What Do Cicadas Eat? Depends How Old They Are

OK, cicadas do have a bit of a sweet tooth, but not like this. Fernando Trabanco FotografÃa / Getty Images

"What do cicadas eat?" is a great question because these noisy insects have a surprising diet.

Unlike grasshoppers or other insects that chew their food, cicadas use specialized sucking mouthparts to extract fluids from nearby plants. They spend most of their lives underground, feeding on plant roots, before emerging in large groups to complete their life cycle.

Cicadas live on tree roots for years when they're nymphs, slowly developing before reaching their adult stage. When mature cicadas emerge, they don’t eat much — just enough to survive their short, few-week lifespan above ground.

Cicada Nymphs Suck on Plant Roots

Before becoming loud, buzzing adults, cicadas spend the majority of their lives underground burrowing among plant roots. The young nymphs use their sucking mouthparts to tap into tree roots, drawing out nutrients to grow and develop.

This stage can last anywhere from a few years for annual cicadas to 13 or 17 years for periodical cicadas, such as those in the genus Magicicada, including Brood X and other cicadas that appear in cycles.

While most cicadas stay hidden underground for years, when the time is right, they tunnel to the surface and prepare to molt into adults. The nymph anchors itself onto a nearby branch or tall grass and wrests its adult body from the now useless exoskeleton.

Adult Cicadas Eat Plant Sap

Once cicadas emerge from the ground, their primary goal is to attract mates and reproduce, not to feast.

Adult cicadas feed on plant sap by inserting their mouthparts into young twigs and small branches of trees and woody shrubs. However, they don’t consume much food, as their adult stage is short-lived, usually only lasting a few weeks to a month.

While cicadas bite trees, they don’t bite humans or animals. Unlike many insects, cicadas do not damage crops or plants significantly, though they can cause some cosmetic damage to newly planted trees when female cicadas lay eggs in tree branches.

Are Cicadas Harmful to Plants?

Cicadas are not major plant pests, but their egg-laying behavior can harm young trees. Female cicadas use a saw-like structure to cut into tree branches and lay their eggs inside. This can weaken young twigs and cause minor damage to young trees, but mature trees usually recover quickly.

While cicadas eat plant fluids, they are opportunistic feeders that don’t destroy plants in the way that locusts do. Instead, cicadas play an important role in the ecosystem by aerating the soil when they emerge and providing a massive food source for birds and other animals.

The Role of Periodical Cicadas in Nature

Cicadas provide food for many species, including birds, cicada killers (large wasps that hunt them), and other predators.

When millions of adult periodical cicadas emerge at once, they overwhelm their predators, ensuring that enough survive to reproduce. The last emergence of a Magicicada periodical cicada brood, Brood X, demonstrated how cicadas can influence an entire ecosystem for a short period.

While cicadas may seem like a nuisance due to their loud calls and bright red eyes, the insects deserve some respect for surviving for millions of years.

The next time you see one with black veins on its membranous wings, remember: It has spent most of its time underground, just waiting for its moment in the sun!

We created this article in conjunction with AI technology, then made sure it was fact-checked and edited by a HowStuffWorks editor.