Invasion of the longhorns

My, what a big set of antennae you've got, Ms. Beetle! Elegant and outrageous, a Dectes texanus longhorned beetle explores a leaf in Adams County. I made this image on August 27, 2011. This rather amazing bug has no common name, rather amazingly. It and its closely related ilk are collectively known as flat-faced longhorns.

Over 20,000 species of longhorned beetles have been named worldwide, and there are probably thousands of species yet to be described. The adults are often fabulous looking creatures, with their incredibly long antennae perhaps the most distinctive feature. When a longhorn alights near someone, they're sure to notice it. The problem is, for longhorned beetle enthusiasts, they're mostly out of sight for much of the year. Nearly all of the species spend much of their life cycle as a grub, happily boring through the inner tissues of plants. You'll never, or at least hardly ever, see that stage. But for an all too brief glorious period, the adults emerge from the wood and take flight as they seek mates and sustenance from flower nectar.

Most years, I'm lucky to run across a small handful of longhorned beetles, if that. So it was with a fair bit of shock and joy that I glanced down into the snakeroot on a recent field trip in southern Ohio and saw this magnificent beast. It is a six-banded longhorn beetle, Dryobius sexnotatus, and it is said to be rather rare.

This is a big beetle, probably over an inch long, and you wouldn't have missed it. Bold yellow and black patterning certainly doesn't make it blend with its surroundings, and it seems likely that the six-banded longhorn is a hornet mimic. Lots of would-be predators will leave an insect with this sort of warning coloration and patterning well enough alone.

Our discovery of this beetle came at the conclusion of a long, very hot field day, and that feeble excuse is my rationale for not making better photos. The beetle was very active, and in dense shade, hence the lack of crispness. I should have taken the time to employ some tricks of the trade to get better images.

The six-banded longhorn rapidly scales a sugar maple, which is said to be one of its host trees, along with beech and elm. There were plenty of these trees in the immediate vicinity. Six-banded longhorns have generated more than the average interest among longhorned beetle enthusiasts because they are thought to be rare. Some authorities state that they are typically associated with older-growth forests, but this one wasn't - it was in a rather typical area of varied tree succession, with only patches of larger older woods.

A few days back, a friend posted this photo on Facebook, asking for an identification. The beetle had by turns horrified and fascinated the people who discovered it on this poolside post. Donald the Birder was first with the identification: the multisyllabic Elytrimitatrix undata, yet another spectacular longhorn with apparently no common name. By this point, I had received probably three or four other requests for information about longhorned beetles from various people, which is WAY more than a normal year.

One or two nights after the Facebook beetle post, I got in my car which had been sitting in my driveway with the windows down. Lo and behold, no sooner had I dropped behind the wheel when a suspiciously long antenna poked out from behind the sun visor, and out came a big longhorn! It was dark, and viewing was not great, but I am reasonably sure it was also the clumsy-to-say Elytrimitatrix undata. It scampered to the window and whirred off into the darkness before I could capture it for closer study and possible photos.

Then, just yesterday, Bernie Master noticed an interesting bug on his purple coneflower and managed an image before the thing got away. Voila! Yet another longhorn, this time the supposedly common and widespread banded longhorn, Typocerus velutinus.

Maybe all of these longhorned beetles coming to my attention is just coincidence, but it's way more longhorn action than I normally detect in a season. Most sources seem rather general when describing host species for the three species above; "hardwoods" is a typical but very generic descriptor. As wood-boring beetles often attack the softening tissues of dead or dying trees, I am wondering if the glut of ash trees that have succumbed to the emerald ash borer is producing a bumper crop of longhorned beetles.

If you've seen any longhorned beetles, or have insights into whether this truly is a boom year for them, let me know.

Perhaps it will also be a great year for this longhorned showstopper, the utterly amazing Amorpha borer, Megacyllene decora, which is widely considered to be the world's most spectacular insect. I think this one truly is rare, at least in these parts. The date of our 3rd annual Great Amorpher Borer Expedition will soon arrive, and I greatly look forward to that. For an account of last year's expedition, CLICK HERE. Hopefully expedition members will find many of these showy tangerine beasts.

The joys of ragweed

There are about 1,850 species of native plants in the floristically diverse state of Ohio, and two of those natives are ragweeds (there is arguably a third, but it is too scarce to warrant inclusion). This pair, the common and giant ragweeds, probably rank near the top of the despicable plant list. The ragweeds have tiny, roughened windborne pollen, and it is this pollen blowing on the wind that is a major source of hay fever, the bane of many who venture outdoors.

But as with all native plants insofar as I have become aware, ragweeds have their value, if not to us. As these jolly green giants have been around for a long time, a whole platoon of insects has co-evolved to exploit the plants. Thus, ragweed stands spawn a fascinating ladder of biodiversity. I'll probably win no friends by going to bat for these botanical underdogs, but it is worthwhile to note the value of even the most despised organisms.

First, to dispel a myth. This is not ragweed, nor is it the source of hay fever. In a classic case of guilt by association, Canada goldenrod, Solidago canadensis, or other goldenrods are often accused of being the source of airborne irritants that trigger people's suffering. Not so, the showy, conspicuous wreaths of goldenrod flowers merely bloom along with those of inconspicuous ragweed flowers and often share the same general habitats. Thus, fingers are wrongly pointed at the handsome lemon-colored blooms.

This is giant ragweed, Ambrosia trifida, in its full glory. The spikes of inconspicuous green flowers jut above the massive plants. Our other native is common ragweed, A. artemisiifolia, which is much smaller in stature. Both species are abundant and widespread, occurring in all 88 Ohio counties and far beyond.

Giant ragweed often forms massive stands, especially in moist soil of low-lying fields, river floodplains, wetland margins, etc. Individual plants can reach Jack-in-the-beanstalk proportions, towering to 15 feet in height. Such ragweed groves are typically shunned by all who encounter them.

But life forms much more interesting than the ragweeds themselves have an interwined dependence with the coarse giant "weeds". This is a fascinating little parasitic plant known by the rather distasteful name of river broomrape, Orobanche riparia. It grows on the roots of ragweed, and was thought to be long gone from Ohio until Daniel Boone rediscovered it in a ragweed forest last year. That interesting story may be read HERE.

I am increasingly learning that, if you wish to find cool bugs, boldly venture into or at least around the edge of ragweed thickets. This is an example of what I believe must inarguably be termed a "cool bug". It is one of the species in the genus Rhynchomitra (I don't know which). It is certainly one of the more interesting of the bajillion species of hemipterans known as planthoppers. They make their living by sucking the sap from plants, and at least some are not so high and mighty that they shun ragweeds.

We were quite pleased to come across this magnificent longhorned beetle recently. Quick on the draw in this case, I managed one pretty good photo before the beetle vanished into the thicket. It is Dectes texanus (no common name). While the beetle looks large and impressive in this photo, it is actually less than a half-inch in length, discounting those marvelous antennae. Like some other amazing borers, this one spends much of its life cycle burrowing through the stems of plants, and Dectes texanus is especially fond of ragweeds. Perhaps it could be dubbed the "ragweed borer".

This gorgeous little fly may take the cake in the wacky world of ragweed-dependent bugs. It is the festive fruit fly (my innovation), Euaresta festiva. These tiny flies mostly go unnoticed, which is a shame. They'd be measured in the millimeters, and are so small as to be dismissed as inconsequential gnats or something equally uninteresting from afar. Be sure and click the photo for an expanded view of the critter.

Festive fruit flies are utterly dependent upon giant ragweed. They lay their eggs in the flower clusters - some blooms of the ragweed are in the upper lefthand corner of the photo - and the larvae ride out the winter within the seeds. Come late summer, and the astonishing adults are capering about the ragweed foliage, engaging in eccentric courtship displays. If there is one compelling reason to inspect giant ragweed stands, it is because of the possibility of seeing this marvelous fly.

The genus of ragweeds is Ambrosia, and that translates to "food of the gods". That may be overstating the case a bit, but festive fruit flies sure like the stuff.