Hover like an indecisive bee, buzz like a bee if not louder, look just like a bumblebee; must be a bumble bee right? When is a Bumble Bee not a Bumble Bee?
Bare-cheeked Bumble Fly
Criorhina nigriventris
According to The Field Guide to the Flower Flies of Northeastern North America, Skevington & Locke, flies carry out about one-third of our pollination services.
So much to discover in our backyards! We look for life in the stars while our own yards are immensely underexplored for the countless species that live there.
However, many other species of flower flies seem to have a general appearance or a gestalt of a bee or a wasp if you will. This has raised some questions as to whether it is classic mimicry at all or if so, how does it function. In other words, how is that general resemblance maintained in an evolutionary sense? And then, given a large number of species of flower flies, it is not surprising to learn that many species don't resemble bees or wasps at all, at least to the human observer. These are almost inevitably overlooked in general surveys.
I noticed the phenomenon of mimicry perhaps 50 yrs ago, especially in the Victory Bog WMA when I was first becoming aware of syrphids and how many were incredible mimics, to the point of completely fooling me.
For example, when I first handled with great trepidation what I thought was a stinging hymenopteran, I soon learned that not only is mimicry based on shape, pilosity, and color patterns but with many some mimics there is a distinct behavioral difference. I learned that some of the mimics buzz like a bee much more loudly than the real thing. In fact and somewhat paradoxically, this was often the tip-off that I could safely touch the individual without fear of being stung.
One might even think this could be counter selective because a predator of the harmless fly, might learn that indeed by its extraordinary louder buzzing, in fact, it is not a bee or wasp. One knows that one can cry wolf just so many times if no wolf is present before the shout is ignored. At what evolutionary stage does the loudly protesting mimic have to change its behavior? Certainly, not all hover fly mimics are not acoustic mimics of the buzzing of bees say. Why is that the situation?
The phenomenon of mimicry in flower flies is just one example of how little we know about them as a group. And the evolutionary significance of the variety of mimicry patterns in the animal worlds has been studies and dated for decades by scientists. Syrphidae represent an ideal group to clarify many of these perennial questions about mimicry as a general biological pattern in many animal-and even plant groups. And this area of research is now a very active one with the syrphidae. Why does man do this? Well, supposedly he wishes to understand as completely as possible the world that he shares with other organisms. Paradoxically, we are still living on a very mysterious planet, despite what many may think.
They are an extraordinary diverse major family of insects with many major differences in their biology. In general, they impact ecosystem functioning and services in many ways, and we know little about most of these. In fact, new species of flower flies are still being discovered here in N. America every year, even in this general area. We hardly know anything about the ecology of most. In fact, we don't even know how many species there are in Vermont except at a very general level of documentation.
Citizen scientists could greatly help in documenting the number of genera and even many species in the State, by simply taking very good photographs of actual or suspected flower flies in their gardens or other habitats around their property.
If possible photographs should include frontal, lateral, and top or dorsal aspects. of individual flies. Most naturalists take the latter which is generally good enough for identifying an individual to genus by even non-specialists who have the Skevington et al Field Guide. In fact, I would encourage simply photographing any insect following the criteria mentioned here, not just those thought to be flower flies. Better to err, than to miss documenting a genus of flower fly previously unknown in the State Keep in mind that some species of flower flies do not regularly visit flowers or never do. Look for them on stumps in the woods and places like that, as well.
Don Miller
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