The Great Moth/Bee

5 March 2019

Hemaris diffinis, the snowberry clearwing, is a moth of the order Lepidopteria, family Sphingidae. Notable for its nicknames, such as “hummingbird moth” or “flying lobster”, it bears close physical resemblance to many other animals, albeit genetically unrelated. However, the clearwing bears the greatest resemblance, perhaps, to bombus impatiens, the common eastern bumblebee, among which it can blend in almost perfectly.

The golden sun filtered through the greenery outside and fell on her weathered hands. She leaned forward, elbows resting on the pine tabletop.

“So tell me a bit more about what you’re researching—moths, is it?”

“Yeah…well no, I’m actually writing a paper about morphological mimicry among various animals, but I’m interested in one specific species of moth at the moment, the snowberry clearwing? I hear they’re native around here and I was wondering if any had ever gotten mixed in with your bees.” I passed the beekeeper a photograph of an insect. It had a fuzzy golden thorax, thin black legs, and a black abdomen adorned with two yellow stripes.

The snowberry clearwing doesn’t just look like a bumblebee—its behaviour is also remarkably similar. Like bees, it consumes nectar from flowers, and unlike other moths, it flies diurnally. Their main distinguishing factor is their flight patterns; bees move their wings far more swiftly than moths do, making the moth look slightly clumsier in comparison.

“I actually think one of them might’ve,” she replied, mildly fascinated. “I had a funny-looking bee appear a while back, dunno where he came from really. Stuck around and blended right in with all of mine for a little bit, thought I was going a bit nuts; I even went and dug out my old specs. Then I realised the bugger was flying a little funny, and its wings were pointy. I didn’t know what it was, so I had to kill it. It’s a pity…”

“What do you mean, ‘flying a little funny’?”

The snowberry clearwing reproduces like other moths—after the male locates a potential mate, he chases the female until she falls for him, literally mid-flight. Therefrom, the male flaps his wings and moves his antennae in a sort of ‘dance’, releasing pheromones to allure his mate. The clearwing is a rather more ostentatious performer, with a more concerted, elaborate routine than other species.

“You’re telling me it was this moth trying to seduce my bees?”

“Probably just one bee, but yeah—sometimes clearwing moths will see bees and confuse them for other moths, and honestly who can blame them?”

She laughed drily. “Well, does that help with your research at all?”

I paused to grab some pen and paper. “Actually, I wanted to ask if you observed any changes in your bees’ behaviour while the moth was around. Was it business as usual, or did anything feel a bit off?”

Animal mimics are generally harmless. Sometimes, the mimicry is an evolutionary outcome where a vulnerable species adopts the phenotypes of a more aggressive, intimidating one. This is the case for clearwings, having evolved to look and behave like the venomous bumblebee. Meanwhile, the mimic and the species being mimicked usually coexist in peace, only ever interacting accidentally.

What makes the case of the clearwing interesting is that it mimics a species renowned for its swarm intelligence, a species that frequently exhibits complex, coordinated behaviour as if an entire hive was one single organism.

I met with a beekeeper who’d witnessed such a response to a snowberry clearwing. She noted an increase in the aggression of her bees, behaving markedly more erratically while the harmless clearwing was present. The moth had appeared in the ecosystem during its mating season, and made repeated failed attempts to mate. It was when these attempts became too overt that the beekeeper eliminated what she perceived as a potential threat to her bees.

However, I posit that even without intervention, the bees would’ve eventually purged the imposter by themselves. Animal mimicry is oft understood as an evolutionary defence, yet we should concede that it can be imperfect. The mimic evades predation, but without the guarantee of safety from the species being mimicked. And so the world beats on…

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