Sand wasp - Bembix

Eastern Washington

Bembix sand wasps are bluish-white and black striped ground wasps which dig solitary burrows in sand to rear their young. Bembix sand wasps specialize on catching flies, including hover flies (syrphids), tachinid flies, sarcophagids, calliphorids, muscids and other flies to provision their nest burrows as their larvae grow. They paralyze or even kill flies with their sting, then stuff the prey in their solitary burrows as available for their developing young to eat. Their life history differs from other predatory wasps, which accumulate larval provisions first (mass provisioning) and then seal up the nest burrow with larvae inside.

Adults bembix wasps feed on flower nectar. They are very fast diggers in sand, able to disappear below the surface of loose sand within seconds.

Velvet ants (Mutillids) likely raid sand wasp nests to lay their eggs on mature larvae, as they do with other predatory wasps, no doubt reducing Bembix populations to some extent. Thick-headed flies also parasitize sand wasps-- in an apparent show of brinksmanship, a female thick-headed fly will boldly intercept a wasp in flight and pry apart abdominal segments to lay her egg, which hatches as an internal parasite developing in its host wasp without necessarily killing it.

» Other Eastern Washington wasps

Bembix sand wasp

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