comes by about the third week of May, but it could be sooner. The cicada will stay underground from 2 to 17 years depending on the species. Cicadas are active underground, tunneling, and feeding, and not sleep- ing or hibernating as commonly thought. Then, after the long 2 to 17 years, cicadas emerge from the ground as nymphs. Although cicadas are often called locusts, they are not synonymous. Locusts are short-horned grasshoppers. Cicadas are an entirely different, plant-suck- ing creature. The 13-year cicadas are a mysterious thing. As adults they feed on plant fluids from the young twigs of trees and woody shrubs. For about four to six weeks after the cicadas or above ground, woods and neighborhoods ring with their mating calls, which is loud and buzzing. The males head toward the tops of trees and let out a loud whirring noise that can fill the air at up to 80 to 100 decibels, equal to the intensity of a lawn mower or motorcycle. The cicada sings by contracting the internal tymbal muscles. This causes the membranes to buckle inward, producing a distinct sound. Each species has its own distinctive song that only attracts females of its own kind. After the cicadas mate, each female will lay hundreds of eggs in thin tree branches. Then the adult cicadas will die. When the eggs hatch, new cicada nymphs (cicadas before they’re fully grown) will fall from the trees and burrow back underground, starting the 17-year cycle again. The cicadas won’t hurt you. They don’t sting and they’re not venomous. The ones set to emerge this spring in the United States are harmless to humans and won’t wipe out fields or gardens. The main damage that cicadas inflict on the landscape comes when female cicadas drill holes into slender tree branches, where they then lay their eggs. To protect younger or vulnerable trees, cover them with netting to keep the cicadas away. The whole cycle of emergence, predation, mating, birth and death will take place over the course of about six weeks before the landscape again returns to its former state to await the next emergence in 2038.

48 The Millstone Times

May 2021

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