#conopid fly

[have-you-seen-this-animal]

Conopid fly mayhaps?

Have you seen a conopid fly (Family: Conopidae)?

I have now

Yes, in photos/videos

Yes, irl

I'm not sure

Voting ended onJan 8, 2025

Photos thanks to the wikipedia commons and Marlin.

[jonnysinsectcatalogue]

Common Eastern Physocephala - Physocephala tibialis

With Potter Wasps finally introduced to the blog, we can also explore these curious Flies of the garden that were stumbled onto this year. These strange looking insects were drawn to the yard’s oregano and also seem to like perching on rose leaves as well. Akin to Hoverflies, these insects mimic other stinging Hymenopterans in order to avoid becoming someone’s dinner. The insects mimicked in this case are Potter Wasps which are a handy family to mimic since Wasps are likely to retaliate if disturbed. If the mimicry holds, the false warning allows this specie to enjoy flowers at their leisure. However, this specie of Fly is not a Hoverfly, and belongs to another Fly family altogether! To tell the two apart, this Fly has a long proboscis jutting from its face which it uses to slurp up nectar from the plants it visits. Hoverflies lack this proboscis; they lap up nectar with a spongy-mouthpart (this video here provides a great example of this feeding). This Fly belongs to a somewhat elusive family called Conopidae (Thick-Headed Flies). It’s an odd name considering the individuals photographed in this post, but that’s the family they were sorted into. 

While they share some behavior with insects like Hoverflies and Bee Flies, these insects have their own habits and traits. Firstly, a fun example of their habits is the piling behavior shown in Pictures 4, 6 and 8. It’s not necessarily that there is a mating pair going on, they might just be piling on each other for kicks. Unlike more common Flies, males and females of this specie aren’t distinguished by their eye placement. Instead, watch for the abdomen position and the structure of the abdomens to confirm a mating pair. Since the individuals on display here have rounded abdomens, it’s likely that we are seeing two males in a pile (which can get as tall as 3 or even 4 individuals). Why do they pile? Who knows, but it’s an odd behavior! Interestingly, there doesn’t seem to be much struggling or infighting during the process. I can only speculate, but it may be a vigilance behavior or somehow involve mate selection. While we know now what males look like, look for the abdomen to have a claw-shaped tip (curving downward) to identify a female. Such a clawed tip is for more than just for show, and we’ll dive into that behavior on the next posting of these Flies. It’s very important that gardeners keep an eye out on these Wasp-mimics in order to protect their Bees...

Pictures were taken on July 21, 28 and August 20, 2020 with a Google Pixel 4.