Bizarre and vibrant: getting to know Montana's cuckoo wasps

The tiny wasp shimmered between my fingertips, its hard exoskeleton glittering green and blue under the strong June sun. Nearby, along the base of the shaly orange slope, was the patch of leafy spurge where I had captured it as it had gathered nectar from the showy yellow spurge blooms. I had started seeing cuckoo wasps several weeks ago near this western Montana grassland stream, crawling across the ground and visiting flowers among the busy profusion of early-summer vegetation. The cuckoo wasps I was seeing, roughly the size of rice grains, varied somewhat in their appearance. But all of them were striking. Most ranged from emerald to a deep blue-green. Some shone coppery red in the light. And the more I learned about these tiny, often-overlooked wasps, the more interesting they became.