European Paper Wasp
insect profile: European Paper Wasp – beneficial or harmful?
The European paper wasp -Polistes dominulus is native to the Mediterranean. It was first discovered in the eastern U.S. in the late 1970s and has rapidly increased throughout the United States.
- European Paper Wasp, Dominulus Paper Wasp
- Throughout Europe & Asia; North America – northeastern US, Florida, Ontario, British Columbia, Washington to California and east to Colorado
- March – Late Fall; Fertilized queens overwinter in protected sites.
- Larvae are fed masticated caterpillars and other insects. Adults drink nectar from flowers and rotting fruit.
- Extremely adaptive to a wide range of habitats, including urban areas.
- Not native to North America. Not aggressive except around nests.
- High beneficial value for biological control. Low beneficial value for native ecosystems; has the potential to become very invasive.
This species is much more adaptive than many of our native species and has very few natural enemies here in the United States. Most entomologists would agree that this non-native paper wasp is invasive and may be a threat to our native ecosystems.
On the flip side, European paper wasps may be beneficial; they are excellent predators of many pest insects and have become one of the most important natural controls of many kinds of yard and garden insects. Larvae are fed masticated caterpillars and other insects (our native species prey only on caterpillars). Also, adults feed on nectar from from flowering plants and can be considered light pollinators.
However, these wasps may have a negative impact on rare or endangered butterflies, our native paper wasps, and birds nesting in boxes, a common nesting site for European paper wasps. Since this is a relatively new introduced species, its overall impact may not be known for quite some time.
Personally, I have noticed a significant decrease in moth and butterfly populations within the garden this year due to the caterpillars becoming ‘wasp baby food’ before they could complete their life cycle. There also has been an abundance of many other predatory wasp species (including the Southern yellowjacket -Vespula squamosa, which is uncommon in Michigan), so the European paper wasp is likely not entirely responsible for this decrease.
European paper wasps are generally not aggressive while foraging in the garden or landscape, but are protective of their nests which are often hidden in dark cavities such as outdoor grills, cracks in walls, screen vents and eaves. They prefer to attach their nests to wood, rusty metal or rock. Nests observed away from human traffic should be left alone. These nests will be abandoned in the late fall and will not be reused.
If a nest is found in an area where it will be disturbed, it should be destroyed at night (while the workers and queen are on the nest) with a wasp spray. – Always read and follow directions & safety precautions on labels - The nest then should be removed and destroyed to ensure all the larvae are killed that may have been within capped cells during spraying.
Suitable nest sites can be avoided by keeping cracks and crevices around windows, eaves and vents caulked and sealed. A wooden nesting box, at least 4 inches square; with an open bottom; mounted several feet off the ground, can also be used to encourage nesting away from human structures. More information about nest box construction can be found here: Using Paper Wasps for Caterpillar Management in the Landscape
Please use caution when using insecticides in & around your garden or yard, as it will likely kill important beneficial insects that are a very effective control of a wide range of plant eating pests!