After chipping ice from the minor glacier that had formed in front of our garage over the last few months and which is now thankfully beginning to melt, I walked out to the big elm tree at the end of the driveway to soak up some spring sunshine. The north side of this big tree was still banked in snow, but the south side was dry and sunlit and warm, with even a few hints of green in the dry thatch covering the bare ground. I poked around in the debris at the base of the trunk, thinking I might turn up something that was alive… Under the very first wood chip I found this bright red beetle, the color of Chinese red lacquer and flat as a fingernail. I quickly retrieved my camera and took a few photographs before it disappeared into the dark crawl spaces under the bark.
It didn’t take long to identify this beetle as a Flat Red Bark Beetle (Cucujus clavipes). The information at bugguide.net suggests its a predator of wood beetles so I’m pleased to have it reside in our old elm, no doubt there’s a good supply of food for it there. I also learned that this particular species is noted for its tolerance to extreme cold temperatures, a feat it accomplishes by producing protein antifreezes, surviving temperatures as low as -150 C in laboratory experiments, which explains why its alive and well so early in the season, mere inches from lingering drifts of snow. A brightly colored and remarkable start to the 2013 insect season.
I spotted this tiny robber fly on a sandy stretch of trail at River Bend Nature Center in Faribault. A very hot day in June, making my way from the Straight River back to my car, I was on the look out for tiger beetles whenever the trail became sandy, but spotted this great little fly instead. The Three-banded Robber Fly is, according to Stephen Marshall’s magnum opus Flies: The Natural History and Diversity of Diptera (2012), the most common Stichopogon in North America, ranging from Canada into Mexico.
These striking black and yellow wasps are recognizable by their unusual length and slenderness, especially the males. For a few weeks in July and August this species was quite abundant and numerous males and females were observed partaking of goldenrod flowers along the Cannon River in Northfield. I found them to be very attractive and took numerous photos. I’ve posted a couple of the best below. Like most wasps, they seldom stay still while feeding, making them a challenge to photograph. If not obstructed in some unfortunate manner by the flower, most of my photos captured a wing or a leg clearly in focus, only rarely did I get more.
This species exhibits extreme dimorphism between the genders. In fact, the males and females are so differently shaped and differently patterned, that they were, early on, thought to be different species. Even the number of bands, from which the species name is derived, is different. These morphological differences didn’t arise solely by chance but are due in part to function. The male, as is the case for most waps, exists only for mating. The female, on the other hand, does most of the work. And her work includes digging, tunneling actually. Thus the stout shape of the female, and the more robust legs. These particular wasps parasitize the grubs of June beetles. To get at these large white grubs, the female digs down to the grub, paralyzes it with a sting, then lays its egg. How the wasp locates the grubs is a bit of a mystery, though it seems likely it would be by scent. After the wasp egg hatches, the larva consumes its host and then pupates, underground where the grub was discovered. The pupae overwinters and emerges the following summer, completing the cycle.
The legs of the long and slender males are yellow and slim, by comparison to the stout, hairy digging tools of the female. Their antennae are long and black, almost decorative. And their yellow abdominal bands are narrow. The males also sport an upturned hook at the end of their abdomen that looks rather wicked; even though the males are unable to sting, this “pseudostinger” is actually used for coupling during mating.
I first learned of this species in Eric Grissell’s Bees, Wasps, and Ants: The Indispensable Role of Hymenoptera in Gardens (Timber Press, 2010). This really is a wonderfully generous introduction to this diverse order of insects, rich in illustrations and information.
After encountering this wasp in the field, I began to look for more information, especially local information that would aid in identification. A vast source of entomological information for Minnesota can be found at the website for the Insects of Cedar Creek, the result of years and years of collecting and identification labor by the late John Haarstad at the University of Minnesota’s Cedar Creek Ecosystem Science Reserve.
Less comprehensive, but fascinating as a historical reference, is my tattered copy of The Hymenoptera of Minnesota by F. L. Washburn. Because so many of the names have changed since its publication in 1919 and because most of the illustrations are borrowed from a natural history survey of Connecticut, this books is only the least bit useful as a guide to identification, unless you already know what you are looking for, for only then does it become interesting to see if this species was reported a century ago. In addition, my particular copy happens to be an interesting association copy, as it is signed by the author, “With the Compliments of the author,” above the embossed name Alvin R. Cahn. Cahn, the previous owner of my copy, turns out to be Dr. A. R. Cahn of the University of Illinois. Sigurd Olson, in a letter to Aldo Leopold dated October 14, 1930, mentions working with Dr. Cahn “on a parisitology [sic] investigation. We spent most of the summer in Ontario. We also made a survey of the birds of the Quetico.”
So, from a few minutes observing and photographing a wasp last summer, not only was I able to learn more about this interesting wasp, but I was also able to follow a book from its beginnings in the hands of the author, given as a gift nearly a full century ago, and placed into the library of a scientist associated with other important naturalists, then from there, through the digital magic of an online used bookstore, the book arrives and falls open upon my writing desk, page 206 to be exact, at the image of Myzine sexcincta, which I believe to be an early psuedonym for the wasp we are considering here.
One wonders where this book might be a hundred years from now? Hard to say. The wasps, however, will still be by the river, prowling goldenrod blooms, hunting subterranean grubs.