Aposematism - Can't Touch This
Imagine this: you're in a flower garden, surrounded by fragrant blooms
of every color and shape. As you reach to pick a particularly lovely
flower, out of the corner of your eye you notice a flash of
yellow-and-black stripes. What do you do?
I'm going to guess that your immediate answer is something along the lines of "Pull my hand away before I get stung!" And it's a more than reasonable response. But how did you know?
Most of us have probably been conditioned to this response from unpleasant first-hand experience with yellow-and-black striped stinging insects. Those of you lucky enough to have avoided being stung might still know that these colors are worth staying away from due to "group knowledge." The yellow-and-black stripes of a bee are forever associated with its painful sting.
This is a phenomenon called "aposematism," which is a fancy way of saying that an animal displays bright colors to warn others about a nasty sting, toxin, or other unpleasantness it has in reserve. But we have to remember that aposematism, just like anything else in the Earth's evolutionary history, did not arise with intention. That is to say, ancient bees did not have a meeting to say, "Hey, let's all wear bright colors to warn other animals about our stings so we don't get eaten!"
Long ago, bees came in a variety of colors that had nothing to do with their ability to sting. However, yellow-and-black striping is highly visible to other animals, especially predators. After dealing with one yellow-and-black bee that stung, I'm sure most of us would learn to avoid them in the future! This helped bees wearing that color combination survive better and go on to produce more bees with similar coloration.
But more than one type of insect stings, yet they all seem to share the same basic coloration and pattern. Many bees, wasps, and hornets demonstrate the same aposematic coloration. This is what we call "Müllerian mimicry." All of the yellow-and-black species benefit from using the same pattern of warning colors: it's easier for predators to learn to avoid, so more of the insects wearing that color combination are successful.
Some of the yellow-and-black things buzzing around the flowers in that hypothetical garden aren't bees, though. Syrphids, also known as hover flies, have adopted the coloring of bees and wasps as a way to protect themselves from predators, even though they can't sting! This sneaky strategy is known as "Batesian mimicry," and it means an animal can use warning coloration to deter predators without the costs associated with producing a sting, toxin, etc. It's the "best of both worlds" approach.
Of course, the yellow-and-black stripe combination is far from the only aposematism we can find in the insect world. The beautiful orange-and-black coloring on a Monarch butterfly indicates not a sting, but rather a poison that the butterflies acquire from their host plant, milkweed. (This coloring example also holds true for the similar viceroy butterfly, although there's some debate about whether the mimicry going on here is Müllerian or Batesian.) Other insects that may demonstrate aposematism or mimicry include aphids, grasshoppers, and caterpillars of moths and butterflies.
The next time you find yourself reaching for a flower in a garden and you see a flash of yellow-and-black, take a moment before you recoil to look more closely at the insect flying by. Maybe it will be a hover fly, and you can examine its cunning mimicry. But if it is a bee or a wasp, remember to admire its aposematism from a safe distance.
 |
| Photo courtesy of Woody Meristem |
I'm going to guess that your immediate answer is something along the lines of "Pull my hand away before I get stung!" And it's a more than reasonable response. But how did you know?
Most of us have probably been conditioned to this response from unpleasant first-hand experience with yellow-and-black striped stinging insects. Those of you lucky enough to have avoided being stung might still know that these colors are worth staying away from due to "group knowledge." The yellow-and-black stripes of a bee are forever associated with its painful sting.
This is a phenomenon called "aposematism," which is a fancy way of saying that an animal displays bright colors to warn others about a nasty sting, toxin, or other unpleasantness it has in reserve. But we have to remember that aposematism, just like anything else in the Earth's evolutionary history, did not arise with intention. That is to say, ancient bees did not have a meeting to say, "Hey, let's all wear bright colors to warn other animals about our stings so we don't get eaten!"
Long ago, bees came in a variety of colors that had nothing to do with their ability to sting. However, yellow-and-black striping is highly visible to other animals, especially predators. After dealing with one yellow-and-black bee that stung, I'm sure most of us would learn to avoid them in the future! This helped bees wearing that color combination survive better and go on to produce more bees with similar coloration.
But more than one type of insect stings, yet they all seem to share the same basic coloration and pattern. Many bees, wasps, and hornets demonstrate the same aposematic coloration. This is what we call "Müllerian mimicry." All of the yellow-and-black species benefit from using the same pattern of warning colors: it's easier for predators to learn to avoid, so more of the insects wearing that color combination are successful.
Some of the yellow-and-black things buzzing around the flowers in that hypothetical garden aren't bees, though. Syrphids, also known as hover flies, have adopted the coloring of bees and wasps as a way to protect themselves from predators, even though they can't sting! This sneaky strategy is known as "Batesian mimicry," and it means an animal can use warning coloration to deter predators without the costs associated with producing a sting, toxin, etc. It's the "best of both worlds" approach.
 |
| Photo courtesy of Woody Meristem |
Of course, the yellow-and-black stripe combination is far from the only aposematism we can find in the insect world. The beautiful orange-and-black coloring on a Monarch butterfly indicates not a sting, but rather a poison that the butterflies acquire from their host plant, milkweed. (This coloring example also holds true for the similar viceroy butterfly, although there's some debate about whether the mimicry going on here is Müllerian or Batesian.) Other insects that may demonstrate aposematism or mimicry include aphids, grasshoppers, and caterpillars of moths and butterflies.
The next time you find yourself reaching for a flower in a garden and you see a flash of yellow-and-black, take a moment before you recoil to look more closely at the insect flying by. Maybe it will be a hover fly, and you can examine its cunning mimicry. But if it is a bee or a wasp, remember to admire its aposematism from a safe distance.
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