Maryland Native Pollinators and Plants to Support Them – Thread-waisted Wasp

Jan 19, 2026 | Blog, Educational

Native Pollinator Spotlight: Thread-waisted Wasp (Palmodes dimidiatus)

Palmodes dimidiatus – University of Wisconsin Milwaukee

We saw a curious scene on the nursery floor this past summer: a frantic black and red insect, which upon closer inspection turned out to be a thread-waisted wasp in the act of hunting prey, carrying some large cargo! There are many members of the thread-waisted wasp family in Maryland, but we believe this particular one was Palmodes dimidiatus, a species without a common name. When we found her, she had already found and paralyzed her prey — a katydid as large as she was — and was busy trying to find a spot on the ground beneath some of our shelves where she could dig a hole to store the katydid in with one of her eggs.

All female thread-waisted wasps (and most stinging solitary wasps in general) share a similar behavior: they will find prey, paralyze it with their sting (only females have stingers), then hide it away somewhere with an egg. When that egg hatches into a wasp, it feeds on the paralyzed prey. These wasps have figured out a brutal yet efficient method of securing a food source for their newly hatched young.

In addition to preying on herbivorous insects and keeping those populations in check, these wasps also visit flowering pants to fuel up on nectar for their bouts of hunting and therefore act as pollinators. They especially like flowers with abundant nectar, such as mountain mint (Pycnathemum spp.). Though these wasps may seem scary, they are completely non-aggressive to humans and shouldn’t be any cause for concern.