On his website Evolving Perspectives, Reader Pliny the In Between—perhaps inspired by yesterday’s posts on mimicry and Alabama’s banning of sex toys—has created this nice cartoon that he calls “Batesian mimicry”.
A biological digression:
Now if you don’t understand the title, Batesian mimicry is an evolutionary phenomenon whereby a conspicuously colored or patterned toxic individual, called a “model,” is avoided by its predator, who has learned to avoid the pattern lest it be stung, bitten, or poisoned. (The learning predator is called the “signal receiver”.) Many conspicuously colored insects, for example, like ladybird beetles (“ladybugs”) or monarch butterflies, are brightly colored and patterned because they are toxic and distasteful. It’s a bit of a mystery how these warning colors and patterns (called “aposematic”) evolved, since the first conspicuous mutant, even if toxic or distasteful, would call attention to itself (the predators hadn’t year learned), risking a higher chance of being attacked. One possible solution is kin selection.
Nevertheless, once the model has evolved aposematism, and there are predators who have learned to avoid it, then there is an evolutionary advantage for a nontoxic species (called a “mimic”) to evolve a resemblance to the model, thereby gaining respite from predation based on the predator’s learned avoidance.
The phenomenon was named after the British naturalist and explorer H. W. Bates (1825-1892), who, in his travels in South America, saw such mimics and devised the correct evolutionary explanation. He, like his co-explorer Alfred Russel Wallace (with whom Bates traveled in 1848), was a great fan and promoter of Darwin’s theories of evolution and natural selection. In fact, Batesian mimicry served as some of the earliest evidence for natural selection, as the system is easily explained by natural selection while creationists are forced to concoct ad hoc arguments.
Here’s a good example of a Batesian mimic: a moth, perfectly edible to birds, that is avoided because it resembles a hornet. I was once fooled by a similar moth that invaded my home in Maryland. This one is Sesia apiformis, taken from the UK Moths website:
You’d avoid that if you saw it, wouldn’t you?
Pliny cleverly called his cartoon “Batesian mimicry” because the pair of women “proselytizers” are, while mimicking the unpalatable pairs of Mormons or Jehovah’s Witnesses who visit homes, actually quite innocuous themselves.
Yes, I’d avoid that moth but then I’d come back and see the weird little antennae then the odd face & I’d poke it with a stick a little to see what it did. 🙂
On Friday’s walk in South Mountain Park with Baihu, for quite a stretch there was something that made me think it had a stinger that kept circling my head, though I never got a good look at it. I don’t know if it actually had a stinger, but its yellowish (I think) coloration, the sound of its wings, and its flight pattern was enough to convince me that I didn’t want to start swatting at it. It could, I suppose (and thought at the time) have been some sort of a fly, but it wasn’t worth taking the chance.
This was along a ridge, and, when the wind picked up at a high point, we seem to have left the wee beastie behind.
But the valley below, when we got there, was quite loudly humming with what almost had to have been bees in the blooming palo verde trees, though none of the trees were close enough to the trail to see what was actually making the sound.
So, yes, I’d avoid that moth. No question.
b&
I saw something recently that I think is quite interesting considering how upfront they are on their methods of indoctrination:
“My Obligation to Grace Church as a Member
• I have read and understand the Grace Church doctrinal statement and will not be divisive to its teaching. I also understand the importance of submission to church leadership and will be diligent to preserve unity and
peace”
That’s from a group called Grace Church Seattle: http://storage.cloversites.com/gracechurch8/documents/Grace_membership_covenant_March2011.pdf
If you read through their membership covenant, you get the very real impression they’re unashamed at the psychological manipulation techniques they’re engaging in. And the more I’ve looked into the issue, the more I see they’re one of many groups operating using the same tactics.
I’m not sure how the mimicry would work in the case of the rationalist proselytizers — it would not be advantageous to have the door slammed because you’re thought to be one of “those” creepy beings. If harmless, you’d want to be clearly seen as such, no?
The moth is semi-familiar to me as we have a couple of roughly similar species of clear-winged moths here in Calif. I would immediately recognize it as a fake wasp — but these moths have wood-boring larvae and the most common one around here is a menace to peach and plum trees. If I were a peach perhaps I’d be more nervous.
I don’t get it: are we supposed to treat those two as we would Jehovah’s Witnesses?
I suppose you have to first put yourself in the position of a typical householder. Readers of WEIT are not typical: from what I know, a high proportion of American householders would be much more likely to slam the door on someone wishing to talk to them about consensual but non-orthodox sexual relationships than on someone wishing to talk to them about ‘saving their immortal souls’ or other such religious woo. Given this is the case the joke that someone wanting to promote tolerance of other people’s sexual preferences should mimic a Jehovah’s Witness makes perfect sense.
I think the joke is funny.
You are correct sir.
I don’t think I would avoid those two fake-Mormons. I’d invite them in for a nice long chat, especially about consensual sex.
Yeah, I was thinking something like that too. Why, oh why, don’t the Mormons take the obvious line and send out their young women to proselytize instead of the men. Is it because they’re already kept barefoot, pregnant and chained to the kitchen sink?
They sure do send women.
The only reason there aren’t as many female missionaries as there are male is that it’s up to the young adult to decide to become a missionary, and fewer females decide to do so because of tradition.
But there is no active discouragement of female missionaries by the church authorities.
Hmmm, never seen one on this side of the Pond.
Then again, I did once swear the Morons off the property from down in the cellar – I was doing the plumbing for putting heating into the bedrooms IIRC – so I didn’t actually check genders on that occasions. I just heard the burbling stream of bullshit coming through the letterbox and tore into them on autopilot.
lol
I wish our Mormon visitors would ask this question. And wouldn’t it be nice to have saffron clad Moonies in airports asking for a donation to help educate the public about the benefits of vaccination? Maybe in some other place in our multiverse…
Reblogged this on The Road.
If ladybirds became colourful in one step, before predators recognized the markings, then that wouldn’t be advantageous. But, perhaps the first poisonous individuals would not have had such distinct markings, so that predators might *sometimes* mistake them for something else. Then it would be an evolutionary advantage to gradually reinforce the particular distinctive marks in successive generations of that species so that the predators made less mistakes.
I think that’s the right answer. And, there are other species of ladybird beetles that are not aposematic/red — but I don’t know if they’re distasteful/toxic. Maybe they are and that’s the foundation.
I was thinking along similar lines. Toxicity comes first, but so what, predators have got to know you’re toxic. Admittedly, the first few toxic insects with recognisable markings would be even more likely to be eaten than their duller kin, but, just the same, a few of the toxicos would have laid their eggs before being eaten.
The survival of the next generation is helped by their predators’ unpleasant experience with the insects’ toxic parents – and so on, down the generations.
The other ladybird beetles I’m aware of that are not red are shiny tan with dark spots. They’re still fairly cryptic at a distance, but probably recognizable at close range. I can imagine how natural selection could build on that.
I too wondered about this mystery of batesian colours.
I guess one problem with the theory offered above, whereby toxicity and learned behaviour are there in the first place and conspicious markings follow, is that the birds (or frogs or whatever) could in the early stages very badly distinguish between toxic and nontoxic species, and therefore not learn. So we’re back where being more conspicious is of disadvantage first.
But what if the warning pattern evolves by selection pressure from another sort of predator, who is getting to “taste” the prey before seriously injuring it, like ants? And if that outweighs the disadvantage of being more conspicious to things like birds and frogs?
I’m wary though about deeming myself smarter than half a dozen generations of biologists, and would be seriously interested what has made this question unanswerable for so long.
Another thing I can’t quite get my head around is how you can arrive at toxicity by gradual steps, anyway. If you’re only rudimentally toxic and get killed without making your predator uncomfortable, how can it accumulate by natural selection? Does high toxicity arrive spontaneously by mutation?
I wonder if we aren’t concentrating too much on the visual cues and potentially ignoring other senses such as smell. It isn’t hard to imagine that toxins (even those of intermediate potency) might alter this enough for a predator to pick it up at short range at least reducing predation during the terminal phase of an attack. Perhaps the co-evolution of coloration came later as a means to ward off attack at longer ranges.
As JAC pointed out kin selection provides one possible route by which aposematism could arise. If I get eaten but my siblings all survive because the predator has learnt that indivduals that look like me are foul tasting then the trait can be spread.
Another aspect is that aposematism does not necessarily require that the aposematic animal gets killed and eaten. Wasps may sting without themselves being killed, bombardier beetles squirt toxic gases and live to fight another day and skunks likewise can survive their encounter with a potential predator who learns that distinctive black and white stripey critters are best avoided.
The problem with the kin selection argument is that the kin of a single individual with a poison mutation would only be a very small part of the total population that is being predated. Birds aren’t going to stop eating you just because a tiny proportion of individuals, that other birds have sampled, gave them a belly ache.
Tasting unpleasant would not necessarily be directly linked to colouration. For instance, if it evolved for some other reason than protection: If I was forced to eat a beetle, I probably wouldn’t choose a dung beetle. And once tasting unpleasant has been established in a significant proportion of the population, then any markings that enhance the recognition of that species, would be a selective advantage to individuals.
This is almost certainly the case in newts. All salamandrids are toxic and all of them have varying degrees of aposematic coloration, with a handful of species which have virtually none. However, their skin secretions are both visible as a milky substance and very smelly regardless of their coloration and level of toxicity. If they stink to us i can´t imagine what a predator with a keen nose would think of the foulness of a newt or fire salamander covered in those toxins.
They not only use aposematic colours (quite spectacularly so, by the way, newts are cool) and foul chemical smells, but also posture (Unken reflex). This happens in other amphibians too.
Forgot to add that their milky toxic secretions are rather conspicuous even if the animal itself isn´t. Much the same way a ladybird´s secretions are conspicuous and smelly. The animal wouldn´t have to be, initially so long as its secretion is both of those things. Then you could build on the coloration, generation by generation so that the warning extends its range.
This reminds me that we should not ignore the process of natural selection operating on the predators. Specifically, it will be a significant advantage to them to be able to tell toxic from non-toxic prey. We would expect that the predators who pay attention to whatever physical differences there are between toxic and nontoxic critters would have more kids. This would in turn create the evolutionary advantage of looking different for the prey.
I don’t think most ladybirds are toxic to the extent that they would do predators fatal harm, they just don’t taste very nice.
I myself would not eat that moth.
A parody of this one comes to us all from Mr Dan Piraro / Bizarro circa June 2007, … …
ak.pinterest.com/pin/284149057713279204
which I liked so much that I made it into a laminated door placard.
It has been greeting all folks at my front door now for about five years’ time.
Blue
Wait, you weren’t tricked by a hummingbird moth, were you? Well, I guess they kind of do look like bees from the wrong angle.
Great cartoon!
I actually enjoy engaging the door to door religious folks sometimes if I have time. The last time I had a Jehovah’s Witness married couple and after a little chat told them – yes, I’d be happy to look at their literature IF they agreed to take and read mine, which was Sam Harris’s Letter to a Christian Nation. Got a big No-Thanks!…but worth a try.
Yes, I’ve had a few nice chats with JWs and Mormons.
The Mormons are the more interesting, if only because they’re better educated. But, they clearly don’t usually encounter people like me and have never been exposed to some of the ideas I hold. Someday I’ll convert one, on my own doorstep! Maybe even a twofer.