The Fly That Wants to Be a Bee

A bee or not a bee – that is the question when you get buzzed by a newly-discovered species of fly that looks very much like a bee. To add a little more sting to this new fly, it’s the first insect species to be classified using only high-resolution photographs and not dead specimens.

Discovered by Drs. Stephen A. Marshall from the University of Guelph in Canada, and Neal Evenhuis from the Bishop Museum in Hawaii, the rare bee fly known as Marleyimyia xylocopae is native to South Africa and looks strikingly like a carpenter bee (Xylocopa flavicollis).

According to their study published this week in Zookeys, Marshall took the high-resolution photographs of the bee fly and Evenhuis used them to determine it was a new species – one of only three bee flies of the genus Marleyimyia and the only one that isn’t nocturnal.

Why did this fly evolve into a doppelganger of a carpenter bee? Marshall and Evenhuis haven’t figured that out yet. It could be a form of Batesian mimicry (often seen in butterflies and named for English naturalist Henry Walter Bates) where a species takes on the looks of a poisonous or menacing species to scare away predators. It could also be a parasitic trick to fool carpenter bees for some purpose – like eating their food or their eggs. That determination requires further analysis.

And probably some dead flies. The decision to allow Marleyimyia xylocopae to be declared a new species based solely on photographs was controversial among entomologists. A two-dimensional photo – even in high definition – cannot show odd colorations or shapes. Since a picture can’t be dissected or placed under a microscope, it can't be analyzed to identify or clarify traits that might answer questions like why this fly looks like a bee. A video, a dead specimen or a living bee are obviously needed.

Or are they? What if it’s the last of its species? Do we really need to name everything? Do we really need to kill everything?