Cicadas are large, winged insects famous for their periodic emergence and loud buzzing chorus. These creatures spend most of their lives underground as nymphs, surfacing briefly to reproduce. While their sudden, massive appearance can be startling, entomologists agree that cicadas pose virtually no direct threat to human health. Concerns usually revolve around misconceptions about their feeding habits and the nuisance caused by their sheer numbers.
The Myth of the Cicada Sting and Bite
Cicadas do not possess the mouthparts necessary to bite aggressively or defensively in a way that is harmful to humans. Unlike mosquitoes or biting flies, cicadas are equipped with a long, needle-like proboscis designed solely for piercing plant tissue. This specialized mouthpart is used to access and drink xylem fluid, or sap, from trees and shrubs. They are obligate plant-feeders and do not seek blood or human flesh.
The rare sensation of a “cicada bite” is generally a momentary, accidental probing. A cicada that lands on a person may mistake the skin for a plant stem and attempt to feed, resulting in a slight, harmless poke or pinch. They lack stingers for venom delivery and do not have mandibles capable of tearing flesh. Any brief discomfort results from their mistaken identity, not an intentional attack.
Health Concerns: Toxicity and Disease Transmission
Cicadas are not toxic or venomous to humans or pets. They do not inject venom and are not considered poisonous if consumed, which is why they are occasionally prepared as a food source. Cicadas are not vectors for human disease; they do not carry or transmit pathogens like viruses or bacteria in the way that ticks or mosquitoes do.
A minor health consideration relates to consumption and allergies. Individuals with known shellfish allergies should exercise caution, as cicadas are arthropods and share biological similarities with crustaceans. The hard outer shell, or exoskeleton, is made of chitin, which is difficult to digest. Eating a large volume of the insects can cause temporary gastrointestinal upset, vomiting, or diarrhea, but this is a mechanical digestive issue.
Nuisance vs. Danger: Indirect Risks
The risks associated with cicadas are indirect and primarily related to annoyance or property damage. The males produce mating calls using specialized abdominal membranes called tymbals, and these calls can reach high volumes. Chorus noise levels can exceed 90 to 100 decibels at close range, comparable to a lawnmower or a small motorcycle. Prolonged exposure to sound above 85 decibels can cause hearing damage, making ear protection advisable near dense aggregations.
Female cicadas pose a risk to young or newly planted trees through oviposition. They slice small slits into pencil-sized twigs and branches to lay their eggs, which can cause the tips of branches to die and brown, a phenomenon known as “flagging.” While mature, healthy trees withstand this natural pruning, younger trees may need to be covered with fine netting to prevent permanent damage. For pets, the main risk is overconsumption, as eating too many cicadas can lead to digestive distress or, for smaller animals, a choking hazard.