The Way of the Wasp (or: Cavorting with Caterpillars)

She is now as lovely as I have ever seen her: long-legged and elegant, deep red and black—a beauty, by any acceptable definition. She crouches on the rim of a borrowed glass jar and gazes with the depthless black eyes that fill half of her sharply pointed, nearly feline face. Her wings are sooty, coal-black, and pressed tight against her abdomen. Her segments are clean, her reflexes quick, and she stares at me through the glass as if obstinately, wasp-waisted and dignified and so tiny that she could rest comfortably on my fingertip (if only I were convinced that she wouldn't turn her stinger on me). She spreads her wings ever so slightly to groom, then returns, legs splayed and antennae still, to her previous, stoic attitude, lapping casually at sugar water as if it is her birthright.

Of course, I haven't the slightest idea what she eats, beyond plain sugar water. I have offered her everything from tofu to dog food to mango, plain and sugar water, jams, even the odd crumb of cheese (I suspected it would not tempt her, but my dear, long-lived Dermestes lardarius, Morton, has been enthusiastic enough). The literature is, maddeningly and unusually, useless. She is a member of the species Trogus pennator—an Ichneumon wasp—and every last written word on that species seems to refer only to the larval stage, or at least the host-finding mechanisms of the adult female: the “interesting part”.

I suppose this story really began months ago, in the deep and barbarian wilderness of Kickapoo State Park, where I was gratified to come upon the host plants of several young swallowtail caterpillars, many in their first or second instars (this is wildly exciting for me, because I have a long tradition of hand-raising arthropods, or at least attempting to befriend those that occur domestically, from the earliest, pleasantly fuzzy Arctiid caterpillars and isopods of my youth to regal, if mangled, Eleanor, an injured Chinese mantis, and her successor, the cat-like Seymour, from the waning Monarch, Jane, to the caterpillar Buckeye, William, who spread his wings just as the first autumn breezes blew). I already had several lepidopterans of different families at home—William had just pupated, and I had five larval Arctiids eagerly stripping my lawn of clover and plantain, but the swallowtails were irresistible. There were many, and, perhaps proudly, I collected four of the youngest (Rosalind waved her osmeterium threateningly; perhaps it was a true warning that I did not then have the wisdom to heed). The first swallowtail instars have a terrible habit of looking much the same (they are bird dropping mimics), and correct identification is essential, since even the most closely related of butterflies favour different food plants. Still, I returned home that day with the christened Isabella, Eirian, Marisol, and Rosalind (well, and Hildegarde the Membracid, although she is less relevant to this tale) in tow, and after some time comparing pictures, it was decided that Marisol and Rosalind were Eastern Tiger Swallowtails (Papilio glaucus), who would eat tulip tree leaves, and that Isabella and Eirian were Black Swallowtails (Papilio polyxenes), who might eat either fennel or dill. With that settled, I cheerfully wandered out to procure their preferred food items and fixings for a comfortable habitat, hardly considering, never imagining the horrors to come.

The first was poor Rosalind, who expired prematurely, so unlike her Shakespearean namesake. She was never quite as hefty as her age-mates, and I suspect now that she died of some variety of virus; it was pure luck that I recognised her illness prior to its spread to the others and isolated her. The next was Fairfax, an Arctiid whom I had collected several weeks prior, who died unexpectedly, and, upon preservation in alcohol, revealed the two larval parasites that had killed an otherwise energetic and hungry caterpillar. It was the first time I had seen such a thing in person, and I admit to fascination and a fair amount of morbid excitement, even as I mourned poor Fairfax. But time passed, and the others pupated. Some, like William, emerged before the winter, but the majority overwintered, and most of them remain with me still, awaiting the spring. I was rapt with fascination, I admit, especially at the transformation of the swallowtails. From bird dropping mimics they diverged, and Isabella and Eirian grew lovely and striped down, in black and green and yellow, while Marisol went the way that Rosalind had missed, forming bright eyespots and a rosebud-pink head, before going completely brown prior to pupation. They pupated by cradling themselves with strands of silk, nearly upright against the branch of choice, and shaking, squirming out of their last caterpillar skin. When the three had finished, I took their twigs from their jars and laid them safely away to overwinter in peace. Alas, 'twas not to be.

When I discovered Marisol's chrysalis empty in late January, I admit to confusion; the tiny hole through the woody skin was not typical of the butterfly's emergence, and there was no evidence of a large-winged swallowtail anywhere in the house, not accounting for the strangeness of her having emerged prematurely anyway. I was disappointed, I admit; I had been looking forward to her emergence in the spring, and now I had only Isabella and Eirian of the original swallowtails. Perhaps.

I found Kitty about a week ago, buzzing loudly in my lamp, fruitlessly trying to find a way out. I offered her an index card to climb on, and when I pulled her out, I was truthfully confused. I knew her species, I'd seen her brethren before, but only ever during the warmer months, never in bitterly cold early February. I knew her to be a member of the family Ichneumonidae, but beyond that, I had no surety of her identity. I gave her a paper towel soaked with sugar water, and set her away in a Petri dish overnight, musing on her strange and sudden appearance as I turned out the light to quiet her incessant buzzing. The next day, however, shed some light on her character, by way of the nicknamed Giant Book in the biology lab; after lingering over the lovely photographs of jewel-bright beetles, I turned to the Hymenopterans and in minutes had a match for my renegade friend—of course, Trogus pennator, a beautiful wasp, sure, but more importantly, a swallowtail parasite. I left Kitty (or “Shirley”, to some) safe and warm in the lab, housed in said borrowed jar, with a promise that I would return the next day with some manner of potential foodstuff for her sampling pleasure. I hurried home as quickly as I could jump over piles of snow, eager for closure to this mystery.

It was with a certain heaviness that I pushed open the door to my bedroom, walked to the bookcase, and picked up the chrysalis of the late Isabella. The irregular hole chewed through its surface momentarily chilled me, and I put it back down, turning away, mourning my Isabella and the chance to see her fly. I knew now, also, what had happened to Marisol, though I never did find her parasite. And yet, it was with excitement that I collected a number of varied food items to offer to Kitty the next day (I have no evidence that she ate any of it, but one tries, and the weather is too harsh to simply let her go). Either way, I mix sugar water for Kitty with the same enthusiasm that I searched for Isabella's fennel and dill. Perhaps my affections are fair-weather only, but I cannot resent Kitty for the death of Isabella. I suppose Isabella never really was, not the singular Isabella that I knew, and in some twisted way, the chrysalis that Kitty chewed her way out of really was her own. It is chilling and strange to we who like to find morals in everything, this thankless use of a true child's living body for food and shelter. Charles Darwin (a far, far wiser and more eloquent man than I) said once in a letter, “I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars...”—well, let words such as these be the end of a wildly prolonged and blatantly entomophilic post.