Insect Picture of the Day

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The more field trips I take to photograph bugs, the better I get at spotting them. As my wife and I strolled along the wetlands trail, I looked over at this tall milkweed plant and found my attention immediately drawn to the tiny midge hanging underneath this leaf. The backlighting and framing seemed nice to me, and as you can surmise, I just happened to have the camera with me.

Winter fired its first warning shot this week, with temperatures dropping to 1°C (33°F) and dropping a brief flurry of snow. Insect activity around my neighborhood has fallen off quite sharply, even as temperatures returned to the high teens (mid-60’s), but I am surprised to find that the midges are still hanging in there. I saw three praying mantises last weekend, and the funnel-web weavers nesting on my front porch seem unfazed, but other than that it’s really quiet out there. Most of the flying populations seem to have been wiped out, and with them, flying predators. Looks like I won’t be seeing any more meadowhawks until next year.

But the midges are still here. Still in droves, even. I wonder if they’re still going for just one more life cycle this Fall, if their larvae are still pupating even in this weather… or if they’re just laying their eggs to overwinter in the ponds and lakes nearby.

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Here’s one of the last midges of the season, artfully posed on a poplar tree along a wetland trail near Utah Lake. You’ll need the larger version to see the midge closely; I found the scenery framing this image in soft-focus to be as compelling a part of the image. Here’s a zoomed-in version of the midge itself. Note that this species is a little bit different than the midges I have posted in the past; I’ll try to get a better picture of one later.

This female midge is heartily braving the late September night temperatures here. Last night got down to 0.5°C (33°F). For better survival in temperate climes with wild temperature fluctuations, many insects have evolved criostatic compounds in their blood and organs, enabling them to shut down without dying when temperatures hover near or even dip a little below freezing. They can’t actually survive being frozen solid, but the same criostatic compounds that allow them to survive chilling also act as antifreeze, allowing them to remain unfrozen a few degrees below zero. Since Autumn temperatures occasionally reach freezing but rarely plummet more than a degree or two below, this allows them to survive nights of severe exposure. The midges seek out places to spend the night where they hopefully won’t get eaten, and then go into an overnight hibernation mode. This effectively extends their yearly activity cycle by as much as three months here in Utah, where daytime temperatures still get up to 26°C (80°C), which is perfect for flying, feeding, frolicking, and of course, making more bugs.

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This a male chironomus midge (females lack antennae plumage). Chironomids do not bite; in fact, as adults they do not even feed. As a result they have a lifespan of 3-5 days once reaching adulthood. Midges are among the most populous insects to inhabit manmade and stagnant watercourses, especially sewage drainage and irrigation drainage where there is plenty of decomposing matter. In nutrient-rich water, midge populations can easily exceed 4,000 larvae per square foot in the mud bottom. Chironomid larvae are called bloodworms because they are a deep red color, caused by hemoglobin in their blood, which is very rare in insects. The iron in their blood helps retain oxygen down in the nitrogen-rich (but oxygen-poor) muck they thrive in.

Midges are a very common in neighborhoods of newly constructed housing adjacent to slow-moving or stagnant fresh water. (Like my neighborhood.) They are considered a nuisance pest by some, but I actually like them. Just remember to keep your mouth closed when they’re swarming. Of course, the reason I like them is that midges provide an excellent food source for spiders which thrive quite joyously on daily midge feasts.

This little guy is almost 12mm long (not counting antennae or legs), which is actually rather huge for a midge, and makes me think he’s probably chironomus plumosus, the only species to commonly exceed 10mm, but dicrotendipes modestus (also in family chironomidae) is more likely to inhabit the kinds of ponds and vegetation we have here. I’ll have to take my camera to the pond and hunt for larvae. If I can find them at all, they’ll be dicrotendipes modestus, because plumosus larvae prefer water several meters deep (and I’m not swimming for photos).