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Top 10 Insect Mimics
The World's Most Amazing Insect Mimics
When it comes to the insect world, things are almost never what they seem. Between the perfect camouflage of leaf insects and the fake wasp markings of syrphid flies, you're never really sure of what you're looking at. When an animal tries to look like something it isn't, it's known as a "mimic." This guide will show you some of the most amazing insect mimics the world has ever seen.
Here you'll find a moth that looks and acts exactly like a hummingbird, and another that is a dead-ringer for a bumblebee. You'll see a caterpillar that can puff up its head and show big "snake's eyes" to scare away predators, and another that looks so much like a fresh bird poop that no bird in its right mind would take a peck.
Come have a look at these and many more brilliant impostors...
The Hornet Fly
In the insect world, it pays to look dangerous. There are a lot of genuinely scary bugs who can sting or bite, but there are almost as many that simply look like they can. Dangerous insects like wasps advertise their power with bright "aposomatic"" colors -- black and yellow are especially common warning colors. When a bird or a frog sees those colors, they think twice before going in for the kill. The wasp or bee never even has to use its stinger because the predator species has learned over eons of evolution to associate the pattern with danger.
But what do you do if you're a perfectly edible fly who only wants to stay alive? You can't sting or bite or defend yourself in any way. You're not especially big or fast. The solution, for some species, is to use those warning colors to fool predators into thinking you're a dangerous wasp or hornet. Over millions of years, the offspring that come out with brighter contrasting colors tend to survive. As a result there are plenty of harmless insects look an awful lot like dangerous wasps and hornets.
Of the harmless flies that imitate dangerous wasps, the hornet fly, Spilomyia fusca, is one of the best.
It's hard to believe that this insect is just a fly and can't sting you at all. It's a testament to the power of the black-yellow warning sign that even those who know the insect is harmless hesitate to take it in hand. Hornets have one of the most painful stings of all wasps. Why even risk it?
Spilomyia fusca has the look of the hornet down to the last detail -- look at the pale markings on the thorax (the insect's "back") and the way the wings look just like the hornet's. Here's the freaky thing about the wings: The hornet has a pair of wings on each side, but flies only have one wing on each side. To make the copycat even more accurate, the fly's single wings have dark shading that makes them look like they're doubles.
Side view showing the fly's "flat" abdomen
The fly's abdomen, the third segment that has the pale yellow stripes and looks like it also has a stinger (but doesn't), is another bit of deception. The hornet has a round, "fat" abdomen, but the fly's is flat: from the top, it looks just like the hornet's, but viewed from the side you can immediately see that it's totally different.
Let's have a look at the real thing: a Bald-Faced Hornet
Did you get that? This is the fly...
And this is the hornet.
These two are almost indistinguishable!
It's pretty easy to see why a predator, or human, would think twice before picking on either one of these insects. The hornet lives in a big grey nest up high in a tree, where several hundred individuals work together to provide food, shelter and protection for their defenseless larvae. If the nest is disturbed, the hornets swarm out and attack. This is one of the largest wasps in the genus Vespa, and they can deliver a truly painful sting. A whole hive of them can easily put you in the hospital.
The fly, on the other hand lives by itself. It feeds on pollen and hangs out in sunny meadows with butterflies. It looks dangerous, but it's all a front; if any bird or frog decided to take the risk and gobble up the fly, they would find it delicious and filling. The evolutionary "strategy" that has led this animal to look like it does provides just about the only protection it has.
The next insect mimics are also trying to fool predators, but the story is a bit different...
Hummingbird and Bumblebee Moths
This is the moth:
This is the female ruby-throated hummingbird:
The Hummingbird Moth
It's one thing when a fly tries to look like a wasp -- flies are relatively closely related to wasps, and the leap from fly to wasp isn't really that hard to make. But what about when a moth pulls the same trick? The two species in this section, Hemaris thysbe and its congener Hemaris diffinis, are two closely related moths that are highly effective mimics. And while H. diffinis looks very much like a bumblebee, H. thysbe goes it one further. Look at the dull green head and white furry "throat" of the moth, and compare it to the hummingbird -- it's a dead ringer for the female ruby-throated hummingbird, Archilochus colubris. Any predator on the lookout for a meal could easily see the moth, think "hummingbird," and move on. But the moth is completely edible.
It is very hard to tell these animals apart in the field, but one reliable difference is that the hummingbird has a fluid, flexible body and seems to "flow" in flight, while the moth is very uni-directional and a bit mechanical in flight. If you can get close enough, you might notice that the moth has a long, flexible "feeding tube" (proboscis), while the hummingbird feeds with a thin, fixed beak.
With only these small differences separating them, it's understandable that plenty of people see a hummingbird moth and come away thinking they've just seen an actual hummingbird.
This is the bee:
And this is the moth:
Not Bird Nor Bee, but Moth...
This is Hemaris diffinis, a bumblebee mimic that's very closely related to the hummingbird moth above. Both are "sphinx moths," because some of the caterpillars in the group rear up when disturbed, and then they look a little like the Sphinx that guards the pyramids in Egypt. H. thysbe is a great bird mimic, but H. diffinis is arguably an even better bumblebee mimic.
As we mentioned above, yellow and black stripes are a universal warning design that you see on many stinging or otherwise "protected" insects. It follows that some harmless insects will try to look like those dangerous species in order to gain some protection as well. This is the heart of mimicry, and some mimics are astoundingly accurate copies of the original.
The bumblebee moth is one such insect. Although it's a moth and therefore completely harmless and defenseless, it looks exactly like a bumblebee -- it even flies during the day, when most moths are resting out of sight. Surrounded by real bees, it blends in perfectly. Almost the only way to discern H. diffinis from its bumblebee model is to watch it as if flies: bumblebees land on the flower and often crawl into it in order to take nectar from deep inside, but H. diffinis never lands on the flower. Instead it hovers in front and extend a long, straw-like tongue (proboscis) into the heart of the flower to draw out nectar. This is also true of the hummingbird moth.
Watch a Hummingbird Sphinx Moth in Flight
Have you ever seen a hummingbird or bumblebee sphinx moth?
The Thistledown Velvet Ant
Fluff or Ant?
This next mimic adds a truly unique twist to the tactic of looking like something you're not. The female thistledown velvet ant, Dasymutilla species, has evolved long white setae, or hairs, that give the insect the appearance of a tuft of thistle fluff. When the ant is moving on the ground, it bears a striking resemblance to a bit of down being blown along by the breeze. Predators are likely fooled by the insect's resemblance to something that most frogs or birds don't relish eating. The ant's camouflage is even more remarkable when you consider that nearly all the other members of its subfamily (the velvet ants) are brightly colored with the typical red or yellow warning colors.
Why warning colors, you ask? Well, it turns out that the thistledown ant is also protected by one of the most painful stings in the animal kingdom. One common name for the family Mutillidae, other than velvet ants, is "cow killer." That's because these little guys pack a sting that, according to folklore, is so powerful it can kill a cow. Have any cows ever been killed by a cow killer? That's a good question, but it's doubtful. Still, the velvet ant's sting is on the list of the top 10 painful stings in the world!
Well, wait a minute, you may be saying. If the thistledown ant is protected by such a powerful sting, then why does it have to look like a bit of fluff? Why not look like all of its bothers and sisters and advertise its sting with bright reds and oranges? The answer likely lies in a predator that has either learned to handle the ant without getting stung, or have evolved an immunity to the ant's sting -- necessitating another line of defense from the ant.
One of the thistledown ant's nearest relatives
Now You Try: Fluff or Ant?
Which Is It?
One Last Bit of Trickery...
The truth is, the thistledown ant isn't an ant at all -- it's a wingless wasp! All of the "ants" in the family Mutillidae are really wasps with wingless females and winged males (illustrated at right). When you see one with wings, you really realize that it looks like a wasp, after all. And that makes the thistledown ant just a little bit more strange.
Papilio Cresphontes Caterpillar
Would You Eat This?
Even if you were a hungry bird, the answer is probably "no." It looks too much like something that was just deposited onto a leaf. And yet this unappetizing blob is actually a perfectly edible caterpillar, just packed with healthy fats and proteins.
The larva of the Papilio cresphontes butterfly, also known as the giant swallowtail, is a familiar sight in some citrus-growing parts of the country, where it's known as the "orange dog." It feeds, you guessed it, on the leaves of citrus trees, especially orange but also lemon trees. It can get pretty large, about the size of an adult's little finger. When it's time to metamorphosize into a butterfly, it becomes a chrysalis that is also well-disguised, but in a less icky way -- it looks just like a dried up leaf hanging on a twig.
The Giant Swallowtail
That unappetizing caterpillar makes a truly impressive butterfly, one of the largest in North America. The giant swallowtail ranges from Mexico northward all the way to Canada, where it is a rare but regular visitor. It's a member of the swallowtail family, a very large group whose members include some of the most rare and endangered butterflies in the world.
Here's another way that Papilio cresphontes protects itself:
It can stick out a red forked "tongue" like a snake!
AND that forked tongue-thing smells like rotten fruit.
It's no wonder that this species is among the most successful butterflies in a wide range of habitats: it's protected with several "fail-safe" methods that all give it a fighting chance in an encounter with a predator. That red-forked organ is called an "osmeterium" and all swallowtail caterpillars have one. It pops out from a fold behind the caterpillar's head.
Have a look:
Giant Swallowtail caterpillar showing its osmeterium:
Papilio cresphontes isn't the only one...
The larva of the black swallowtail, as well as many others, resembles a bird poop, but only in its early instars. After it sheds its skin a few times, it takes on a lovely -- and perfectly camouflaged -- green and black striped skin. It feeds on carrots and dill, and can be nearly impossible to see once it moves past the bird-poop phase. The chrysalis, like the giant swallowtail's, closely resembles a bit of dead twig or leaf.
Bates and Muller -- The Two Top Names in Mimicry
Mimicry among all animals can be classified according to the actual physical characteristics of the species involved as well as their interrelationships. The harmless fly that mimics that stinging hornet is a good example of what's known as Batesian mimicry. Henry Walter Bates roamed the Amazon rainforest in the middle of the 19th century, collecting and recording hundreds of butterfly species while coping with illness, suspicious locals, and an inhospitable environment. His pioneering work helped Western science understand the insects of the New World, and his influence on zoology in general really can't be exaggerated.
One of the things Bates uncovered was vast networks of butterflies that all seemed to resemble one another, even though they weren't evidently related, He came to suspect that they were all involved in mimicry relationships, and that there were edible species that mimicked poisonous ones. In other words, harmless insect species had evolved to look like toxic ones -- a sheep in wolf's clothing. This pattern become known as Batesian mimicry.
The Mimicry Story -- An Unexpected Twist!
But Bates soon realized that some toxic species looked exactly alike. Bates himself realized this was part of the mimicry story, but he wasn't sure what to make of it. Why would would two toxic, unrelated species evolve to look exactly alike? What was the benefit?
Models on the Left, Mimics on the Right
Bates was puzzled by groups of butterflies that were all protected by being distasteful to predators, and yet shared the same bright colors and patterns. These warning colors, known as "aposomatic" signals that warned predators not to even try taking a bite, were often identical, even between species not closely related to each other.
The German naturalist Fritz Muller came up with a possible answer: if a bird or lizard was confused by two or more butterflies with similar warning colors, then both insects would benefit -- the predator would leave them both alone, and as a result neither insect would be the victim in a potentially fatal experiment by a hungry lizard or bird. The shared association, in other words, was beneficial to both. Plus, Muller argued, in this case mimicry worked both ways. The predator was also protected, since it was dissuaded from getting a mouthful of some very nasty insect parts.
As it turns out, there was a prime example of Mullerian mimicry under everyone's noses, and no one realized it: the monarch/viceroy butterfly relationship. Everyone assumed the toxic monarch was the model in a Batesian mimicry relationship with the edible, unrelated viceroy butterfly. In the 1990s however, that was turned upside down when it was discovered that the viceroy was actually more toxic than the monarch. The relationship went from Batesian to Mullerian overnight!
The Ant Mimic Spider
This one is pretty amazing -- Myrmarachne plataleoides
In the forests of Southeast Asia lives a spider that looks nothing like a spider. Instead, Myrmarachne plataleoides, a spider also known as "the Karengga Ant-like Jumper," looks exactly like an ant. It even disguises the fact that it has eight legs instead of six by waving its extra legs around exactly like antennae. The spider doesn't bite and is quite shy, but the ants that it copies are well-known for their sting and their willingness to attack intruders. This peaceful and harmless little spider gains a great deal of protection from being a mimic.
A Weaver Ant -- not someone you want to mess with!
The specific ant model for this mimic is a common insect known as the weaver ant. It's in the genus Oecophylla, and, like all ants, is closely related to wasps and bees. Not all ants sting, but nearly all of them are protected in some way, whether by bite, noxious chemicals, or the power of numbers. While weaver ants don't have a powerful sting, they do have powerful jaws, and they can bite ferociously; in addition, they often spray formic acid into the bite, which in essence makes it a venomous sting. They are known for defending their nests against all intruders great and small, and some farmers in Asia have been known to use weaver ants as a pest control measure by importing colonies into their fields.
This is the spider:
And this is the ant:
The Weaver Ant and Its Spider Mimic -- Side by Side
Weaver ant mimic spiders look so much like a weaver ant that even the ants get confused around it -- normally they would be expected to attack anything that dared to come close to their nest, but the spider stays quite close, even blending in with the ants. Part of the spider's secret is the adaptations of its body parts. Insects have three body sections, the head, abdomen and thorax. Spiders, on the other hand, have only two, the big abdomen and the smaller cephalothorax, which is basically a combined head and thorax section. In M. plataleoides, the abdomen is elongated and features a series of strictures that effectively mimic the ant's slender waist and multiple segments. In addition, the spider's head is the same size and shape as the ants, and it even has two black markings that precisely mimic the ant's eyes -- that's right, the ant's eyes are real and the spiders are just two black marks. The spider's real eyes are small, and there are eight of them.
But is just gets weirder. The spider is sexually dimorphic, which means the male and females look somewhat different. In this case, the male has extremely elongated chelicerae, which are fang-bearing mouthparts, that stick way out in front of them. They serve two functions -- the first is to fight with other male spiders, but the second is pretty amazing. The chelicerae, like the spider's head, have two black smudges that make it look like a weaver ant head. But why would the spider want to have two fake ant heads? Isn't one enough?
Two Ants in One!
It turns out that weaver ants often carry smaller ("minor") weaver ants around in their jaws. It's hard to believe, but male M. plataleoides don't just mimic one ant, they mimic two -- one ant carrying a second one around in its jaws. And when needed, they can split that fake head apart, revealing serious fanged jaws for fighting or grabbing prey. Truly an amazing adaptation.
And these mimic spiders don't just look like weaver ants -- they also act like them. They hang out in the trees and bushes where the ants live. Since they're spiders, and all spiders are predators, they attack and eat small insects in the vicinity of the ant nest. Apparently the spiders also mimic the way the ants walk, and wave their front legs to mimic antennae (thus taking care of the 6-leg vs 8-leg dilemma).
Bonus Mimic: a Moth That Mimics a Spider!
The Viceroy Butterfly
This is perhaps the classic, and certainly the best-known, example of mimicry in the insect world. The monarch (Danaus plexippus) is the aptly-named king of North American butterflies, and nearly everyone has a general idea of what they look like. The caterpillar feeds only on species of milkweed, a common plant that is protected from most insects that would eat it by a poisonous, milky white sap. The monarch, however, has adapted to that strategy. The caterpillar happily eats milkweed leaves, and even incorporates the toxic alkaloids in the sap into its own tissue -- in other words, it becomes toxic, just like the plant it feeds on. This happens quite often in the insect world.
Since the caterpillar is toxic, the butterfly is also known to be distasteful to predators like birds. Over time, birds have modified their behavior to include the avoidance of bright orange and black butterflies. As a result, Batesian mimicry complexes exist throughout the range of the monarch -- butterflies that are otherwise completely edible to birds have evolved, and likely are constantly evolving, to look more like monarchs. This is the essence of this kind of mimicry: look poisonous or dangerous, even though you're not.
The viceroy, Limenitis archippus, a butterfly unrelated to the monarch, has evolved markings that are almost identical to the monarch. We're not talking about a vague resemblance -- this is a down-to-the-details replication of the monarch's wing pattern. Have a look:
Monarch on the Left; Viceroy on the Right
Pretty amazing, right? And it's even more so when you know that the viceroy's relatives are all black or dark blue butterflies, and the caterpillar of the viceroy isn't even close to the monarch.
For a long time, it was assumed that this was a case of Batesian mimicry -- the poisonous monarch and its perfectly edible copycat. In the 1990s, though, studies concluded that the viceroy is actually the more poisonous of the two! That means that these species are involved in Mullerian, not Batesian, mimicry: two poisonous species that look like each other to the benefit of both.
The Snake Caterpillar
There are quite a few caterpillars out there that sport eye-spots in an effort to look like something they aren't. These caterpillars are completely harmless, but the big fake eyes they have -- the better to eat you with! -- might fool a hungry bird or lizard into thinking twice. Of the caterpillars that look like a miniature snake, there are some in North America -- the spicebush swallowtail, for example -- that are pretty good at what they do. But none of them can touch the amazing snakiness of one of the natural world's most accomplished mimics, Hemeroplanes triptolemus, aka the snake caterpillar.
What you're looking at here is the underside of the caterpillar's head and first few segments. When threatened, it twists its front half upside down and inflates the area around its head. This reveals bright "eyes," complete with super-realistic details like light reflections. If you look closely, you can see the caterpillar's six legs folded tightly against its body -- look in the dark area, right where the snake's "nose" would be. The caterpillar's head is in the pale area where the snake's "lower lip" is located. Even when you know where to look, it can be hard to see these features of the larva.
As if the camouflage wasn't enough, the caterpillar will sometimes strike like a snake at threatening predators. It's harmless, of course, but if you're a frog or a lizard thinking about making this animal its lunch, you might decide not to risk it.
Here are some more pictures:
The snake-mimic caterpillar turns into a handsome, though unspectacular, moth. It's in the sphinx family and is related to tomato hornworms and many other species.
The Adult Moth of Hemeroplanes triptolemus
Here's a video of a closely related snake-mimic caterpillar from Indonesia:
The Leafwing Butterfly
Blending in with the scenery is a very common trait among insects and animals in general. Whether you're a tiger preparing to pounce on your prey, or a grasshopper trying to avoid being seen by a toad, you're going to want to avoid being seen. This is commonly called "cryptic coloration" and hardly any group of animals doesn't use the tactic to some degree.
Some butterflies raise cryptic coloration to an art form. There are some butterflies out there with wings that look so much like dead leaves that even experienced naturalists pass them right by. Some even include markings that mimic damage caused by insects or decay -- among these is Coenophlebia archidona, a rainforest species uses its cryptic underside to escape being noticed by predators.
Coenophlebia archidona -- Great Leafwing Photo from a Great Butterfly Site
Learn About Butterflies is a good site with some really amazing photos. Highly recommended.
The Ladybug Spider
We have already seen how a species of spider mimics the hard-biting weaver ant in order to gain protection. Here's another spider that is also pretending to be something it isn't, but its purpose is a little less innocuous. Spiders in the genus Eresus are beautiful mimics of ladybugs, but not so they'll just look pretty -- one reason may be so they can sneak up on their unwitting prey. This strategy is the reverse of the ant-mimic spider, which mimics a dangerous species to be left alone.
Eresus spiders, like all spiders, are predators that feed on smaller insects and other groups. Many spin webs, but many others simply prowl around looking for smaller insects to ambush.
Ladybug Spider, Yellow Version
Paraplectana tsushimensis -- the Ladybug Spider
The genus Paraplectana is relatively new -- it was first described in 1960 -- and it includes some remarkable organisms. Among them are the ladybug mimic spiders, though there is relatively little written about them and images are scarce on the internet. It's safe to assume that they're predators, since all spiders are, but questions remain. Ladybugs are known to contain bad-tasting chemicals that they "bleed" from specialized pores when they are threatened, so Is the ladybug disguise meant to deter predators? Or is it used as a stealth attack mechanism that allows the spider access to populations of unsuspecting prey species?
Much more has yet to be learned about this fascinating animal.
The Owl Butterfly
Owl Butterflies in the Caligo Genus
In the deep shade of the rainforest throughout the American topics, these gigantic butterflies can sometimes be seen flapping away among the trees. It may be more accurate to speak of these big creatures being felt rather than seen, since making them out among the shadows is often difficult. Entomologists who study this group typically set up traps baited with rotten bananas, and it's not uncommon to find a half dozen or more feeding on the bait. It's quite a moment to arrive at a patch of bait and find a group like this!
Owl butterflies get their common name from the resemblance of the giant eyespots on the hind wings to the eyes of an owl. Those eyespots are so realistic that prey animals like birds and snakes may be startled long enough for the insect to make its escape. They're so realistic, in fact, that it may be hard to remember that they can't actually see, and are just arrangements of pigmented scales.
The Caligo Owl Butterflies
These enormous butterflies are widespread throughout Central and South America. The larvae feed on palm and other rainforest trees, and they are amazingly cryptic when they rest on a leaf. The butterflies are typically dull gray or blue on the upper side, but some have bright yellows and purples. In nearly all of them, there are well-developed eyespot markings on the underside, set against a background of fine brown striping that allows the eyespot to stand out.