Jagged Ambush Bug

It’s been a long week, make that a long month. So many new tasks added to old obligations—construction of a new website for Red Dragonfly Press, publication of several new books (also for the press), new sports teams (for my daughter), and a couple of household wood-working projects—have left little time for visits to even nearby natural areas (let alone time to write about them). Yesterday, however, between fetching my daughter’s bike at the junior high and dinner, I found time for a quick hike at the Cannon River Wilderness Area.

At a pace near to running, it took me nearly fifteen minutes to breach the armpit-high ramparts of horse nettle that crowded the trail through ravine and river bottoms and break through to the good stuff, the wide-open fen and the hillside oak savanna. Catching my breath, I knelt alongside a section of sandy trail. A tiger beetle kicked sand out of a shallow burrow, either hunting or seeking shelter for the night. A bright, black-and-yellow beewolf arrived, its captured prey—a small, metallic bee, barely visible—slung beneath its belly. After remaining motionless for some time, the beewolf flew a few inches into a thicket of grass stems and began to excavate the entrance to its burrow. A satellite fly, gray and rather nondescript, tagged along behind the wasp, no doubt hoping to larviposit on the wasp’s prey before the wasp buries it. (This is probably one of the reasons beewolves rarely set down their prey, even while digging.) I now noticed a second wasp, a thread-waisted wasp. I watched as this wasp searched for a pebble, picked it up in her mandibles, then used it to seal the entrance of her burrow, tamping and pounding with the pebble before dropping it. After a few minutes of kicking sand around and the addition of several more pebbles, the burrow was sealed and camouflaged. The wasp, done with her day’s labors, flew a loose circle around the site, then departed.

Ready to move on, pleased to have been a small part of the landscape the departing wasp had memorized, I stood up. A line encountered recently in a poem by John Fuller came to mind. “But we so easy are still not at our ease.” The poem, ‘Aberporth,’ is a meditation upon a visit to a village on the west coast of Wales. I felt the poet’s admonishment. Here I was, ready to push on, when there was no need to push on. I could have sat down and continued watching over this small patch of sand until it was time to go. Instead, I turned and began to climb the prairie hills toward the oaks above, noting this failure to take my ease, but noting also that the grasses had lost much of their green since my visit earlier in the summer, that the year itself was speeding on as well. A few clumps of Gray Goldenrod still bloomed, adding dots of yellow to the rusty field. Sweet Everlasting bloomed in places as well and added a kind of green, dusty light to the hillside prairie, its pale florets raised like unlit candelabra. Taking a closer look at one of these flowers, I noticed a very strange bug.

Jagged Ambush Bug – Northfield, Minnesota – September 18, 2014
Jagged Ambush Bug – Northfield, Minnesota – September 18, 2014

Disruptively colored, its abdomen indented and spiky, this bug would be nearly invisible on a goldenrod flower, but on the white, bud-like everlasting flower, it stood out (instead of blending in). Still it was so small I couldn’t really appreciate how odd-looking it really was. Later, when I enlarged the photos, a chimera-like creature appeared on the computer screen, part Musk Ox, part mantid. Given such a fierce aspect at larger-than-life sizes—just look at those fiery eyes!—it’s best that its true-to-life dimensions remain at less than a centimeter in length.

This strange creature is a Jagged Ambush Bug. An apt name, I think, considering it’s basically a living trap for other insects attracted to the flowers on which it waits. Supposedly it’s even capable of capturing prey larger than itself. Fair warning, I guess, to those of us who wish to stop and smell the flowers, who insist on sticking our noses into the blooms.

Is it a wasp? Is it an ant? No it’s a…

Broad-headed bug (Alydus eurinus). These bugs are common in goldenrod fields in autumn. When I first saw this insect, moving about the grass stems and goldenrod, flicking its wings, I followed after it because I thought it was a spider wasp. It was only when it stopped and I got a good close look at it that I discovered I’d been fooled by an outstanding mimic. Not only does the adult bug convincingly mimic black spider-hunting wasps, the younger nymphs of these bugs even more convincingly imitate ants! This profile, I surmise, must provide some level of protection as they sit and siphon off plant sap with that long, needle-like drinking straw of a mouth. Should you consider collecting one, be forewarned that they also protect themselves by emitting foul smelling pheromones, well in league with the stink bugs.

Broad-headed Bug (Alydus eurinus)
Lashbrook Park, Northfield
September 16, 2012