Mothing

Blurry Chocolate Angle
Blurry Chocolate Angle

“Chancing to take a memorable walk by moonlight some years ago, I resolved to take more such walks, and make acquaintance with another side of Nature.” – Henry David Thoreau

The mothing began without intention, the frontdoor light left on by chance. Going out well after dark with the dog, I noticed several moths on the side of the house near the light and had the wherewithal to capture several of them. Thereafter, following this serendipitous beginning, the light was left on deliberately, becoming something of a nightly ritual throughout the autumn months.

Not long after the mothing commenced, I purchased a copy of Discovering Moths: Nighttime Jewels in Your Own Backyard by John Himmelman. I enjoyed this book immensely, reading it cover-to-cover in a matter of days. Himmelmann does a really great job of passing along his enthusiasm for moths. The line drawings, the mini-biographies of Lepidopterists and other mothing folk, the seasonal presentation of the mothing year, and the color plates provided the thorough introduction to this group of insects that I needed. And it was in this book, in its discussion of mothing equipment, that I came upon the suggestion of using a bug-zapper as a mothing light.

Now, the bug zapper is truly a repugnant invention. The one and only insect pest it purports to annihilate, the mosquito, is not attracted to light. What smokes and settles in a heap beneath the powered-up machine is a wide variety of beneficial insects, non-biting midges and moths making up a large percentage of the kills. The fact that they are marketed nowadays with chemical lures to attract mosquitoes I take to be an admission of their ineffectualness. In my opinion, bug zappers should be banned and taken off the market. A consequence of their ineffectualness, however, is that used ones are available very cheap. And, using a few simple tools and some electrical tape, the high-voltage grid can be disarmed and the remaining UV light repurposed as a moth light.

This new set up, the now-benign bug zapper hung at the top of our white garage door, provided a marked increase in the attendance of moths. Once or twice a week, if the weather cooperated, I’d set up the light, turn it on, and wait. I’d go out at dusk and then a number of times after that, eventually turning the light off at some point well after midnight to let the moths go about their business…and not rouse too much curiosity about my behavior among our neighbors.

Vagabond Crambus Moth
Vagabond Crambus Moth

My daughter took to helping me (any excuse to stay up late…right!) and became very adept at catching the moths. Most of the moths were small and could be captured in vials. After capture, the moths went into the refrigerator for the night. In the morning, once the sun was up, they were photographed and released. Usually, the refrigerated moths would sit for some time while they warmed up, allowing me to take dozens of photos. The smaller the moth the less time you have—the ratio of surface area to body volume playing a part in how fast they warmed. The micro moths flew almost as soon as I popped the top on the plastic vial, so I don’t have many successful photos of these tiny moths. My daughter also enjoys all the curious names that moths have been given, as do I. Here’s a sampling: The Wedgeling, The Asteroid, The Deceptive Snout, The Ambiguous Moth, Blurry Chocolate Angle, Hitched Arches, The White Speck.

Our shiny Peterson Guide to moths, purchased in 2012 and barely used, was finally getting some use. At first, with little knowledge whatsoever about moths, the number and variety was simply bewildering. It had taken me several years to get familiar with the hundred or so local dragonflies, the local moths, on the other hand, numbered in the thousands! Himmelman’s book provided an in. And two online resources, bugguide.net and the moth photographers website, provided the added information and assistance needed to begin making identifications of some of the moths. A look at all the moths captured (nearly 250 photos) can be had by visiting my Flickr site and looking at the moth set. Many remain unidentified, and many have question marks appended to tentative identifications, so please feel free to leave corrections or identification suggestions.

Wavy-Lined Heterocampa Moth
Wavy-Lined Heterocampa Moth

A third excellent online resource is the Butterflies and Moths of North America website (BAMONA). The BAMONA website checklist for Rice County lists (at the time of this post) only eleven species. Over a period of three months, late in the year, missing the spring species and many of the summer species, I collected and photographed well over seventy different kinds of moths just in our driveway. Eventually, as time permits, I’ll submit my sightings to BAMONA. That there is a long way to go in documenting the moths of Rice County can be demonstrated by looking at the numbers of species for a better surveyed county. For instance, Wright County, northwest of Rice County, has 280 species on its list.

So, with more work to do and more discoveries to make, I’m looking forward to spring, and the commencement of a new mothing season. I’m also hoping to graduate to the more traditional white sheet this spring. And, if time permits, maybe try some other locations around the state. Who knows, I might even organize a mothing event for National Moth Week, July 19 – 27, 2014. Yes, there’s a national moth week…how cool is that!

White-lined Sphinx Moth
White-lined Sphinx Moth

Resources & Links

David Beadle & Seabrooke Leckie. Peterson Field Guide to Moths of Northeastern North America. Houghton Mifflin Harcourt. 2012.

John Himmelman. Discovering Moths: Nighttime Jewels in Your Own Backyard. Down East Books. 2002.

Moth Photographers Group

bugguide.net

Butterflies and Moths of North America

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Compost Fly

Ptecticus trivittatus
Ptecticus trivittatus

I captured this fly after dark, at our front porch light in early August, 2013. After capture, the fly spent the night in a vial in our refrigerator. The following morning as soon as there was plenty of light, I released it. Being chilled, it stuck around long enough for a few photographs.

Looking at this fly, and the photographs of the fly, I was immediately struck by it’s colors, the translucent greens and ambers, its size and shape, the venation and rippling look of flowing water in the wings. Only later could I identify it as a Yellow Soldier Fly, Ptecticus trivittatus. This fly, common in eastern North America, is most often observed near compost piles and fermenting fruit, so why was it hanging around the porch light after dark? Those big compound eyes and the pronounced ocelli indicate it’s well adapted to low light conditions; maybe it’s just that the earthy wine these flies seek, decanted from decaying lawn clippings and fallen fruit, is better in the shade. My subsequent encounters with this species placed it at our compost pile, but it also showed up again after dark, at the mothing light on several occasions.

Ptecticus trivittatus
Ptecticus trivittatus

Looking for more information about the fly on the web, I came across a short note in the journal Psyche by Philip Rau, author (along with his wife Nellie) of Wasp Studies Afield (1918). Here are a few passages in summation of our compost fly, in Rau’s characteristic flouncy style, written around 1930, in or near Kirkwood, Missouri:

“…these attractive greenish-colored flies were seen hovering in courtship dance above garbage heaps on the rear of a lot… To say that they dance incessantly is not wholly true for individuals often leave the throng to rest on a tin-can or bottle or cantaloupe skin… indeed, it’s a pretty sight to see a flock of these flies moving in a horizontal plane in more-or-less irregular circles and in figure eights just an inch or two above the mass of multi-colored refuse.”

Ptecticus trivittatus (total length=14mm)
Ptecticus trivittatus (total length=14mm)

Resources

Bugguide page for Ptecticus trivittatus.

Eric R. Eaton. Kaufman Field Guide to Insects of North America. Houghton Mifflin Harcourt. 2007.

Phil Rau. Notes on the Courtship and Mating of the Fly, Ptecticus trivittatus Say. Psyche 44:141-142, 1937.

Trap Nest: Part Three

Trap Nest: Part Three

An examination of the open trap nest revealed four occupied cells and one empty cell, a vestibular space between the nest plug and the occupied cells. Three of the occupied cells contained potter wasp larvae, the fourth, the one closest to the entrance, did not. It held, apparently, the remains of the original provisioning, as if the potter wasp egg never hatched. Placing the nest and this suspect cell under the microscope, I discovered two tiny wasps (both dead), three tiny cocoons (one still full), and a bunch of mummified caterpillars. Something had obviously gone wrong in this cell.

Trap nest cell contents
Trap nest cell contents

The cell in question, being the closest to the entrance, was the last to be provisioned. It appears, bad luck for the provisioning wasp, that one of the caterpillars captured and placed in the cell must have been secreting a number of parasitoid wasp larvae. Like the clever Greeks in the Illiad, these wasp larvae emerged from their caterpillar host (the substitute for the Trojan Horse in this metaphor) at some point after being sealed into the cell. Unlike the successful Greeks, these stowaways perished. Not having the mandibles or the mud-dissolving spit required to breach the mud partitions, they died, immured in the dark. In describing this, I feel other literary echoes, namely the horror story The Cask of Amontillado by Edgar Allan Poe. Of course the fate of the caterpillars in this cell is hardly more disturbing than the fate of the other caterpillars stung into paralysis, then devoured alive.

These wasps really were small, just a couple millimeters in length, no larger than an Argentine Ant, that common pillager of kitchen sugar. The wing venation indicated the wasps were of the family Braconidae, a large family of parasitoids with more than 1,700 species in North America. Interestingly enough, some braconids have been used as biological agents in the control of agricultural pests, pests such as the Cabbage Butterfly. Many species are colored black and red or black and orange. Since βρακον is Greek for breeches (or pants in a less stilted dictionary) I wonder if the brightly colored hind legs resulted in the family name or if it’s those swollen thighs, the coxa, that gives the family its name? As far as I could determine, these particular wasps belong to the family Agathidinae, though in consulting a recent key to the Agathindinae I couldn’t make it past the first binomial because my microscope isn’t powerful enough to examine the shape of the foreclaws, so I don’t even have a guess at the species.

Braconid wasp
Braconid wasp

While the Braconidae are interesting in their own right, this failed cell also provided an opportunity to look over the provisions. Seven small green caterpillars, all probably of the same species (no prolegs on A3, patterned prothoracic shield) were preserved. According to both Cooper and Krombein, Ancistrocerus antilope (the likely provisioner of this nest), stuffs its nest full of small caterpillars, most often the tiny larvae of micro moths—the crambid moths, the twirler moths, the concealer moths—and that appears to be the case here. My best guess, after an hour browsing bugguide, would be a Tortricid moth larvae (Tortricidae, tribe Archipini; possibly Choristoneura sp. which seemed to have a very similar prothoracic shield). The cell also contained a different species of caterpillar, 2 to 3 times as large as the others (prolegs on A3-A6, no prothoracic shield). It seems likely that this caterpillar hosted the wasps.

Krombein also reported that Ancistrocerus antilope provisioned its cells, on average, with 3 to 10 larvae, usually of a single species, and usually of early instars, the selection of early instars no doubt lowering the likelihood of interring a larvae containing parasitoids. And Krombein, out of thousands of trap nests examined, reported braconids in just two! I feel fortunate to have happened upon this complication so early in my trap nesting career.

The nest, reassembled, has been overwintering on a frosty window sill in my cold, corner office, sitting alongside plastic cups with dragonfly nymphs, other containers filled with Lepidoptera cocoons, and several heaps of gathered plant galls. It’s a nice place to sit on a cold winter day, one large creature among numerous little creatures, all of us biding our time, preparing for warmer weather.

If I hadn’t set out this trap, I wouldn’t have learned of these wasps, or known about their presence in our back yard. I wonder, often, about how few people know or care about these small happenings. I worry, just as often, about my own lack of understanding, the little I really know about the complexities of even my backyard, let alone the larger world. And I suspect, more and more, that it’s simply a failing of patience and of imagination if, for instance, a certain moth caterpillar runs rampant in our gardens and we reach for insecticides, not trusting the unseen checks to their population provided by wasps and other predators.

I think the tension, here, is between what we manage and what we don’t manage. What escapes our hand widens and grows wild. This is not pristine wild, but salvaged wild, the wild that creeps back over the land, resettling the unweeded margins, homesteading the fallow flower pots, mining the messy understory and the fetid margins of the compost. When I see weeds I see hope; and when I see unmown, unsprayed lawns I see progress being made.

Resources:

Cooper, K.W. 1953. Biology of eumenine wasps. I. the ecology, predation and competition of Ancistrocerus antilope (Panzer). Trans. Am. Ent. Soc.79: 13-35.

Evans, H. E. 1963. Wasp Farm. New York: Natural History Press, Doubleday.

Krombein, K.V. 1967. Trap-nesting wasps and bees: life histories, nests, and associates. Smithsonian Press, Washington D.C. vi + 570 pp.