Wednesday, October 24, 2012

An Explosion of Crane Flies

Charles Alexander was a Crane Fly connoisseur without parallel. Over the course of his career as an entomologist, Alexander did his darndest to delineate the members of the Order Diptera - flies - with an especially tight focus on Crane Flies. By the time he died in 1981, at the grand old age of 92, Alexander had described over 11,000 species of flies, including some 3,000 Crane Flies. That is a truly remarkable accomplishment, and the good Doctor must have been a whirlwind of productivity.

Here's a Crane Fly. I took this photo this evening, by the front door of my house. I'm sure you've seen these insects; they are quite conspicuous, looking somewhat like mosquitoes on steroids. A female of one of the larger species, such as this specimen, can have a leg span of three inches. Many a Crane Fly illiterati has panicked and then pancaked these interesting bugs, thinking them to be super mosquitoes when in reality Crane Flies are utterly harmless and don't bite or sting.

I wish I could tell you exactly which species this one is, but I don't know. Maybe an expert will see this and be able to tell us. Whether one or more species is involved, this has been an absolute boom year for Crane Flies. I've seen scores of them - far more than I recall in other years - and others have made mention of the same thing. Most adult Crane Flies apparently don't feed; they live only to mate and reproduce. Their larvae, which resemble grubs, DO eat and turf grass roots are a target of some species.

Up close and personal. This specimen still has all of its six legs. It's not uncommon to see Crane Flies with missing legs, as these spindly appendages are easily shed. Note the haltere that is visible just below and behind the far wing. Click the photo to expand and you'll see it much better. It's the short filament with a knobbed tip. A haltere is a highly modified wing, and a trademark of flies. Over time, their second set of wings has evolved into these little gyroscope-like appendages that serve to stabilize the animal as it flies.

If anyone knows why there seems to be such an explosion of Crane Flies this fall, please do tell.



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6 comments:

Lisa at Greenbow said...

It is funny you should ask this question. I was hoping to find the answer here. We noticed here in SW Indiana that the Crane Flies were all over the place this weekend. We have had quite the warm spell here. Nearing record highs for this area. Love these up close and personal pictures you are getting with that new camera. Can't wait to see more.

Dave McShaffrey said...

Jim, It does seem to be a good year for them. Not sure why. The thing that really intrigues me, however, is how the bigger species only seem to come out early in the spring - and late in the fall. Just outside of dragonfly season. Coincidence? I think not.

Lona said...

On a trip to Gallia county the first of the month I noticed swarms of Crane flies.

Jim McCormac said...

Janet Creamer sends along the following possible explanation for the crane fly boom, and it sounds good to me - thanks Janet!

Hi Jim,

I found a plausible answer for the crane fly boom. Texas had similar
conditions last winter, with a drought followed by lots of rain.
Apparently, crane fly larvae thrive on that, because they love rotting
vegetation. Drought kills the plants, the rain helps them rot. Crane fly
larvae find lots of nums. J

Janet Creamer said...

Hi Jim,

Thanks, but I cannot take credit for the info. Mike Quinn is the researcher that proposed that explanation. The link to the article is below

http://kut.org/2012/03/rain-causes-crane-fly-population-boom/

Jim McCormac said...

Well, I CAN give you credit for sharing that research -thanks Janet!