The Back 40, my tiny backyard, is dominated by the overhang of the balconies the upstairs neighbors enjoy. Rusting I-beams support this addition to the building. I recently glanced up and found that one of the beams supports something else entirely.
Thanks to the good people at Bug Guide, I can tell you that this mud structure is a nest of the black and yellow mud dauber wasp, Sceliphron caementarium. Not only did the female wasp spend an awful long time this fall putting this nest together with little daubs of mud (it’s about 4″x2″), but she also provisioned it with paralyzed spiders as well. (Unfortunately, I missed the entire process.) Evidently, the mature larvae are inside here in separate cocoons, over-wintering, and should pupate in the spring.
Mud daubers are members of the sphecid family of wasps. Most have absurdly long “wasp waists.” They look fearsome, but are not aggressive to primates like us. I’m familiar with the organ pipe mud dauber, T. politum, having seen their nests in Prospect Park. The blue dauber, C. californicum, which is also found in these parts, re-uses the nests of the black & yellow for its own brood, so I will not be removing this nest come spring. Home is where you make it.
I hope I’m around to see these wasps emerge; of course, there’s always the chance they’ve been parasitized by other wasps… life is complicated.
The lifeforms that show up in the Back 40 continue to surprise me. But then that’s the whole inspiration for this blog, isn’t it? Even here — in concrete and steel and, temporarily, piles of snow, as well as unprecedented human assault — wildness is.
Backyard and Beyond 
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