The piercing noises outside has made it known to everyone that cicadas have arrived.

But experts are urging residents not to eliminate the noisy insects that range in size from two to five centimeters.

As cicadas last week began to emerge across communities after 17 years underground, pest control professionals are asked to avoid using broad-spectrum insecticides that could inadvertently kill these insects. According to the National Wildlife Foundation, cicadas pose no threat and are an important food source for many species of birds, mammals, and reptiles and help keep pest insect populations in check naturally.

Cicada experts warn that spraying of insecticides intended for other pests could disrupt this essential ecological process and needlessly endanger beneficial species.

Property owners are advised to simply tolerate the cicadas during their four- to six-week lifecycle above-ground, after which they will disappear until their next emergence in 2038.

Cicadas use their mouth parts to suck on fluids from trees. However, if a cicada makes contact with human skin for an extended period of time, there is a chance it could mistake the skin for a tree part, according to Orkin Pest Control, which serves Will County.

Approximately 17 states from Oklahoma to Wisconsin to North Carolina are seeing trillions of cicadas emerging this year in a rare, double brood event. The two broods have not emerged together in 221 years and are not expected to do so again until 2245. One brood is in the southeast while the other brood is in the Midwest.

Carrie Majors of Shorewood said she is getting used to the noisy cicadas.

“It is bothersome, but they are part of the ecological process,” she said. “It is not like you have to deal with them every summer.”