Chrysis sp. “Cuckoo Wasp” Chrysididae

Missoula, MT
May 17, 2016
Robert Niese

Cuckoo Wasps are a massive, possibly polyphyletic group of parasitic wasps. More than half the members of this giant family are placed in the genus Chrysis (more than 1000 species!). Undoubtedly, in the coming years this genus will be stripped, split, and reorganized in favor of a more monophyletic and phylogenetically accurate set of genera. As their common name might suggest, cuckoo wasps lay their eggs in the nests of other wasps, and many specialize on a single host species. This lovely individual appeared to be waiting outside an old nail hole on the side of my house that was occupied by a cavity-nesting wasp of some sort.


Sphecodes (arvensiformis) “Cuckoo Sweat Bee” Halictidae
on Euphorbia esula “Leafy Spurge” Euphorbiaceae

Blue Mountain National Recreation Area, MT
May 16, 2016
Robert Niese

Sphecodes bees are cleptoparasitic, cuckoo-like bees that lay their eggs in the nests of other sweat bees. Despite their outward appearance, these insects are not wasps, but they have converged on a very cuckoo-wasp-like life-history strategy. A female enters the nests of another Halictid, consumes a developing egg and replaces it with her own. Unfortunately, these bees, like the vast majority of Halictids, are very poorly studied and there are few entomologists capable of accurately identifying them beyond the genus level. Oh, and by the way, Leafy Spurge, while it is one of Missoula’s most widespread invasives, is also one of my favorite spring plants. They’re just such odd organisms! More photos and natural history info to come, I’m sure.

Looking back at my other photos of these bees from years ago makes me realize how far my skills as a photographer and natural historian have progressed.


Lasioglossum (Hemihalictus) sp. “Weak-veined Sweat Bee” Halictidae
on Solidago missouriensis. “Prairie Goldenrod” Asteraceae

Apgar Lookout Trail, Glacier National Park, MT
October 9, 2015
Robert Niese

Lasioglossum is the world’s largest genus of bees and contains more than 1700 species worldwide. Like many other speciose invertebrate genera, we know relatively little about these organisms and only a handful of entomologists worldwide are capable of identifying them to species. In the last five years, researchers throughout North America have revised the taxonomy of this group using phylogenetic data, new morphological characters, and over 10,000 museum specimens. According to their keys, this particular individual is possibly a male L. (Hemihalictus) inconditum.

Acraspis macrocarpae “Jewel Oak Gall Wasp” gall, Cynipidae

Missoula, MT
October, 21 2015
Robert Niese

Female jewel wasps are adorable, wingless, pudgy little things when they emerge from these galls in October. Here’s another picture of these cuties for good measure. These unique organisms reproduce in cycles of alternating generations of all females and generations with both sexes. In years with only females, the wasps reproduce parthenogenetically. Apparently, parthenogenetic galls are different in size, shape, and color than their sexually-produced counterparts. I was unable to find specific information regarding this phenomenon in Acraspis macrocarpae, but most accounts suggest that only females occur inside these particular galls, which leads me to believe they may be the sexually-produced versions of these oak galls. Perhaps next year, we’ll see a completely different variety of gall on our local oaks! I’ll be sure to update you all next fall.

Also, fun fact, this species of gall wasp was originally described by Alfred Kinsey, the world-renowned human sex scientist! It’s true! Before studying sex, Kinsey collected more than 7.5 million galls and wasps and named dozens of species. Of the 18 million insect specimens currently housed at the American Museum of Natural History, nearly a third are from Kinsey’s dissertation! His work not only revolutionized our understanding of this wasp family, but also had profound impacts on the ways we conducted phylogenetic and entomological analyses. Read more about his fascinating work as an entomologist here.

Enicospilus “americanus” species complex, Ichneumonidae

Clinton, MT
July 25, 2015
Robert Niese

This elegant wasp is a parasitoid of Saturnid and Sphingid moth caterpillars. Females lay their eggs on the bodies of caterpillars and the larvae then grow inside the caterpillar, consuming it and taking its place inside its cocoon. Adults visit flowers at night and are commonly seen at lights. We spotted this individual at our mothlighting event for National Moth Week!

Halictus sp. “Sweat Bee” Halictidae on
Geranium viscosissimum “Sticky Geranium” Geraniaceae

Drinking Horse Mountain, Bozeman, MT
June 3, 2015
Robert Niese

Sticky Geranium, as its name would suggest, is covered in tiny glandular hairs that are quite sticky to the touch. Some have suggested that these sticky glands are capable of capturing and digesting small orgnanisms, making the plant slightly carnivorous. It grows in meadows, Ponderosa Pinelands, and at the edge of sagebrush-steppe habitats throughout the PNW. 

Halictus (Seladonia) tripartitus “Sweat Bee” Halictidae

Missoula, MT
May 13, 2014
Robert Niese

Another species of small Sweat Bee in the genus Halictus. If you’re interested in attempting to identify these bees with a dichotomous key (there are only 10 species in the Northwest, so it’s not too difficult!), check this one out here. Once you learn more about these little guys, you start noticing them everywhere!

Andrena “Mining Bee” Andrenidae
on Ranunculus glaberrimus “Sagebrush Buttercup” Ranunculaceae

Council Grove State Park, MT
March 16, 2015
Robert Niese

Andrena is one of the world’s largest genera of bees. There are probably only a few people in all of North America who possess the specialized knowledge necessary to make a reliable species identification. Andrena bees are remarkably cold tolerant and are some of the first small bee species to frequent flowers in the spring, although this little guy was clearly struggling with the chilly morning air.

Sphecodes (arvensiformis) “Cuckoo Sweat Bee” Halictidae
on Lomatium “Biscuit Root” Apiaceae

Missoula, MT
May 13, 2014
Robert Niese

Sphecodes bees are cleptoparasitic, cuckoo-like bees that lay their eggs in the nests of other sweat bees.

Halictus ligatus “Sweat Bee” Halictidae on Aster (Asteraceae)

Missoula, MT
September 2, 2013
Robert Niese

Sweat Bees in the genus Halictus can be difficult to identify, but fortunately, as compared to other genera in our area (see Lasioglossum), there are relatively few species in the Northwest (10). If you’d like to take a shot at IDing your own photographs, check out this key to our species.