This critter followed me in from the back yard and gave me a merry chase to capture it. After I photographed it through a magnifying box it returned to nature. Its markings are distinctive enough to identify it as a tiger bee fly (TBF), Xenox tigrinus. It is common enough to warrant its own page in the MDC Discover Nature field guide.
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| Tiger bee fly- ventral view |
TBF is a true fly, equipped with a single pair of wings and it can hover like a bee. It doesn't bite or have a stinger but looks intimidating enough that I didn't consider grabbing in with my hand. It has a straw-like mouth tube or proboscis which some bee fly species use to collect nectar from flowers. They likely are an occasional pollinator although they don't get down and wallow in the pollen like a bee does so they aren't very efficient.
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| Tiger Bee Fly - Chris Barnhart |
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| TBF egg and larva - Mike Ferrro CC |
Now the bad pollination news. Bee flies are named because of their appearance in flight but they have another bee association. Bee flies lay their eggs on bee larvae and their emerging larvae will then consume the bee's offspring. TBF specializes in carpenter bees, Xylocopa. For this reason the adults are frequently seen around wooden privacy fences, wooden roof overhangs, and similar wooden surfaces.
Chris Barnhart says, "It’s a Bald-faced hornet mimic. I watched both the model (hunting insects at the sheet) and the mimic (buzzing around the tailgate of my car). The resemblance is eerily good, posture and flight pattern as well as color and markings.
So, are bee flies good or bad? The answer as always is "it depends."
More on bee flies is at this USFS site and Bug of the Month.
Ben Caruthers caught this Hunched-back Bee Fly in action, nectaring on Rudbeckia, their favorite species. Just too good a photograph to pass up.