Friday, September 1, 2017

In which I join a Potter Wasp for lunch

We were grateful for the light breeze that sent our patio umbrella flapping, and also for the shade of said umbrella. Somehow we'd chosen what may be the last hot day of summer to go on our annual bike adventure. Eighty degrees and humid over the course of almost twenty miles was sufficient to get the sweat dripping.

It was worth it, though to swoop through the hilly backroads of the Chequamegon National Forest and emerge from the woods at the Farmstead Creamery and Café on the North Star Homestead Farm. Run by a family of strong and talented women, this diversified network of pasture-raised poultry, sheep, and hogs, as well as raised-bed gardens, a high-tech aquaponics system, and permaculture practices, draws lots of hungry admirers.

An outside table with a big umbrella was the perfect place to relax and wait for our home-cooked, local, organic, delicious lunch to arrive. And then, my day got even better.

Movement spotted out of the corner of my eye resolved into a small wasp carrying a green caterpillar. The caterpillar was about the size and diameter of the wasp's own body (1/2 inch by 1/8 inch), but neither seemed to be struggling. The wasp hovered and wandered for a bit in the vicinity of the shade umbrella's crank arm. Finally it landed, and started the slow process of dragging the limp larva into the mud-caked hole in the end of the crank's handle!

As you can imagine, I was pretty excited. While watching this drama, one of the farmers popped out of the Café carrying our plates of food. Naturally, I waylaid him at the table and made him check out the action. I'm not sure he knew what to make of it-or my enthusiasm-at first, but I think I convinced him to be impressed before he went back inside.

After a few minutes, the last segment of green disappeared. Then, suddenly, the wasp backed out of the hole and flew off!

Over the course of lunch, I had to put down my delicious pesto-melt sandwich several times to capture photos of the wasp landing, and its black-and-yellow-striped abdomen circling all around just inside the entrance to the little mud and metal nest. It brought a load of something each time, but never another caterpillar while we watched. The bundles clasped in its forelegs were dark and amorphous.

After our amazing dessert of sheep's milk gelato (blueberry fudge flavor-yum!), we started the long, hot ride home.

Using an amazing website called, which is hosted by the Iowa State University Department of Entomology, I posted my blurry cell phone photos for identification help. Within hours, a contributing editor with experience in wasps replied with a name: Eumeninae.

Now, understandably, my fuzzy photos don't give enough information to identify this wasp to species. Even so, just knowing the subfamily it's in gives me some clues to its lifestyle. Also known as potter wasps, this diverse group of solitary wasps use mud to create a variety of nest shapes. Some potter wasps make round-bottomed, narrow-necked nests that look exactly like traditional pots. Legend has it that some Native Americans based their pottery designs on these nests.

Other potter wasps make their nests in pre-existing cavities, like the end of a crank handle on a patio umbrella, or any other hollow or crevice they can find. Also called mason wasps, they use mud or sand for construction.

Inside each nest chamber she constructs, the female wasp lays just one egg, and then goes about the business of storing up baby food. Adult potter wasps eat nectar, but for their growing offspring, they collect moth larvae like the tiny green caterpillar I witnessed going to its death. Beetle larvae and spiders may meet a similar demise. In any case, the adult delivers a paralyzing sting to the prey, but the toxin does not kill them. Dead larva would soon decompose. These stay fresh but immobile, ready for the hungry wasp larva to hatch and start feasting.

It might take anywhere from a few weeks to a year for the larva to pupate, metamorphose, and mature. Then, with powerful jaws, the adult wasp breaks open its earthen nursery and emerges to find a mate.
Although I can't be certain that this Euodynernus wasp is the same species as the one I saw, the irregularly-spaced yellow stripes match my photos. Adult potter wasps feed on nectar and pollen. Photo by Bruce Marlin, Wikimedia Commons.
While watching this black-and-yellow lady go about her business, two main thoughts were swirling through my head. The first was the importance of a healthy insect population on an organic farm. Using pesticides would have killed off this predator, removing a completely free source of caterpillar control. The North Star Farmstead is doing it right. The second thought was about just how tightly packed this world is with LIFE. Every nook, every cranny, every surface, is someone's home. Experiences like this make me especially glad that it's my home, too.

Special Note: Emily's book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at  Listen to the podcast at

For 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new exhibit: "Better Together--Celebrating a Natural Community" is now open!

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