2012-08-13

Scolia dubia, Blue-Winged Digger Wasp

Scolia dubia, Blue-winged Digger Wasp, on Pycnanthemum, Mountain-Mint, in my garden.
Scolia dubia, Blue-winged Digger Wasp, on Pycnanthemum, Mountain-Mint

Another little jewel of a wasp that is new to me this year. I've been seeing it on the Pycnanthemum, but was unable to get decent photos of it until yesterday. I've also seen it on the Clethra alnifolia, Summersweet in my garden, which just started blooming in the past week.


With the wings held back, the blue iridescence of the wings might lead one to mistakenly identify this as a small Sphex pensylvanicus, Great Black Wasp.

Scolia dubia
Scolia dubia, Blue-winged Digger Wasp, on Pycnanthemum, Mountain-Mint

Sphex pensylvanicus
Sphex pensylvanicus, Great Black Wasp, on Pycnanthemum, Mountain-Mint

But once the wings spread to the sides, the exposed abdomen distinguishes it. The cinnamon- colored abdomen and two bright yellow spots make for a clear identification, once you know the species.
Scolia dubia, Blue-winged Digger Wasp, on Pycnanthemum, Mountain-Mint

Adults feed on nectar, which both the Mountain-Mint and Summersweet offer in abundance.
Scolia dubia, Blue-Winged Digger Wasp, on Clethra alnifolia, Summersweet

Females dig in search of grubs of June Bugs and Japanese Beetles to parasitize with their eggs. The wasp larva feeds on the beetle grub and overwinters as a cocoon, emerging the next year.

This species is another example of the importance of providing habitat for wasps in the garden; they are natural bio-controls of other insects that might otherwise overwhelm the gardener's intentions.

Related Content

Flickr Set: Scolia dubia, Blue-Winged Wasp

Links

BugGuide: Blue-winged Wasp (Scolia dubia)

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