Geron bee flies are more slender than most of their relatives and have a “humpbacked” appearance because their thorax bulges up in the back (dorsal surface).
As stated at BugGuide, the adults use their long, prominent proboscis to drink nectar from flowers. They seem to prefer sunflowers.
Because of their fuzzy bodies, they pick up pollen while feeding on nectar. When they carry the pollen to another flower, they help pollinate it.
So why were there so many of these flies on the palo verde tree this morning?
Looking closely, I noticed some caterpillars. Bee flies are parasites of other insects in general. Geron bee flies are parasites of caterpillars. These adults were probably looking for a caterpillar to lay their eggs on.
I’m going to spend some time watching the caterpillars to see if I can find out more. Look for an upcoming post about them.
Until then, do you have Geron bee flies in your yard? What flowers are they visiting?
If someone asked you what kind of insect this is, what would you say?
Because of that long beak (proboscis), it looks a bit like a mosquito, doesn’t it?
Actually it is a bee fly in the genus Geron.
Many bee flies, as their name suggests, resemble small, furry bees. The flies in this group, however, are more slender and they have a “humped” appearance.
The Geron bee flies share a similar lifestyle with the other bee flies. The adults use the long proboscis to drink nectar from flowers, and are considered to be beneficial pollinators. The larvae are parasites of other insects, generally moths.
Seems that in the insect world, as with elsewhere, appearances can be deceiving.
After being on the look out last week for flies, it wasn’t surprising that I spotted this one resting in the sun.
I knew right away what is was.
A fly with a fuzzy body and colored wings, it had to be a similar species to the illustration I have framed on my wall.
This illustration is by Edmund J. Detmold, who was born in 1883. On the print you can see his initials, EJD, in the corner.
Detmold did this illustration for Fabre’s Book of Insects in 1921. Jean Henri Fabre was a French entomologist known for his keen observations of insects and his poetic text. The last chapter of his book is devoted to the habits of “The Anthrax Fly.”
On the back of my framed version it says,
“The Anthrax Fly: Her delicate suit of downy velvet, from which you could take the bloom by merely breathing on it, could not withstand the contact with rough tunnels.”
The fly in the picture is a bee fly of the genus Anthrax. These flies usually lay their eggs in bee or wasp nests, which are the tunnels from the quote. Their larvae are for the most part parasites of bees and wasps.
You can see more photographs of bee flies in the genus Anthrax at BugGuide.
Sometimes discovering an insect can feel like discovering a bit of history.
A translated version of Fabre’s Book of Insects is still available from Dover Publications, although Detmold’s illustrations are not included.