Wasp Waist

The wasp has a narrow waist. It is so narrow that it looks as if it is hardly there. Why does a wasp have such a small waist?

A waist is the middle part of an animal’s body. In an insect, the waist is between the thorax (chest) and the abdomen (stomach).

The wasp waist is called a petiole.

Black Spider Wasp

Scientists that study insects are called entomologists. Entomologists think that about 250 million years ago, which is the start of the Triassic period, a species of insect evolved with a very narrow waist. It was an insect in the family of wasp-waisted insects.

The female of these wasps has a large ovipositor, which is a tube on its tail that is used to lay eggs. The ovipositor is also the stinger, used to inject poison into their prey. The male wasp does not lay eggs and it does not sting. 

Scientists think that its waist is so narrow to enable a lot of flexibility and manoeuvrability. Therefore, the petiole is like a hinge. It means that the female wasp can curl her abdomen to lay eggs and to sting its prey.

Even though the waist is extremely thin, it does contain nerves and veins, and other structures. 

Black Spider Wasp

Photographer: Martina Nicolls


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