On a morning in late July, the songs and raucous calls of Blue Jays, Cardinals, and Carolina Wrens were joined by another sound—an intermittent, insistent buzzing. It seemed to be an angry wasp, an unwelcome distraction as I worked facing the large east-facing picture window. Orchids line the window ledge, their pots and foliage blocking my view of the lower edge where I assumed the insect was trapped.
During one of the silences, I approached with a cup and stiff sheet of paper, prepared to capture the intruder and carry it outdoors. Peering cautiously around the orchid pots, I saw nothing. Then the buzzing resumed. Following the sound, I looked more carefully and discovered something entirely unexpected: affixed to the outside edge of the window was a long tan column of dried earth.
It looked geological—a miniature formation of hardened sediment affixed to the corner of painted wood and glass. Its surface was ridged and corrugated, each irregular band recording some earlier act of construction. At its lower end appeared the architect: a large, lustrous black wasp.
I discovered the wasp’s identity also explained both the strange earthen structure and that surprisingly loud buzz: this was an organ-pipe mud dauber, Trypoxylon politum. The species occurs through much of eastern North America and is the largest member of its genus in our region.
The name is wonderfully descriptive. The female constructs elongated tubes of mud side by side against sheltered walls, bridges, rock faces and buildings. A completed group resembles the vertical pipes of an old church organ. What I had initially taken for a crude column of dirt was, in fact, architecture.
The wasp itself has an austere beauty. Its body is predominantly polished black, sometimes seeming almost blue-black as sunlight catches the wings and exoskeleton. The abdomen is extraordinarily slender near its base before widening toward the end, giving the insect a delicate, elongated silhouette. Long black legs hang beneath it, with pale markings on portions of the hind feet. In my photographs the wings sometimes flash an unexpected smoky violet-blue, while the legs grasp the painted window frame beside the ocher-colored mud. Against that earthy structure the wasp looks almost metallic.
Yet the formidable appearance is misleading. Unlike yellowjackets and other colonial wasps, the organ-pipe mud dauber is essentially solitary. There is no queen commanding a workforce and no populous colony ready to defend the nest. A female constructs and provisions her own nest, and solitary wasps consequently tend to be much less defensive than social species.
But Trypoxylon politum adds a fascinating complication to the word solitary.
A male may remain at the nest while his mate is away. He guards its entrance against intruders—including parasitic insects and rival males—and may produce a conspicuous buzzing when something approaches. That behavior makes me reconsider my first encounter. The creature I heard behind the orchids was not an insect frantically trapped indoors at all. The window glass separated us. I was inside; the wasp was outside, stationed beside its earthen fortress. What sounded to me like anger was vigilance, though I also observed similar buzzing as the female shaped each ball of mud.
The female performs the more astonishing work. She gathers wet mud and carries it repeatedly to the nest, gradually extending a tube. Inside she creates a succession of chambers. Then she becomes a hunter.
Her quarry is spiders.
She captures and paralyzes them, carrying them back to the nest and packing several into each cell—reported numbers range from about three to eighteen spiders with the fertilized female eggs better provisioned. Upon this living but immobilized store of food she lays an egg and seals the chamber with mud. The larva that hatches within has a private larder of fresh prey. Another chamber follows, and another, until the peculiar earthen pipe becomes a nursery divided into hidden rooms.
There is something almost unsettling in that knowledge. Within the rough tan structure, a nest, on our window frame lie spiders gathered from our garden, each incorporated into the reproductive cycle of another animal. Predator becomes provision; mud becomes shelter; a few inches of ordinary window trim become an ecosystem.
That is what held my attention long after the original buzzing ceased. I had sat only a few feet away, day after day, unaware that another creature was carrying out an intricate sequence of hunting, construction, mating and parental investment on the opposite side of the glass.
The window had seemed a boundary between our house and the natural world. The organ-pipe mud dauber revealed it to be something else: a place where the two worlds meet.
And all it took for me to notice was a buzz.
Michael Stephen Wills Photography 