Road-Trip Part 3: All About Cedar Gnats

I’ve already mentioned how the rainy weather was a mixed blessing, in that it led to the change of plans that took us to the mysterious Chacoan-style ruin on the Ute Mountain Reservation. But it turned out to be a boon in another regard as well. On the drive back from the hike in the tribal van, I chatted a bit with 2 women (both Cortez locals) seated next to me. I mentioned how sketchy the weather was, and they pointed out that I should be glad because the rain and cold had driven away the Cedar Gnats. They went on to say how this is one of the worst/earliest gnat seasons they can remember. Sure enough, our camping experience that evening was gnat-free.

Tangent: Nice as they were at first, I began to suspect later on during the ride that my seatmates were a few spokes short of a true wheel. I overheard them talking about UFOs and how the international space station crew had been forced to shut off their 24x7 external cameras because it had become too time-consuming to edit out all of the UFO-filled frames before passing along the feed to Earth-bound viewers below.

Nested Tangent: This is as good a time as any to share one of my half-baked theories: Why Otherwise Reasonable People Believe Weird Stuff. I don’t mean like crazy people who think God is telling them to kidnap child-brides. I mean otherwise normal people who believe that aliens regularly visit the Earth to mutilate cattle and impregnate rural people, or who pay to visit “psychics”, or who think evolution is bogus because it’s “just a theory”, or who believe that enviro-liberals cooked up the whole global warming thing so that government could “have more control” over people.

Lots of smarter folks than me have weighed in on this topic- Michael Shermer*, the Editor of Skeptic Magazine, even wrote a book entitled Why People Believe Weird Things. But that never stopped me before from coming up with a half-baked theory of my own, so here’s mine: Because they’re fearful, lazy, or both. People believe weird stuff largely because they lack an understanding of the function, wonder and beauty of the natural world. And because they don’t understand how the world works or how fantastic and beautiful it is, they see it as cold and strange and ugly and scary, and so they turn to stories that seem to provide explanations and excitement and meaning and wonder, when the truth is that if they just spent a little time and effort and attention to understand the real world, they’d see that excitement and beauty and wonder are all around them right now.

*Shermer is also a former bike racer who had a hand in the design of modern-day bicycle helmets.

When people who don’t know much about the desert learn that I like to camp, bike and hike in Southern Utah, they often ask me whether I’m worried about various creepy-crawlies, including scorpions, rattlesnakes and tarantulas. They want to know if I’m afraid of them (I’m not), whether I might step on them (probably not), or if they ever crawl into my sleeping bag (no.) None of these critters worry me. The one critter that does worry me, they never ask about- gnats.

If you’ve ventured into Southern Utah between late May and July 1, you know exactly what I’m talking about- those little “midges” or “no-see-ums”. They’re always right there, hovering around your eyes and ears, driving you crazy. And when they bite, their evil little wounds somehow itch worse than any mosquito bite*.

*And they always seem to get me on the ears, where mosquitoes almost never bite, and those ear-bites just itch like crazy…

Growing up in New England, I had lots of experience with mosquitoes and black flies. While both are annoying, they’re at least big enough to see, and so you stand a chance of killing them. But Cedar Gnats are so tiny as to be quasi-invisible; you wave and swat, but you almost always miss them.

On our last day the weather improved, and we stopped for a hike in Hovenweep National Monument (pic right). And for the first and only time of the long weekend, we finally encountered gnats. Not many, but enough to be aware of. And as we hiked between the fantastic ruins surrounding a large arroyo, I thought about gnats, and realized that I wanted to know 4 things about them:

1- What are they?

2- Why are they biting me?

3- Why are they only a problem in late Spring/early summer?

4- Why are they only here?

This post is what I found out.

What Are They?

Biting Midges occur world-wide. There are thousands of species in the family Ceratopogonidae (blood-sucking flies), some 500-1000 of which (depending on who’s counting) belong to the genus Culicoides. Most midges/gnats are found in wet or semi-aquatic climates, but a smaller number have adapted to more arid environments.

What we call Cedar Gnats in Southern Utah are specifically 9 different (maybe more) species of Culicoides. They hatch in (non-flying) larval form from eggs laid in Spring or early Summer in fissures in the bark of Utah Juniper trees, and crawl around the fissures eating plant debris and algae. The larvae overwinter in the bark fissures until the following Spring when they pupate (like what a caterpillar does to become a moth or butterfly) into flying adult gnats. (Graphic not mine)

The males typically emerge first, and wait around for the females to appear. Mating often occurs at the site of a blood host, shortly after the female has fed.

Tangent: Here’s something cool- a number of Culicoides species are parthenogenetic, meaning they have no males. Alas, I’ve been unable to determine whether any of “our” 9 species are parthenogenetic. The parthenogenetic females still require a blood meal to produce eggs.

Why Are They Biting Me?

Adult Culicoides gnats don’t typically eat blood, but rather subsist on nectar, and in fact they serve as pollinators for some flowers. But the female requires a blood meal to produce eggs (just like mosquitoes) and she seeks a vertebrate* from which to obtain it. So far, this sounds pretty much like the deal with mosquitoes. But here’s where it gets different.

*There are indications that she may hone in on CO2 exhalations to do so.

A female mosquito pokes a teensy hole in your skin with its specialized proboscis, injects a bit of anti-coagulant, and then sucks up your blood through the same organ. The itching you experience is a reaction to the anti-coagulant.

But a Cedar Gnat uses its mandibles to actually saw a hole in your skin, then spits anti-coagulant onto the wound, and then sucks up the pooling blood with its non-piercing proboscis. It’s a sort of more “violent” wound, and this may be why their bites are so much more annoying (and lasting) than those of mosquitoes.

The bites aren’t really harmful to us, with the important exception of people who experience an excessive allergic reaction to the anticoagulant. But they are dangerous to both livestock and wild animals, including horses, cattle, deer and pronghorns, as they serve as a transmission vector for several pathogens, most notably the Bluetongue virus*.

*This one affects only ruminants, not humans.

Horses, in particular, also suffer a much worse allergic reaction than us to the anti-coagulant, a condition known as “Sweet Itch”, which can result in severe skin irritation and hair loss.

Side Note: But in other parts of the world, including Central and South America, biting gnats are transmission vectors for a number of human pathogens, including filarial worms. (Elephantiasis is caused by a type of filarial worm, or more correctly, nematode.)

Why Now?

Between May 15 and June 15 is when they pupate, mate, feast and lay eggs, up to 100 in a batch. Some Culicoides species lay 2 batches of eggs.

Why Are They Only Here?

The thing that always bugged me about these little guys is, why aren’t they in town? By which I mean that you can be out and about in Canyonlands or Arches (pic right = Twin A & me in Arches NP) or on the Slickrock Trail and the gnats will be driving you bonkers, but if you go into a town in the same area/climate, like Moab or Blanding or Cortez, they completely disappear. Why should this be? If they’re so hot for a blood meal, why don’t they zip into town, where there are people (and pets) galore to feed upon?

Because they’re lousy fliers, with a typical range of no more than 300 feet from their hatching tree, and generally Utah Juniper (pic left) doesn’t occur in the middle of a town.

Tangent: There’s still an unanswered question for me though. I can’t swear to it, but I’m almost certain that I’ve been plagued by gnats in open desert/shrubland, when I’ve been well over 300 feet from the nearest Juniper. Either I’m mistaken (always possible), or their range is greater than 300 feet, or they’re able to nest/hatch in the bark of shrubs, such as Sagebrush or Rabbitbrush or Shadscale… I’ll have to pay closer attention on my next encounter…

The easiest way to deal with the gnats is simply to avoid the desert for a month or 2, but late May is otherwise one of the most pleasant times in Southern Utah. Mountain biking in particular is a tricky undertaking. So long as you’re rolling, all is wonderful. But stop for a rest, or a mechanical, and they’re all over in under 30 seconds. Of course they disappear shortly after sundown, but that leaves the issue of what to do with the 16 hour days we currently enjoy…

Tangent: Years ago, I did a solo mtn biking/camping trip in mid-July up on Boulder Mountain. The mosquitoes were unbelievable. On my last ride, I did a 10-mile singletrack out & back- 5 out, 5 back. At mile 9- a mile from the car- I flatted. I had to make a split-second decision: change the tube, or run with my bike for a full mile. I chose the former. I kept my cool, but just barely. With my hands busy, dozens and dozens of mosquitoes feasted on me. Had I flatted a second time (or screwed up the repair) I almost certainly would’ve dropped the bike and run for it.

If you do go desert camping or backpacking in gnat season, the toughest part is sitting around camp. Here are the 2 pieces of protective gear I recommend you bring.

1- Bike socks. If like, me, you typically wear sandals in camp, they’ll go for your ankles/feet. Lightweight bike socks under your sandals will protect them.

2- Head-net. Yes, it looks dorky. After about an hour you won’t care. Arizona Steve and I bring these on every Spring backpack trip. They’re particularly valuable when your hands are busy – cooking for example. We’ve even eaten dinner with them on, raising the lower elastic ring to the “moustache-line” between mouth and nose.

So that’s the deal with those gnats. Me, I’m done with the desert for a few months, so I won’t tangle with them again anytime soon. I think.