Grass-carrying wasps

Brown-legged Grass-carrier on mountain mint

Grass carrying wasps get their name from their habit to carry long pieces of grass which they use in their nests. If you see a flying stem or blade of grass, look again and you will notice the wasp that is carrying it. They are black, slender and with an incredibly long and thin waist. That is why their other common name is thread-waisted wasps. Their wings have a smoky or violet color.

Grass-carrying Wasp, Isodontia mexicana

They can be as large as ¾”. They make their nests inside hollow tubes, such as twigs or holes in wood. Sometimes they use the tracks of window screens or window frames which they stuff with grass before placing some prey and an egg. There may be a row of similarly prepared cells. There is nothing to be alarmed; these wasps pose no threat to humans and don’t damage your house. They catch katydids or crickets to feed their young, so they are good pest controls.

Habitat. Fields, open areas, grassy areas.

Season. From March to December in most of North America. Most common in July and August.

Flowers. Many kinds of flowers of the aster family, including goldenrods, also fennel, queen Anne’s lace and sedum

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One Response to “Grass-carrying wasps”

  1. Wildflower Wednesday: common mountain mint Says:

    […] following websites which helped me identify certain pollinating insects: What’s That Bug?, Polizinador’s Blog,  MO Bugs, Galveston County Master Gardeners’ Beneficial Insect List, and Field Station from […]

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