Mud Daubers

Whenever I would look up at the ceiling of my porch during the summer, I would see wasp nests: long, hollow cylinders made of mud, dried almost white, placed next to each other like the pipes of an organ. I never thought to question who made these nests until I read Bernd Heinrich’s Summer World: A Season of Bounty. Reading his account of dissecting the nests of the organ pipe mud dauber fascinated me.


This is how the wasps reproduce. They build their pipe-like nests with mud. The nest will be closed at the top but left open at the bottom. The female wasp will find a spider, then sting the spider in order to paralyze it but not kill it. She will take the spider up into the nest. She will stuff several more spiders into the very top of the nest before laying a single egg, then sealing off the compartment with a mud layer. The wasp will then add on to the nest, making it longer, adding more spiders, laying an egg, sealing off the compartment, and continuing. She will add more tubes next to the first and repeat the same process. The egg, when it becomes a larva, will then feed on the comatose spiders as it grows. When the larva has reached a size of about ¾ of an inch, it will spin a cocoon and remain protected inside the nest for the winter. The following summer, the adult mud dauber will emerge from its cocoon and then chew through the mud wall of the nest. Though the wasp larva specializes on spiders, the adult loses its taste for such meat and instead feeds primarily on flower nectar.

As soon as I read Heinrich’s description of the wasps, I immediately went to look on the ceiling of my porch where I had seen the nests so many times before. As I expected, there was a small nest there. While a strong urge exists to take down the nest and dissect it to see the crumpled spiders inside and the wasps growing inside their cocoons, I will leave them be. Maybe in the spring I will pay more attention and look for the female wasps carefully carrying spiders to the porch ceiling.