Bicyrtes quadrifasciatus (four-banded sand wasp / “stink bug hunter”)
Photo: Stink Bug Hunter, Hood Street, August 2025
Snapshot
What it is: A native, solitary sand wasp that hunts true bugs—especially stink bugs—and nests in loose, sunny sand. Great garden ally.
Range: Broadly across eastern North America (into CO/WY on the west side of its range).
When you’ll see adults (Chicago & other northern areas): roughly mid-June/July through September.
Ecological role
Predator of crop/garden pests: Females paralyze and stock their nests with nymphs/adults of Pentatomidae (stink bugs), plus some Scutelleridae, Reduviidae, and Coreidae—including the invasive brown marmorated stink bug. This makes them valuable natural biocontrol.
Pollinator: Adults drink nectar at a variety of native wildflowers; while feeding, they move pollen around.
Life cycle & behavior
Nesting: Solitary ground-nester in bare or sparsely vegetated, loose sand—beaches, old dunes, sand prairies, sandy paths, etc. Females often form loose aggregations where the substrate is ideal. Burrows can be ~12″ deep with 1–3 cells.
Hunting & provisioning: A female captures several true bugs, carries each back clutched in her mid-legs, re-opens the burrow, and mass-provisions each cell with about 4–14 prey before laying an egg and sealing it.
Generations: Typically one generation per year (univoltine) in the north; longer activity window in the south.
Natural enemies: Kleptoparasitic flies may follow females into nests and lay eggs on the stored prey, which can rob the wasp larva of its food.
Identification quickies
Medium-sized black wasp with four pale bands on the abdomen (males may look a bit different), yellowish legs; often seen zipping over sand or tanking up on nectar.
Best native plants to support it (Chicago ecoregion friendly)
These are known nectar plants used by B. quadrifasciatus (grow a mix to cover bloom from mid-summer into fall):
Indian/pale Indian plantain (Arnoglossum spp.)
White prairie clover (Dalea candida)
Goldenrods (Solidago spp.)
Black-eyed Susan (Rudbeckia spp.)
Habitat tips (what to do in your yard)
Leave a sunny sand patch: Maintain a bare, well-drained sandy area (even a 2–4 ft² spot works) with minimal foot traffic for nest sites. Don’t constantly water or mulch it.
Plant the nectar list above near that patch so females can refuel between hunts.
Avoid insecticides, especially during bloom; these wasps are sensitive and you don’t want to poison their prey pipeline. (General best practice reinforced by their role as beneficials.)
Expect company: Where conditions are perfect, you may see small colonies of individual nests—normal, and usually gentle if left alone.
