A fly in bee’s clothing

From L to R:  bumble bee and a bee-mimic fly Photo credit: Karen Perez

From L to R: bumble bee and a bee-mimic fly Photo credit: Karen Perez

Whether you’re looking at caution signs or a buzzing insect, black and yellow stripes mean danger. At least that’s what the insects would like you to think. Sure, bee and wasp stripes threaten a sting, but there are plenty of harmless insects that suit up in yellow and black too.

Numerous flies, beetles and even moths look like bees, at least at first glance. This collection of bee doppelgangers is collectively referred to as “bee mimics”.

Bee mimics have many purposes for looking like their distant relatives, some harmless, but some nefarious too. Whether they’re helpful or harmful to the creatures they’re copying, these mimics could be buzzing around your yard this summer.

Copying the look of a distant relative is common in nature. Mimicking animals often steal the look of a poisonous, stinging or otherwise dangerous animal. By replicating the look of something with strong defenses, predators will avoid the copycat just like it was the real thing.

Mimicking can be an offensive move too. In this case a predator apes the look of a harmless animal. This allows the actually dangerous mimic to sneak up on prey without their knowing.

A wide range of flies mimics bees – for both offensive and defensive purposes.

For example, bee mimicking helps the robber fly catch one of their favorite snacks – actual bees. Because robber flies closely resemble bumblebees they can get up close and personal with their prey without causing an alarm. Based on this sneaky bait-and-switch act, it’s no surprise that this group also goes by the name “assassin flies”.

Not all mimics are hungry for a bee snack though. Some species, like the drone fly are just interested in drinking nectar. Drone flies are the spitting image of a honeybee and just like the insect they’re copying, the flies are important pollinators. Similar to honeybees, when the flies go in for a sweet meal they get dusted with pollen. The freshly dusted fly will then transfer the pollen to the next flowers they visit.

Sometimes the actions of bee mimics aren’t so straightforward. The aptly named Large Bee-Fly is a chubby and fuzzy insect. Adults have a long tongue for feeding on nectar and pollinate flowers like drone flies. The larvae have a more sinister food source. Adult females use their disguise to buzz in near a bee nest and flick eggs near the opening. Once the eggs hatch, the larvae wiggle into the nest and munch on bee grubs.

Bees clearly have difficulty in identifying mimics, but with a few tips, you can pick out the fakers better than a bumblebee. Both bees and mimicking flies can be fuzzy and be striped black and yellow. A major difference is in the antennae. Bees have long antennae with a single bend that extend roughly the width of their head. Flies on the other hand have very short, stubby antennae that stick straight forward.

To discover more bee mimic clues have a look at the helpful website put together by The University of Illinois, complete with photo examples: https://beespotter.org/topics/mimics/. After perusing their list of bee vs. mimic differences you’ll be ready to impress your friends with your identification skills at the next summer barbecue.

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