Cicadas do not bite or sting in any way that poses a threat to people. They have no stinger, no venom, and no inclination to attack humans. Their needle-like mouthparts are built to pierce tree bark and suck up watery sap, not to puncture skin in self-defense. On very rare occasions a cicada may probe a person’s arm or hand with its feeding tube, apparently mistaking a warm limb for a branch, but even then the sensation is closer to a pinprick than a true bite. The real hazards associated with cicadas are far more indirect and unexpected than most people assume.
Why Cicadas Cannot Sting
Stinging is a defensive act, and cicadas simply lack the equipment. Bees, wasps, and hornets possess a modified ovipositor connected to a venom gland. Cicadas have neither structure. They belong to the order Hemiptera, the “true bugs,” whose defining feature is a set of piercing-sucking mouthparts called a rostrum. This straw-like beak sits folded beneath the head and is used exclusively for feeding on plant fluids. When a cicada lands on you and you feel its legs gripping your skin, that grip can startle, but it is not a sting or a bite in any predatory or defensive sense.
What Their Mouthparts Actually Do
A cicada’s mouthparts are engineering marvels shaped by millions of years of evolution for one purpose: drilling into tough plant tissue. The outer stylets, called mandibles, do the heavy cutting. Research comparing the material properties of cicada mouthparts found that the tips of these mandibles are enriched with manganese and zinc, making the distal regions significantly harder than the rest of the structure. That mineral reinforcement allows cicadas to bore through woody stems to reach the xylem vessels inside.
1MDPI (Biology). Comparative Material and Mechanical Properties among Cicada Mouthparts: Cuticle Enhanced with Inorganic Elements Facilitates Piercing through Woody Stems for FeedingUnderground, cicada nymphs use the same basic design to tap into tree roots. Histological work on roots where nymphs had fed confirmed that their salivary sheaths ended exclusively in xylem vessels, meaning these insects spend their entire development drinking xylem fluid, a liquid so nutritionally dilute that it may explain why periodical cicada nymphs need 13 or 17 years to reach adulthood.
2Ecological Entomology. Xylem feeding by periodical cicada nymphs on tree rootsSo when a cicada lands on a person and tentatively probes exposed skin, it is attempting to feed, not to defend itself. The probe rarely breaks the skin, and if it does, the result is a brief, mild prick with no venom involved. Most people who handle cicadas regularly never experience even that.
How Cicadas Defend Themselves Instead
If cicadas cannot sting or bite aggressively, how do they survive? Their primary strategy is sheer numbers. Periodical cicadas emerge in synchronous broods so massive that local predators physically cannot eat them all. This tactic is known as predator satiation, and it works precisely because the cicadas themselves are defenseless as individuals. Birds are the major predators of adult periodical cicadas, and during an emergence they gorge themselves, yet billions of cicadas still survive long enough to mate.
3PubMed. Red-winged blackbird predation on periodical cicadas (Cicadidae: Magicicada spp.): bird behavior and cicada responsesAnnual cicadas, which appear every summer in smaller numbers, rely more on camouflage, erratic flight, and their loud alarm squawk when grabbed. That startling buzz a cicada makes in your hand is about as aggressive as it gets. None of these responses involve biting, stinging, or delivering any chemical irritant to a person.
The Actual Dangers Cicadas Pose to Humans
Cicadas are harmless in the traditional sense, but they have caused real injuries in emergency departments, just not through biting or stinging. A case analysis of cicada-related emergency visits found that the injuries were almost entirely self-inflicted through panic. Two patients leaped from moving vehicles after cicadas flew in through open windows. Others were hurt while trying to swat, kill, or flee from the insects. The list of injuries included a hand laceration from trying to kill a cicada with a weed whacker, a reopened surgical wound after being swarmed during outdoor physical therapy, an arm injury from falling off a scooter, a chest injury from running into a safety pole, and a head injury from running into a wall.
4Western Journal of Emergency Medicine. Clinical Insights and Case Analysis of Disorders Attributed to Cicadas in the Emergency Department – Section: DISCUSSIONThe pattern is clear: the danger isn’t the cicada itself, it’s the human reaction to a large, loud, clumsy insect flying into your personal space. Cicadas are poor fliers and frequently crash into people, cars, and buildings, which understandably triggers alarm in anyone who doesn’t know the insect is harmless. Staying calm when one bumps into you is genuinely the best safety advice anyone can offer during an emergence.
Allergic Risks If You Eat Them
Eating cicadas has a long history in many cultures, and with the growing interest in edible insects as sustainable protein, more people are considering trying them during big emergences. For most people, cooked cicadas are safe to eat. But there is a real and clinically relevant allergy risk for one group: people who are allergic to shellfish.
Cicadas, shrimp, crab, and lobster are all arthropods, and they share conserved proteins, particularly tropomyosin and arginine kinase, that act as pan-allergens across the group. A systematic review of allergic risks from edible insects found that cross-reactivity between edible insects and crustaceans appears clinically relevant.
5PubMed. Allergic risks of consuming edible insects: A systematic review A more recent review confirmed that these pan-allergens are widely conserved across insect species and are strongly implicated in cross-reactivity with both crustaceans and house dust mites.6Sustainable Food Proteins. Edible Insect Allergens: An Emerging Food Safety Challenge
If you have a known shellfish allergy, cicadas are not a safe experiment. The reaction can be just as severe as eating shrimp. People with dust mite allergies may also want to exercise caution, though the clinical picture there is less settled. For everyone else, cicadas that have been properly cooked and sourced from areas not treated with pesticides are considered safe to eat.
Heavy Metals in Cicada Bodies
Because cicada nymphs spend over a decade underground feeding on root fluid, they can accumulate whatever is in the surrounding soil. Research on periodical cicadas found that metal concentrations in the nymphal exoskeleton correlated positively with soil metal concentrations, with some elements like gold showing particularly strong enrichment relative to what was in the soil. Heavy metals tend to accumulate in the keratin-rich tissues of the exoskeleton.
7PubMed. Influence of soil chemistry on metal and bioessential element concentrations in nymphal and adult periodical cicadas (Magicicada spp.)This matters more for people who live in urban areas with contaminated soils and are thinking about harvesting cicadas to eat. A cicada that spent 17 years in soil laced with lead, mercury, or cadmium will carry some of that contamination in its body. Eating a handful probably won’t cause harm, but making cicadas a regular dietary feature from polluted ground is a different calculation. If you’re foraging, sourcing from parks or forests away from highways, industrial sites, and old lead-paint zones is a sensible precaution.
The Fungus That Hijacks Cicada Behavior
One of the strangest stories in cicada biology involves a parasitic fungus called Massospora, which infects cicadas and essentially turns them into zombies. The fungus consumes the insect’s abdomen from the inside out, replacing it with a chalky mass of spores, yet the cicada keeps flying and even attempting to mate, spreading spores to other individuals. Researchers discovered that Massospora species produce psychoactive compounds during infection: cathinone, an amphetamine previously known only from plants, and psilocybin, a compound previously known only from certain mushrooms.
8PubMed Central. Psychoactive plant- and mushroom-associated alkaloids from two behavior modifying cicada pathogens – Section: DiscussionThe discovery was remarkable because it was the first evidence of amphetamine production in any fungus and of psilocybin production outside the mushroom lineage. The hypothesis is that these chemicals manipulate the cicada’s behavior, keeping it active and social even as its body is destroyed, which benefits the fungus’s transmission. This is not dangerous to humans in any direct way, but it does mean that a small percentage of cicadas during any emergence are walking around drugged and hollowed out. You can sometimes spot infected individuals by the pale, crumbly plug of spores where their abdomen should be. Eating one wouldn’t deliver a meaningful dose of either compound, but it’s one more reason to inspect what you’re harvesting.
What Cicadas Actually Damage
While cicadas are harmless to people, they can be rough on young trees. The damage comes not from feeding but from egg-laying. Female cicadas use a saw-like ovipositor to slice into small branches and deposit eggs in the slits. On mature trees, this “flagging,” where the branch tips turn brown and droop, is mostly cosmetic. But on young, recently planted trees, the effect can be significant.
A survey of newly planted trees in Washington, D.C. found significant differences in egg-laying damage across tree types, with maples and black gums receiving the most attention. Egg laying concentrated in scaffold and lateral branches, and the intensity of oviposition correlated positively with the percentage of foliage the tree lost.
9Arboriculture & Urban Forestry. Impacts of Periodical Cicada Egg Laying on Young Trees in the District of Columbia and Limitations of Using Remote Sensing Products to Assess Their DamageThe practical takeaway for homeowners is straightforward: if a periodical cicada emergence is expected in your area, delay planting new ornamental trees by a year, or protect young saplings with fine netting during the four-to-six-week emergence window. Established trees almost always recover fully. The oviposition scars even act as a natural pruning mechanism on large, healthy specimens.
What Cicadas Give Back to the Ecosystem
A periodical cicada emergence is one of the largest insect events in nature, and it sends ripple effects through entire food webs. When billions of cicadas die after mating, their bodies carpet the forest floor and deliver a massive pulse of nutrients to the soil. A study in Science found that these resource pulses directly increase microbial biomass and nitrogen availability in forest soils, with indirect effects on the growth and reproduction of forest plants.
10PubMed. Periodical cicadas as resource pulses in North American forestsFollow-up work added some nuance. A longer-term experiment that added cicada bodies to soil around sycamore trees found that while plant-available nutrients did increase and bacterial-feeding and fungal-feeding organisms in the soil multiplied, tree growth itself was not measurably affected over four years.
11PubMed Central. Acute resource pulses from periodical cicadas propagate to belowground food webs but do not affect tree performance So the nutrient boost clearly reaches the microbial food web underground, even if it doesn’t always translate into bigger trees.
Above ground, the effects on animal behavior during an emergence are dramatic. A study tracking the 2021 Brood X emergence found that more than 80 bird species opportunistically switched their diets to include cicadas, which had an unexpected cascade: with birds busy gorging on cicadas, caterpillars went unpoliced, roughly doubling both caterpillar densities and the leaf damage they inflicted on oak trees.
12PubMed. Periodical cicadas disrupt trophic dynamics through community-level shifts in avian foragingMammals respond too, though less uniformly. Camera-trap monitoring during Brood X in Indiana found that raccoons clearly responded to cicada abundance, possibly hitting a saturation point at high densities. Most small mammals and squirrels showed no measurable change in activity. One surprise: white-tailed deer activity dropped to near zero in areas of peak cicada density, possibly because the deafening chorus made it harder for deer to listen for predators.
13Journal of Mammalogy. Activity responses of a mammal community to a 17-year cicada emergence eventCicadas Compared to Insects That Actually Do Bite
Part of the confusion about cicadas comes from mistaken identity. Cicada killers, the large solitary wasps that hunt cicadas, are frequently mistaken for cicadas themselves. These wasps can sting, though they rarely do so unless handled. People sometimes see a cicada killer dragging a paralyzed cicada across their patio and assume it’s the cicada doing the attacking. The wasp is the predator; the cicada is the prey.
Cicadas also get lumped in with other loud summer insects. Katydids, locusts (which are actually swarming grasshoppers), and large beetles all share the “big, buzzy, possibly dangerous” category in many people’s minds. Among these, only certain beetles and some large grasshoppers can deliver a noticeable pinch. Cicadas remain near the bottom of the threat scale for any insect you’re likely to encounter.
Even among the true bugs, their closest relatives, cicadas are unusual in their complete harmlessness to humans. Assassin bugs and kissing bugs, fellow members of Hemiptera, can deliver painful, medically relevant bites. Cicadas share the same basic mouthpart blueprint but have adapted it solely for the slow, patient work of sipping dilute tree sap. They have no reason to bite you, no ability to sting you, and nothing toxic to deliver even if they tried.
The Noise Factor
If there is one genuinely unpleasant thing a cicada can do to you, it’s assault your ears. Male cicadas produce sound using specialized structures called tymbals on the sides of their abdomen, and during a mass emergence the combined chorus can exceed 90 to 100 decibels at close range, comparable to a lawnmower or a motorcycle. Prolonged exposure at those levels can cause temporary hearing discomfort or, in extreme cases, contribute to noise-induced hearing issues.
People who work outdoors in the middle of a dense periodical emergence sometimes find the sound physically oppressive. Wearing earplugs during peak chorus hours, typically late morning through early afternoon on warm days, is a reasonable measure if you’re spending extended time in heavily wooded areas during an emergence. The chorus fades as temperatures cool each evening and drops off sharply once the emergence nears its end, usually within four to six weeks of the first adults appearing.