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Solitary wasps

Quick facts

  • Solitary wasps are common beneficial insects in landscapes. 
  • They hunt and capture other insects or spiders to feed their young. 
  • They are not aggressive toward people and rarely sting. 
  • Solitary wasps should be tolerated and ignored whenever possible.
Solitary wasp landing on flowers
Typical solitary wasp

Identifying solitary wasps

Solitary wasps (also called hunting wasps) are a group of related insects primarily consisting of the thread-waisted wasps (Sphecidae) and digger wasps (Crabronidae).

They have the following characteristics:

  • Smooth and shiny body; few hairs.
  • Body ranges from slender to stout.
  • Vary in size from less than 1/2 inch long to 1-1/2 inches long.
  • Vary in color: black and yellow, black and orange, iridescent black or purple.

Insects that may be confused with solitary wasps

Example of a typical bee on a leaf.
Typical bee

Some solitary wasps may be confused with bees. However, bees have hairy bodies and legs, and often are seen carrying balls of pollen on their hind legs. Solitary wasps have few hairs on their bodies or legs.

Solitary wasps, especially digger wasps, may also be mistaken for yellowjackets, although most solitary wasps are larger than yellowjackets.

Solitary wasps and yellowjackets both build nests in the ground. Ground-nesting solitary wasps often build nests in groups with each wasp having its own individual nest. Yellowjackets live together in one nest with many workers going in and out of the single nest opening.

yellowjackets coming out of ground nest
Ground nesting yellowjacket nest
solitary wasp coming out of ground nest
Typical solitary wasp nest

Biology of solitary wasps

Thread-waisted wasps and digger wasps are commonly seen from June through August.

Most solitary wasps nest in the ground. However, some build nests made of mud and a few nest in cavities, like hollow plant stems or cavities in wood.

  • There is one female wasp in each nest.
  • Some species live gregariously, meaning there are many nests in a small area.

Adult solitary wasps feed on nectar and are commonly seen around flowers. They prey on insects or spiders to feed to their young. A particular solitary wasp attacks a specific type of insect.

  • They sting and paralyze their prey. They either drag them to their nest or pick them up and fly back with them.
  • The females bring a number of prey back to its nest. The larvae feed on the immobilized prey that has been provided for them.

The adult females die by the end of the summer. The larvae eventually pupate and emerge the following summer. There is one generation each year.

Importance of solitary wasps

Natural control

Solitary wasps prey on insects or spiders which helps keep those arthropod populations in check.

Pollination

Solitary wasps can move pollen when they visit flowering plants. Although wasps are not as efficient pollinators as bees, pollen grains can stick to a wasp’s body and transfer between flowers.

Nuisance

Solitary wasps can be a nuisance and cause concern when they nest in lawns or gardens, especially when large numbers are present. They can potentially sting to protect themselves.

  • Fortunately, they are not aggressive to people and there is little risk from them.
  • They do not defend their nests and avoid people when possible.
  • They can sting to protect themselves if they are physically handled.
  • Yellowjackets protect their nests and are much more likely to sting people.

How to live with solitary wasps

Managing solitary wasps is difficult and is unnecessary. Remember, these wasps are beneficial with little risk of stings.

If you find solitary wasps in your landscape:

  • Ignore and tolerate them whenever possible.
  • Solitary wasps are active for just a few weeks.
  • They only live one season and do not reuse nests year after year.
  • Solitary wasps are not aggressive and are unlikely to sting.

Solitary wasps can sometimes still cause concern when found nesting where people, especially children, are present. In cases where it is difficult for residents to ignore the nests, there are few options that can be attempted.

Management options in turf

In lawn areas, the best management is to treat each individual nest with insecticidal dust labeled for ground-nesting insects, e.g. permethrin. Spraying the nest area with a liquid insecticide is not very effective.

Management options in playgrounds or sandboxes

Sand wasps or other digger wasps that nest in sandboxes or playgrounds are difficult to manage once they have started nesting. Using a pesticide where children play is not recommended.

It might be possible to discourage wasps from nesting in an area.

  • Frequent raking of the nesting area may cause them to nest somewhere else.
  • Laying a tarp over the nests for several days may also discourage them from that area.

Mud dauber nests

When mud dauber nests are found on a home, ignore them or remove the nests with a putty knife. They do not defend their nests so there is little to no risk of stings.

CAUTION: Mention of a pesticide or use of a pesticide label is for educational purposes only. Always follow the pesticide label directions attached to the pesticide container you are using. Remember, the label is the law.

Thread-waisted wasps

Thread-waisted wasps (Sphecidae) have a conspicuous, long, thin segment called a petiole between the abdomen and thorax (it is actually part of the abdomen). This gives the body its "thread-waisted" appearance. Common colors are black with yellow or orange or metallic purple or black.

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Digger wasps

Digger wasps (Crabronidae) are more compact and robust than their thread-waisted cousins and are usually black and yellow with striped abdomens, resembling yellowjackets.

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Authors: Jeff Hahn, Extension entomologist, Jim Walker, Department of Entomology, and Julie Weisenhorn, Extension horticulture educator

Reviewed in 2021

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