More cool mimicry: a ladybug-mimicking spider

August 20, 2012 • 4:41 am

From the Flicker page of Nicky Bay, a photographer from Singapore, we have this beautiful example of mimicry: a spider (not an insect) mimicking a ladybug (“ladybird beetle” to Brits, which is actually more accurate since these insects are members of the order Coleoptera—beetles—rather than that of the “true bugs”, Hemiptera).

Screen shot 2013-08-04 at 5.24.25 AM
Photo by Nicky Bay (used with permission)

Ladybugs are brightly colored with what we biologists call aposematic (“warning”) coloration: a warning to predators to avoid them because they’re bad tasting (ladybugs contain toxic and foul-tasting alkaloids).  Such coloration is common: other examples include black-and-orange striped bees and wasps, the orange-and-black monarch butterfly, and the striking pattern of the noxious striped skunk. (I once had a pet striped skunk for several years—descented, of course. It was a lovely animal, bred in captivity, tame, loving and litter-box trained, but I still feel a bit bad about having a pet whose genome was adapted to living in the wild.)

Once an aposematic model species is in place, there is an advantage to tasty and nontoxic species to evolve the patterns and colors of the model, for by so doing they avoid predation.  This form of imitation is called Batesian mimicry after the British naturalist H.W. Bates. Here’s one example of a model (this one American) which the spider is likely imitating:

Ladybug at Frozen Head State Park in eastern Tennessee. Photo © Wade Franklin
on Flickr: http://www.flickr.com/photos/w_franklin/481357492/

There’s no problem in explaining the evolution of Batesian mimicry, but how aposematic coloration evolved in the models has always been an evolutionary puzzle.

The system works now because predators learn to recognize and avoid the bright coloration after a bad experience tasting the prey (predators may occasionally evolve an innate, genetically-based aversion).  But imagine the first mutant ladybug that is somewhat brightly colored. It won’t be avoided by bird predators because they’ve had no experience with the coloration, and will stick out because its color is conspicuous. This mutant individual may attract the attention of predators, and thus be more likely to be eaten than less-colorful individuals in the same species. In other words, natural selection would seem to work against the initial evolution of such colors, even though individuals benefit once the pattern becomes common. But how does it get to be common?

One suggestion is kin selection: mutant individuals may occur in broods of relatives, so an individual “sacrifices” its life to perpetuate the colorful genes of its brothers and sisters, now presumably protected by a bird that’s learned its lesson. And indeed, some aposematic caterpillars tend to stay together as groups of relatives more often than individuals of related species that aren’t colorful.  But other evolutionary models show that the bright color could result from individual selection, particularly if the colorful individual isn’t really killed, but only tasted and released.  There are other, more complicated models as well. For the time being, the evolution of such coloration remains a bit of a mystery.

And here’s a video showing another “ladybug spider”; I’m not sure if it’s the same species.

Here, from the website “What’s that bug?” is another example of what is likely to be a Batesian mimetic spider.

I found it on Arkive as well; it appears to be a rare, sexually dimorphic species in which the males are Batesian mimics and the females, much larger, aren’t. Here are both sexes with an egg case.

The attractive ladybird spider (Eresus sandaliatus) is one of the rarest in the UK. The males have a bright orange or vermilion back with four large black spots and two smaller ones, and superficially resemble a ladybird. Females and juvenile males are black and velvety. Both sexes and immature individuals have obvious large bulbous heads. Photograph by David Fox.

37 thoughts on “More cool mimicry: a ladybug-mimicking spider

  1. Or…maybe the neither are mimicking each other and both were both always this way. It’s amazing how supposed scientists will never admit that anything is a brand new discovery (for them) of which they know nothing about–they’ll just make facts and absolutes up to try to always appear, “all knowing.”

    This discovery also fails to prove “Why evolution is true.”

    1. Please educate yourself on Batesian Mimicry (http://en.wikipedia.org/wiki/Batesian_mimic If you’ve got a problem with Wikipedia then read the references) and then explain how YOU think these particular patterns evolved this way. After all, these “so called scientists” have studied this phenomena for a very long time and I would be interested how all these silly people came up with such a wrong idea. Methinks you are simply ignorant and keen on making a fool of yourself.

      I have a feeling I know what your answer will be. Be prepared to provide evidence.

      1. “Please educate yourself on Batesian Mimicry (http://en.wikipedia.org/wiki/Batesian_mimic

        Methinks you are simply ignorant and keen on making a fool of yourself.”

        How does this and your ad hominem prove anything?

        I’m well aware that Batesian Mimicry was mentioned in the post and anyone with half a brain can figure out what it is supposed to be. Telling me that someone from pre-Civil War 19th century came up with this idea fails to impress considering how limited their their scientific knowledge was back then (Christian friar Gregor Mendel did not even produce his findings on genetics yet). And it fails to give the assertion any validity.

        Here’s something else from Wikipedia (not in the least bit surprising):

        “Perhaps one of the most well-known examples of mimicry, the viceroy butterfly (top) appears very similar to the noxious tasting monarch butterfly (bottom). Although it was for a long time purported to be an example of Batesian mimicry, it has RECENTLY BEEN DISCOVERED that the viceroy is actually more unpalatable than the monarch, making this a case of Müllerian mimicry.”

        LOL! Oops–we were WRONG all this time! Are we going to learn from this and use language from now on admitting that we are unsure? Of course not!

        There is a whole world out there that we know little about. To the native peoples of other parts of the world, the ladybug would be a “new discovery” that looks a lot like THEIR own colorful arachnids that could be so colored because of their chemical composition, because they ARE unpalatable to many of their predators, because there are poisonous and/or harmless plants or other arachnid or insect species that look a lot like this, or a number of other unknown reasons. But I have the feeling that instead of taking an arrogant (and likely ignorant) stance and asserting that the ladybug is mimicking an arachnid that is millions of miles away, these native peoples would simply conclude that there are creatures in different parts of the world that share surprisingly similar traits. And they would be 100% correct.

        1. Oh dear – “there are creatures in different parts of the world that share surprisingly similar traits” precisely because they share a common ancestor, & are worked on by the process of natural selection. A much simpler explanation than that the gods people create did it.

            1. Pointing out that a certain observation can be explained by evolution, and therefore supports the theory of evolution, is not a logical fallacy.

              1. And how do you explain black, brown, and white ladybugs? Seems the supposedly scientific assertion that it’s a protective evolutionary trait developed via natural selection is BS.

              2. Shifting the goal posts, are we?

                The nice thing about a good theory is that you can test it. In this instance, you could collect a few thousand ladybugs. You paint half of them, say, light blue, and don’t touch the others. Then watch how well the blue ones survive relative to the normal ones.

                In other words, it would take some research to answer your questions. There is no holy book in which we can look up the answers.

              3. I could also point out that beetles that live underground or in caves never have bright colours. Why would that be?

                Easily explained by evolution; not so easy to explain by special creation.

              4. “I could also point out that beetles that live underground or in caves never have bright colours. Why would that be?”

                For the same reason that you don’t see brightly colored flowers in caves–lack of sunlight.

                Is it that hard to believe that ladybugs could have been designed with such uniquely protective mechanisms (such as bright coloring) because their numbers are a lot fewer in relation to many other insects? Thus maintaining the proper–and essential–ecological balance? Compare the number of insects (such lacewings, grasshoppers, crickets, gnats and other “pests” that enter into your home from your yard) and compare that to the number of ladybugs that enter your home and you will note something obvious: ladybugs with their bright coloring have gained no advantage whatsoever over other insects. But even though their numbers are fewer, their numbers are just enough to play their integral part in the ecosystem by doing what precisely what they were designed to do: keep the number of other more highly reproductive insect populations (also an integral part of the ecosystem) from getting out of hand. Amazing and miraculous, isn’t it?

              5. For the same reason that you don’t see brightly colored flowers in caves–lack of sunlight.

                That’s just nonsense. Unlike (almost all) flowering plants, beetles don’t need sunlight. Your god could easily have created cave-dwelling beetles with psychedelic colours. Why didn’t he?

                As for the rest of your reply, I suggest that you read a textbook on population biology. You will then be able to grasp that the number of ladybugs is limited by their food source, number of predators, parasites, etc. There are countless less conspicuous insect species that are much more rare than ladybugs. Also note that looking like a ladybug is only one of many ways insects have evolved to avoid being eaten. Many rely on camouflage, speed, etc. You will have noticed that ladybugs are rather slow and much easier to catch than most other beetles. Why would that be?

    2. I know from reading various posts you’ve made around the blogosphere that you are a creationist

      In one interesting thread a poster asks:- “Out of curiosity, what books or sources does your understanding of evolution come from?”
      Your reply was:- “I was inculcated with evolutionary doctrine in school as most are/were”

      SOURCE

      Am I to take it that you have not read WEIT & that you have no interest in doing so?

        1. The book Why Evolution is True, & any number of others based on EVIDENCE & careful OBSERVATION. Not a silly made up sky fairy book.

  2. Imagine if the aposematic coloration evolved as a post-reproductive mechanism, for which an individual was able to sacrifice themselves for their offspring. Wouldn’t take long for the aversion of predators to their color be fedback into the development of a juvenile trait, perhaps increasing the probability of survival to maturity.

  3. Inferring kin selection seems to be over-complicating the ‘problem’. Imagine a group of toxic beetles. Predators learn or evolve to avoid these prey, but not with 100% accuracy as they look similar to other edible species. A slightly more exaggerated, brightly coloured mutant may, in fact, be MORE recognisable as the toxic species (see ‘superstimuli’)and therefore this initial mutation may be advantageous after all. Thus no necessity of kin selection (and thus the large brood sizes and limited dispersal that it would imply).

  4. Is it not possible that the mutation appears not in one individual, but in the whole brood of a mutated parent? That way you get quite a large number of individuals. If there is on a 1% survival advantage, that will soon see the trait/s spread in a population? If the mutation is recessive, as long as the gene remains hidden by dominant genes we will not see its effect, but eventually two descendants will mate & the gene will be expressed – then again, even a slight survival advantage will see there are more surviving offspring. At some point then surely the dominant trait will die out, leaving a changed population?

  5. You start with an animal that has learned how to taste bad and its predators have learned to dislike it. Then the more distinctive they are the less likely any of them are to be eaten. Gradual change is important because because then they all look sufficiently similar to be recognisable to predators, but the more brightly coloured ones are less likely to be eaten by accident.

    1. I’m sure you’re right (my comment 1 is a feeble infinite-regress joke).

      Bad tasting insects need not die when they are taken i to a predator’s mouth – I think ladybird’s secrete the nastiness. So it’s selective at the individual level.

      Also, LB’s lay clumps of eggs, and the larvae have the warning coloration – a clear opportunity for kin selection (larvae can’t fly off to another bush, so there’s immediate feedback if a predator eats a larva).

      There are ample opportunities for Darwinism.

  6. A Brit, I have always just called it a ‘ladybird’, not a ‘ladybird beetle’… =D

    They were among the first delightful finds of a childhood of long, happy summers dreamed away on the edge of a Devonshire wood. I remember them adorning both the cat and the strawberry plants. In later years I have encountered literal drifts of them outside the doors of astronomical observatories on Mauna Kea, Hawaii, at elevations approaching 14,000 ft. Poor creatures were properly lethargic – we used to carefully bag them up and take them back to sea-level in Hilo.

    1. The southern Arizona starhenges all have “drifts” of several species of ladybird beetles in summer. Mt. Graham even has a “Ladybug Trail” since it is so common to see thousands of ladybugs covering branches. Spectacular, especially in contrast with the shady, lichen-draped evergreen forest.
      Here’s adybird beetles on Mt. Graham, on Pseudotsuga branch with Gambel oak leaves and Pseudevernia intensa lichen:
      http://www.mineralarts.com/artwork/ladybugbranch.jpg

  7. “‘ladybird beetle’ to Brits, which is actually more accurate since these insects are members of the order Coleoptera—beetles—rather than that of the ‘true bugs’, Hemiptera”

    But though these critters are not bugs, neither are they ladies, nor birds. So you’re pretty much SOL on accurate naming either way. 🙂

  8. Hi

    I have a question. Before I have to admit that I should read more to understand the principles, but here is an idea.

    Because are “bugs”, insects, in these type of classes, you will have at once a hatching of a lot of animals with this colourful pattern on their skins. What happens if one bird eats one and of course it realizes that they are not good? It will not eat the others. So many more are saved. Of course you have a lot of birds, but it is a contest between how many off springs you have, how many can evade predators, and how many birds learnt to avoid them.

    My 2 cents – again, not a biologist

  9. Tidbit: In France, we call Ladybugs “Coccinelles”, and nickname them “bête à bon dieu”. The nickname comes from their tendency to cluster at the feet of “pardons” in the mountains, some type of religious altar for passers-by (the pardons, not the mountains!).

  10. The sad irony is that many of the very people who (rightly) ridicule others who see Jesus on their toast are THEMSELVES guilty of doing the very same thing!

    When they see a spider in another part of the world with a pattern on it’s back that looks a lot like a red ladybug, they lose track of all rational thought and instead of accepting this as a possible and likely coincidence, they scream, “Oh my Darwin, it’s a LADYBUG! That spider is mimicking a LADYBUG–PRAISE natural selection! Proof of GLORIOUS evolution!” (Never mind that there are no ladybugs in the region.)

      1. “That’s just nonsense. Unlike (almost all) flowering plants, beetles don’t need sunlight.”

        Let’s place you in a cave or underground without any artificial light from now on and let’s see how long you retain your color.

        “You will then be able to grasp that the number of ladybugs is limited by their food source, number of predators, parasites, etc.”

        The food source is always in excess of ladybugs–that’s why you can purchase ladybugs in order to expedite the eradication of aphids and other “pests.” Pests that are simply doing their job by assisting in decomposition.

        “Also note that looking like a ladybug is only one of many ways insects have evolved to avoid being eaten.”

        Or maybe the resemblance is simply a COINCIDENCE–just like those images on trees, Doritos, and toast that people swear has to be Jesus. What evidence is there that this is mimicry we are looking at? What’s the justification for such a narrow-minded self-centered conclusion that these other tropical species of arachnids are the ones mimicking the pretty beetles that you find in your yard?

        “You will have noticed that ladybugs are rather slow and much easier to catch than most other beetles. Why would that be?”

        When you diet consists of aphids and mites that feed on disease, decay, waste, and dead matter–that is inevitably going to have an effect on your own chemical composition (which explains their toxicity). And yes, they’re more vulnerable and easier to catch which may be why they are so designed.

          1. YOU are a hopeless case. The author of this post drew these conclusions himself from some random person’s Flicker photos and you just buy whatever is asserted without his ever having to do any ACTUAL RESEARCH–hook, line, and sinker! What an easy, faithful zombie you are–never asking for confirmation, never demanding evidence!

  11. Reblogged this on macrocritters and commented:
    This particular blog isn’t specifically about macro photography, but it does feature some wonderful pictures of some great critters. A ladybug-mimicking spider—how cool is that? It’s a great blog and an interesting read. The comments are fascinating to read too…although a bit like watching a train wreck…

    Cheers,
    EC

Leave a Reply