Cicadas

Quick facts about cicadas

  • Adult cicadas produce a power line like sound and their presence can be identified by that sound.They are found in urban and rural areas wherever hardwood trees are present.
  • Cicadas are active July through September.
  • They are harmless to people, plants and property.
  • No control is necessary.

Cicadas have sometimes been described as beetles with wings sticking out. The nymphs have been described as ‘beetles that turn into flies'.

Cicadas are closely related to leafhoppers, planthoppers and spittlebugs.

There are two basic types of cicadas:

  • Dog day cicadas (Tibicen spp.) are also called annual cicadas. They are seen every year in Minnesota.
  • Periodical cicadas cicadas do not occur in Minnesota. They spend 13 or 17 years as a nymph in the ground and then emerge together in large numbers.

How to identify cicadas

Adult cicadas

A green brown insect with clear wings longer than the abdomen
Dogday cicada
  • Cicadas are 1 - 1 1/2 inches long.

  • They are stout with a green or brown body and black markings on the body.

  • They have four, clear, fly-like wings and the first pair is much longer than their abdomen. The wings which are folded over their back look like a tent.

  • They also have very short antennae.

Immature nymphs

A brown beetle-like insect on a tree bark
Cicada nymph
  • They are dark brown and look similar to the adults.

  • They do not have wings.

Some people think they look like beetles (because they look stout and do not have wings).

Behavior and habits of cicadas

Adult cicadas

A brown insect with clear wings and antennae
Dogday cicada adult
  • Cicadas are present from July to September.
  • You may not see them, but you will hear the distinct humming sound made by cicadas.
  • They produce a high-pitched sound during the day that resembles a powerline hum.

Only the males produce this sound in order to attract females. They produce this hum by vibrating a membrane in an internal air chamber.

Nymphs

A brown beetle-like insect cast that is hollow inside
Cicada 'cast skin'
  • It is more common to see immature nymphs than adult cicadas.
  • The nymphs spend four to eight years underground, feeding on plant and tree roots, especially perennials.
  • Once they come out from the ground, they climb up objects such as trees, posts, fences and even the sides of buildings to molt into adults.

When cicada nymphs molt into adults, they leave behind 'cast skins'. The cast skins may look like an insect, but it is hollow inside.

Damage caused by cicadas

  • Despite their size, cicadas are NOT harmful or dangerous to people, pets or property in any stage.
  • While they do feed on trees, they do not cause any noticeable injury.
  • But, cicadas could injure trees when they use their sharp ovipositor to lay eggs in twigs.

If you see cicadas, just ignore them and they will go away on their own.

Jeffrey Hahn, Extension entomologist

Reviewed in 2018

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