Insects certainly slow down in late fall, but there are actually quite a few late season arthropods that will show up on warm and / or sunny days.
The red-legged Pimpla genus wasp is one such specimen you might find in November.
Pimpla wasps are part of the ultra-large Ichneumonidae wasp family. To give you an idea, there are more than 25,000 known species of Ichneumons, but scientists think there may be 75,000 more that haven’t been described or named. It’s stunning sometimes, how much is left to be discovered about insects.
All of the wasps in the family lay their eggs in the larvae or eggs of other insects. The young wasps then feed on the (doomed) larvae. For this reason, these wasps are sometimes introduced to stop the over-saturation of certain moths. For example, Pimpla disparis has been used to attempt to contain the spongy moth.
There are about five species of Pimpla in Oregon, and they lay their eggs in moth caterpillars or pupa. I’m not certain which species is represented in this photo. Some of them aren’t identifiable without a microscope.
Pimpla females have relatively stubby ovipositors, or egg-layers. The wasps are solitary, and they don’t sting or defend a nest.
Adults mainly feed on flowers. Anything flowering this time of year is bound to be crawling with insect activity. Take a look, you might spy a Pimpla wasp.
Stay curious!
See more of Karen’s work here.
Sources:
- Website describing North American Ichneumonids: http://www.ichsofna.org/. Accessed 11/25/24.
- BugGuide page for the genus: https://bugguide.net/node/view/167610. Accessed 11/25/24.