Arachnid Mummies Daubed in my Wall

Yellow or Black Dirt Dauber Nest

We recently bought a house built in 1931 located on a quiet street at the edge of Fayetteville. The house was cheap and needed a lot of work. We started by ripping off the musty wallpaper and moldy carpet. Underneath, the walls told stories. One room was a hot pink template covered in teenage graffiti. The living room had old fake wood paneling on the walls, which we tore down just other day. The open cavities in between the studs were full of ancient spider webs and dirt dauber nests. I carefully took one dirt dauber nest out of the wall for examination.

Dirt or mud daubers are often feared a much as hornets or red wasps, but daubers lack aggression and rarely sting people, even though they build their nests in and around houses. Female dirt daubers construct clusters of chambers out of clay. She rolls clay into a ball and flies with it to the nest sight. Carefully she daubers the clay balls together one at a time until most of one chamber is built. Then she hunts for spiders while the male protects the nest from parasitic wasps looking for a place to their lay eggs.

When the female dauber finds a spider, the dirt dauber must fly down and sting the arachnid without getting stuck in its web. The poison in the dauber's sting does not kill its prey, instead the spider is paralyzed. The dauber collects these live spiders and packs them into the chamber. When it is full, she lays an egg inside and encloses the chamber with a bit more mud. When the egg hatches, the larva, a grub-like creature, eats the paralyzed spiders as it grows. Since the spiders are not dead, they don’t rot. Eventually the larva makes a cocoon, and transforms into an adult mud dauber which breaks out of the nest and searches for a mate to start the process again.

With careful precision, I cut open the ancient nest I had found encapsulated in the old wall. Inside spiders lay like mummies. The abdomens of many were hallowed out; they had been eaten alive. Looking at these arachnid skeletons, I saw spiders from a new perspective. Often I mistakenly assume these carnivorous creatures are at the top of the arthropod food chain. But alas, there is yet I higher bug. Don’t forget, there is always a higher bug!

Ancient paralyzed spiders in a dirt dauber nest