09/12/2026
I talked about some of our stinging critters yesterday. Here's another species that I find really fascinating and kind of beautiful in a ridiculous way.
The yellow-legged mud-dauber wasp (Sceliphron caementarium) has an uncomfortably thin section connecting the thorax and abdomen, called a petiole. It looks like a very unsafe thing to have, and my wretched brain cannot stop trying to imagine things like dogs, cats, and humans having the same. No thank you.
The petiole does serve a purpose - these wasps fortify their nests with lots of paralyzed spiders as food for their young (and again I cannot stop my brain from thinking about how badly I feel for the poor spiders), and having less thickness in the sensitive organ area makes them less of a target for the spiders. Apparently the thin section also helps with precise positioning of eggs in the cramped nests they create.
They are very cool insects, even if you're not into the whole alien abduction thing, though. They are solitary, and each female is in charge of creating her own incubation chambers, meticulously finding wet soil or clay near gardens, streams, or even temporary puddles. She uses her jaws to shape a ball of soil about the size of her head, and flies it back to her chosen spot, often an overhanging surface like one of your home's eaves.
This is the really, really cool part - she can create a strong, tiny vibration with her body that expels the bubbles from the substance. Have you ever watched someone work with pourable resin? They often have to tap the resin to get out tiny bubbles that could ruin their work. She does the same thing, but small.
She shapes the mud into hollow cells, roughly 1 to 2 inches long. A single cell takes about 30 to 40 trips with those little mud balls! Once one tube is finished, she leaves it open, hunts for possibly dozens of spiders to knock out and jam inside, lays a single egg, and seals the chamber entrance with a thicker plug of mud.
These wasps don't play the big numbers game that so many insects do. The females will only create 15 to 30 eggs over the course of her life.
Her adult life is only up to a couple of months long, and once she's flying, she becomes an insect that feeds on pollen to stay alive - reserving the arachnid foods for her offspring only - thus making her a pollinator, so that's, well, that's a life full of very, very hard work.
Look at this terrifying, amazing masterpiece.
Spotted this one at Paula Swanson Forest Preserve.
