Do Cicadas Bite or Sting? Are Cicadas Harmful to People?

Can a cicada bite you?

A cicada has no jaws. Its mouthparts are folded into a long, sharp beak, called a rostrum, that lies under the body between the front legs. Inside are fine needle-like stylets that the insect pushes into roots or twigs to reach the xylem, the plant tissue that carries water and dissolved minerals.

Because the beak is made to pierce wood and bark, it can poke through human skin if a cicada mistakes an arm or a leg for a branch. This happens mostly when someone handles a cicada or lets one sit on the skin for a while during a mass emergence. It feels like a small, sharp prick, and since cicadas feed only on plant sap, there is nothing for them to take from you and nothing harmful to leave behind.

Cicadas are not aggressive. They do not attack people or defend territories, and they land on people simply because a standing person looks much like a tree trunk to a clumsy flier.

Do cicadas sting?

No cicada has a stinger. The spike that people sometimes notice at the tip of a female’s abdomen is an ovipositor, a saw-edged blade used to cut slits in twigs and lay eggs inside, about 20 eggs per slit in periodical cicadas. It has no venom gland, and males do not have one at all.

The idea that cicadas sting is old. A report published by the Royal Society in London in 1666 described insects in New England with a “kind of taile or sting” that they struck into trees and poisoned them. The writer was describing female periodical cicadas laying eggs, which harms twigs but not people.

Are cicadas poisonous or venomous?

Cicadas are neither venomous nor poisonous. They inject nothing when they probe, and their bodies contain no toxins. Many birds, mammals, reptiles and fish eat them in huge numbers without ill effect, and in many cultures, including among some Native American peoples in the past, cicadas have been cooked and eaten by people too.

There is also no evidence that cicadas carry or transmit diseases to humans. Unlike mosquitoes, ticks or biting flies, they never feed on blood.

Can cicadas damage trees and gardens?

Cicadas can harm young trees, but only in a limited way. When a female cuts egg slits in a pencil-thin twig, the twig may split and the leaves beyond it wilt and turn brown, a condition called flagging. During a large periodical cicada emergence, whole tree crowns can look scorched with dead twig tips. Mature trees usually recover, acting as if they had been lightly pruned, but newly planted saplings can be badly weakened.

Underground, the nymphs feed on roots for years. Their feeding can slightly slow tree growth, especially in the year before an emergence, but it rarely does lasting harm. Cicadas do not eat leaves, flowers or fruit, so gardens and crops are generally safe. In this they are very different from locusts such as the desert locust, which chew through crops, even though settlers in North America called periodical cicadas “locusts”.

Other ways cicadas can bother people

The main nuisance from cicadas is noise. A chorus of periodical cicadas can approach 100 decibels close to the trees, loud enough to make conversation difficult. Their clumsy flight also brings them bumping into people, windows and cars, and empty nymph skins pile up on trunks, fences and walls.

After some periodical cicada emergences, people in the Midwest and mid-Atlantic have reported itchy red bites. The cause was not the cicadas but tiny oak leaf itch mites, which multiply by feeding on cicada eggs in twigs and can drop onto people from trees.

Why so many animals eat cicadas

Cicadas are large, slow, juicy and defenseless, which makes them easy food. During an emergence, birds from crows and grackles to robins and blue jays gorge on them, and squirrels, raccoons, opossums, skunks and foxes join in. Turtles, frogs and fish snap up cicadas that fall into water, and copperheads and other snakes have been seen eating newly emerged cicadas.

Specialist predators exist too. The eastern cicada killer, a large solitary wasp, hunts the annual cicadas of midsummer, paralyzing them with a sting and dragging them into its burrow to feed its young. A fungus, Massospora cicadina, infects periodical cicadas and turns the rear of the abdomen into a mass of spores. The sheer number of cicadas in a periodical emergence is their only defense, as explained in Why do cicadas come out every 17 years?

Cicadas compared with insects that do bite or sting

Like cicadas, dragonflies are often feared but are harmless to people, as explained in Do dragonflies bite? For a cicada, a person is just another tree trunk to rest on before flying off to sing or lay eggs.