When flies want to be something else

At the behest of nathalie with an h, I headed across the blogosphere to help Nezza with an insect question.

She had photographed what at first looked pretty much like a bee, nice and plump and buzzing about and doing all things with a very bee-like demeanor and display.  But looks can be deceiving, especially when it comes to flies.

What Nezza photographed happens to be either a bee fly or a syrphid fly.  Masters of disguise even as lower order insects go, this diverse group of creatures has filled every possible niche of mimicry imaginable—and especially when it comes to looking like higher order insects like ants, wasps and bees.

A bee killer (a.k.a. robber fly or asilid fly; Mallophora fautrix) perched on a blade of grass (20080726_10085)

Called a bee killer (a.k.a. robber fly or asilid fly; Mallophora fautrix), this happens to be a predator that will attack any flying insect.  It isn’t as large as the giant robber fly (Promachus hinei) I posted a few weeks ago, but the bee killer is just as bold in that it will chase anything it thinks it can overpower.

A hover fly (a.k.a. syrphid fly; unidentified) perched on a blade of grass (20080726_10086)

Hover flies (a.k.a. syrphid flies; unidentified) cover a lot of territory when it comes to looking like anything but a fly.  Although completely harmless, they perfectly impersonate some of the most troublesome stingers: bumble bees, yellow jackets and hornets to name a few.

As I explained to Nezza, flies can’t hide their identities despite their best efforts to look like another species.  As all flies go, they still only have one pair of wings (bees, wasps, dragonflies and all other higher-order insects have two pairs).  Flies of this sort also have short antennae (not true of all flies, but true of the suborder Brachycera that happens to include most flies; members of the suborder Nematocera, which includes crane flies, gnats, mosquitoes and midges, have longer antennae).

This also brings to mind a recent experience with xocobra as he pointed out the abundance of flying ants around his house.  While standing in the garage enjoying a cold adult beverage and camaraderie, one such menace flitted by and landed atop the hood of one of the cars.  He immediately pointed it out and noted it came from the same species of ant to which he had referred.

But it was no ant at all; it was a fly.  More specifically, it was a type of picture-winged fly in the genus Delphinia (probably Delphinia picta, although I only saw it briefly).  Looking very much like a winged ant in color and shape, I couldn’t blame him for letting his eyes state what seemed terribly obvious.

The next time you see a bee or wasp or dragonfly or ant, ponder for a moment if you are seeing what you think you are seeing.  It’s quite possible—and in many ways probable—that you are looking at a member of the order Diptera, a true fly, and you happen to be graced with viewing the splendid diversity of mimicry that exists in these primitive creatures.

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