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Female Bee Fly at Rest, Bombylius major
The larval stages live as parasites in the
nests of solitary bees (e.g., Andrena, Halictus and Colletes
species), where they eat the food stores and grubs of their
host. I love these little guys, the way they whip about. The
Japanese call them biroudu tsuriabu. Cool.
Order Diptera / Suborder Brachycera / Infraorder Muscomorpha /
Family Bombyliidae -- bee flies, bombiles / Subfamily
Bombyliinae / Tribe Bombyliini |
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Female bee fly's large compound eyes do not meet at the top.
Bee flies are stout-bodied flying insects said to resemble
long-legged
bumble bees, but I've never seen that connection. There are
Syrphid
flies and
robber
flies that do a much better job of impersonating bumble
bees. Many bee flies have elongated mouthparts that form a
conspicuous beak, used for sucking nectar long-distance while
hovering over flowers. Bee flies much prefer to hover in midair
while doing their nectaring, undoubtedly to avoid capture for
those who lurk about flower blooms looking for an easy meal,
such as the
ambush bugs and the
crab spiders. Adult bee flies become active about the third
week in April, here in northern Illinois.
I most often see bee flies hovering around flowers, or if
resting, usually on the ground, on bare soil. They are extremely
wary and difficult to approach. No doubt their large compound
eyes give them good vision, plus they have that air-motion
sensing mechanism that helps the ordinary house fly avoid the
swatter. Adult bee flies drink nectar, but the larvae are
parasites of beetle larvae as well as the brood of solitary
wasps and bees, the hole or burrow-nesting insects. I've heard
tales of female bee flies hovering over a hole in the ground,
flicking her eggs into the hole. I'm skeptical of these claims.
I've often seen female Bombylius sitting in very loose soil,
vibrating her butt like mad, so that the dirt is actually thrown
outwards (see our
Bombylius major pictures). This, I think, is one egg-laying
process.
Many bee flies have boldly patterned wings, but it's their
shape that generally tips me off that a specimen is in the
Bombyliidae family. The shape is reminiscent of the best
swept-wing fighter jets. The relatively short and usually
pointed antennae are another clue, along with, of course, that
dangerous-looking beak. Good thing these flies don't bite or
sting. All in all, a fascinating insect worthy of study. Next
springtime, why not take a trip to the woods? You'll find these
gals busily gathering nectar from the dandelions along your
favorite sunny path. Just watch out for the dog poo.
Bee Fly vibrating her abdomen in the dust. Gif Beaton claims they are gathering
sand to coat their eggs.
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