Humane Gardener

The mother asks for nothing but a little clay and a few spiders. The father protects the kids and helps sculpt the nest. Neither has any interest in stinging people. What could be more fun than watching these dedicated parents and natural architects?

mama carrying mudball — A mama organ pipe mud dauber wasp lifts off from her quarry, a muddy patch near our pond, to carry a clay ball back to her nesting site.

Where are all the butterflies? What happened to the summer rains? As drought looms over us like a wilted cloud and the butterfly season feels vaguely doomed, it’s probably natural that we tend to notice only what’s missing. But look a little closer and listen carefully, and life makes itself known in the cracks and crevices, under the logs and leaves, and—most recently in our habitat—even in the mud.

Last week, instead of packing masks and hand sanitizer for our annual trip to the beach, my husband and I chose a safer vacation spot: a bench by our new pond. Though I craved the sand between my toes and the salty air in my nose, the tiny oasis offered something else: unprecedented frog-watching opportunities, dragonfly sightings, a face-to-face encounter with a scarlet tanager, and conversations with my favorite chipmunk as he wove in and out of the stones.

And while I longed to hear the sea cradling the shoreline, if I’d been away from home, I would have missed out on a new sound: an intense drilling at the pond’s edge. At first it reminded me of buzz pollination, which occurs when native bees contract their flight muscles and vibrate them at a high frequency to dislodge pollen from flowers. But a closer look revealed that these sounds of industry were coming from a different kind of animal, one of nature’s most diminutive architects:

She was an organ pipe mud dauber wasp, and when I hit the books to learn more about her, I realized my mental comparison to buzz pollination was no coincidence. The wasp was using a similar mechanism to mine the soil: “Mud daubers become musical masons as they work the mud from which they build their nests,” writes author and biologist Justin Schmidt in The Sting of the Wild. “The ‘musical noise’ … is generated by contracting the wasp’s thoracic flight muscles, thereby vibrating the head and mandibles while emitting a high-pitched sound.”

After forming a mudball, the subject of my fascination zoomed off with her building materials, returning a few minutes later for more. When Will came to join me on the bench, he was just as mesmerized by the invertebrate excavator and began taking pictures too. “Do you think she’s building a nest under the deck?” he wondered aloud. “I’ll go take a look!”

Only a few moments passed before Will’s triumphant return to the pond. Sure enough, he reported, our little friend was making a nest right in full view. It was an activity we’d end up watching off and on for days:

For as long as I can remember, organ pipe mud dauber wasp nests have graced the deck beams above the entrance to our basement. But though I’ve taken plenty of pictures in the hopes of changing people’s minds about these unassuming creatures, I’d never witnessed the nest-building process. As the mother creates cells for eggs within the tube, she also catches and paralyzes spiders, stuffing them into each cell so her wasp babies will have something to eat when they hatch.

Watching her stretch the mud balls out, elongating her organ pipe nest a little more with each trip back from the pond, I admired the hard-working mama’s artistry. I also started to notice something else: the head of another wasp peeking out of the tube, sometimes quickly retreating and sometimes chasing away other wasps. Mud dauber wasps are solitary—one of the reasons they’re gentle around people, since they don’t have colonies to defend. So who, I wondered, was the second wasp hanging around the nest?

Through further reading, I Iearned that male organ pipe mud dauber wasps are dedicated dads. They stay in the nest to guard the larvae while the mom collects building materials. Sometimes males even help with construction, but their main role is protection from numerous threats: Without their vigilance, other mud dauber wasps might try to claim the nest as their own. Predators and parasites, including flies and other wasp species, are also among the dangers.

It wasn’t always possible for me to tell who was coming and going, and sometimes it seemed there might be a second female or male trying to commandeer the hard work of the original parents. But one kind of interloper was unmistakable: cuckoo wasps looking to parasitize the organ pipe nests by laying their own eggs in them.

They weren’t succeeding, at least not while I watched. But if they do eventually manage to sneak in, their cuckoo wasp babies will hatch and devour at least some of the contents of the nest. Depending on the species of cuckoo wasp, they might eat the spidery snacks, thus starving the mud dauber larvae, or they might eat the mud dauber wasp larvae directly, or both.

This may not seem like a neighborly way to raise a family, but I couldn’t help feeling sorry for the cuckoo wasps anyway; it must be difficult to have to engage in such covert operations just to find a home for your young. I couldn’t ponder the odd behaviors wrought by evolution for long, though. Soon enough, another kind of wasp came into view, and this one was carrying a heavy load, a hapless spider destined to become a meal:

My heart went out to the little spider even as I reasoned that wasps need to eat too. Once again, the insects had no time for such sentiments. During the brief moment when I’d turned away to record the spider’s sad demise, one of his behemoth cousins came to level the playing field, parking herself right underneath the mud dauber wasp nest.

She stayed still for a long time, and if she eventually caught her quarry, I wasn’t around to see it. I suspect our wasp family survived her presence, though. Just a few days later, the wasps have laid down a second pipe, indicating they are still hard at work on providing for the next generation:

Image of Organ pipe mud dauber wasp nests under deck — A few inches to the right of the third crossbeam, on the wood right next to the house, the new parents made a second organ pipe over the past few days. We’ve coexisted peacefully with these nests under the deck for 20 years.

Though we won’t experience the splendor of the high seas or low tides this year, there is high drama in low places right here at home, as we watch many kinds of animals feeding, teaching and fighting to protect their young. I’m happy to see the butterflies slowly trickling in above us on their way to the wildflowers now, and I was delighted to welcome the monarch who landed on my shoulder today. But I’ll also continue to appreciate what’s happening at our feet, keeping the soil by the pond moistened not just for puddling butterflies but for all the mother wasps who need little more than mud and water to craft a safe home.