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Stuff [Aug. 14th, 2012|10:27 pm]

My uncle gets very upset if someone uses the word "creationist", because he's not religious and he agrees that thinking the Earth was created 6000 years ago is stupid. But he is...a person who believes that evolution can't be explained by natural selection of random mutations, and he posits a complicated "guiding force" called "syntropy" which he says opposes entropy by working through quantum mechanics. It's kind of a combination of everything I find philosophically cringeworthy, but to his credit he's done his homework and knows his biology, in much the same way Velikovsky knew his history.

Right now he's writing a book on his theory, which uses many of the anti-Darwinism arguments you would expect - he's a big fan of irreducible complexity even though he doesn't like the term. Every time I talk to him he tells me a little bit about his latest research and we end up getting into a big (but mostly good-natured) argument.

The last time we talked - a couple of weeks ago - I think I was able to strongly rebut all of his points except one. This last involved the blister beetle, an insect in the Mojave Desert. As larvae, blister beetles parasitize larval bees; one particular species, meloe franciscanus, has an unusual way of finding them. A group of beetles climb a stalk of grass, arrange themselves into a bee-shaped ball, and emit bee pheromones. If they are lucky, a male bee finds them and tries to mate with them before they die up there. A few beetles are able to jump onto the male bee. Then the male bee mates with a female bee, and the beetles jump onto her. Then the female bee carries the beetles back to her nest, and the beetles finally get some bee larvae to parasitize.

My uncle's question, in the tradition of irreducible complexity, is: how would this kind of behavior evolve? I mean, he understands that kin selection means some of the larva will be okay with dying if it helps the others reach food, but how did the whole process even begin? Going up on a stalk of grass and forming a bee-shaped ball is complicated behavior, it's totally useless unless you can get a bee to come mate with you which seems to require the pheromones, that's useless unless you can transfer to a female bee, and that's useless unless you can transfer to her nest. How do you go from being a normal beetle going around eating dung and doing normal beetle things to this series of behaviors?

I gave the best answer I could, which was something like "People are notoriously bad at imagining these sorts of things, and there have been many previous examples of so-called 'irreducible complexity' which turned out to be reducible after all once people investigated further. Although I can't personally think of how this might have happened the argument from personal incredulity is a pretty weak reason to throw out something as well-supported as Darwinism". Needless to say this satisfied neither him nor myself.

My normal strategy here - going to http://www.talkorigins.org/ has failed me for the first time. And although the site "Why Evolution Is True" has some really neat pictures and videos of the beetles, it disappointingly refuses to give its namesake explanation in this particular case.

Anyone want to help a brother out?

[User Picture]From: maniakes
2012-08-15 04:22 am (UTC)
It looks like the general pattern of the broader Meloidae family of blister beetles is for their larva to feed on other insect larva, mainly bees. Strategies vary among different species in the family: some lay eggs near bee colonies and have larva that seek out bee (or other insect) larva, some lay eggs wherever and eat whatever's handy, and some go through varying degrees of trickery to actively attract the target species and hitch a ride.

The Meloe genus is mostly specialized on bee larva, and particularly on hitching a ride on adult bees to the bee larva. These three species in particular all appear to hang out near flowers, then hitch a ride on a solitary bee back to its nest, where it attacks the larva.

I imagine the evolutionary path looks something like:

0. Generalist ancestral blister beetle lays eggs near bee nests, and its larva try to crawl in and attack the larva.

1. Over many generations, the generations of beetles evolve to hang out near flowers and attack worker or solitary bees rather than going looking for bee nests, as with the other species currently in the Meloe genus.

2. Some unlucky larva will get picked up by male bees instead of females, but some have mutations that lets them transfer from male to female bees. The larva with that mutation are more likely (twice as likely?) to survive and reproduce, so the mutation spreads.

3. Mutations arise that make some of the beetles emit pheremones that attract male bees, increasing the likelihood of bees vising their flowers in particular. Since they already know how to transfer from male bees to females, and from females to larva, this is a big evolutionary advantage.

4. This works so well as a survival strategy that they don't even need to look for flowers anymore, just hang out at the tops of any old stalk and smell like sexy bees.

5. The more they *look* like bees in addition to smelling like bees, the more likely they are to attract bees and survive to reproduce. So mutations that make them start hanging out together in a vaguely bee-like lump are advantaged. Then more mutations accumulate, doing a better and better bee impression over the generations.
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[User Picture]From: andrewducker
2012-08-15 06:42 am (UTC)
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[User Picture]From: maniakes
2012-08-15 06:51 am (UTC)
Here's a good article on the general habits of the blister beetle family:
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[User Picture]From: squid314
2012-08-17 06:40 am (UTC)
Thanks. I may send this to my uncle. I'll let you know what he thinks.
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[User Picture]From: handleym99
2017-01-13 08:16 pm (UTC)
Yeah, I think this gets at the general point that
- the ordering of events in ONE beetle's life
does not have to match
- the ordering of the evolution of behaviors
And in fact there's absolutely no correlation between the two.

This is kinda obvious when pointed out, but is not the way the human mind usually thinks. So people always try to create a story based on
- why would the beetles evolve to build a ball?
Once that's done
- then why would they evolve to emit pheromones
Then ...

E O Wilson has a similar argument (in structure, not details) for the evolution of sociability in various species ( _The Social Conquest of Earth_ ) and once again (IMHO) the important take-away is that the order in which things evolve is utterly decoupled from the order of events in any individual animal's life.
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[User Picture]From: dudley_doright
2012-08-15 04:30 am (UTC)
I assume there just used to be a *really crappy* version of this strategy. Something like climb a blade of grass (or a flower?) and maybe hitch a ride on a bee and chow on some bee larvae. And then maybe make some bee pheromones, and then maybe start thinking about bee-shaped balls.
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[User Picture]From: pktechgirl
2012-08-15 05:40 am (UTC)
The pheromone thing doesn't seem that hard: it probably helps you just walk into a hive too. So if maniakes's research is correct, that could have come from an ancestral beetle with the easy to evolve strategy of "walk towards all that food"

I'm unconvinced the bee shape is important. I've seen male bees attempt to mate with rocks thrown across the resource patch they were guarding. This could definitely have evolved after the rest of the system was in place.

The bee riding behavior seems the hardest to evolve. You can picture that happening gradually by hanging out in front of the hive, then jumping on to a bee to get past the guards. Alternately, the family Meloidae seems to have a few flower eaters in it. Maybe an omnivorous beetle hitched a ride accidentally?

Transferring from male bee to female bee doesn't seem that hard to me. The females probably smell more like food anyway.
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[User Picture]From: cartesiandaemon
2012-08-15 10:39 am (UTC)
You know this better than me, but remember you won't be able to explain EVERY POSSIBLE mystery in evolution. To me, the question seems to be more: if every mystery we discover gets figured out 15 yrs later, is this MORE mysterious than ones we already figured out? If so, maybe it's an exception. If not, I'm not sure why this one is going to be the exception.
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[User Picture]From: hentaikid
2012-08-15 02:42 pm (UTC)
Yeah, coevolution arms race explains the complexity of the behaviour, remember the bees are trying to evolve anti parasite defenses too, so the beetles have to up their game gradually too. Like the slave ants that stage rebellions in the slaver's nests... or the birds that kick out the cuckoo chicks when they recognize them.
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[User Picture]From: Louis Burke
2012-08-15 09:49 pm (UTC)

The brain.

Have you given any thought to how the brain evolved which seems far more complex and why I doesn't annoy you? It doesn't seem like complex systems are a problem for natural selection given enough time and organism turnover and judging by the larvae there's a lot of turnover.
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[User Picture]From: mercureal
2012-08-17 09:25 pm (UTC)
I am intentionally skipping all the comments on this page because what I love most in this world is the study of evolution and insects, and I'm not going to try to explain any of countless ways such behaviors evolve (name any organism and it's got a parasite; name any parasite and there's a good chance IT'S got a corresponding hyperparasite), but I'd like to share that I worked for two years in a lab with an entomologist/biochemist who is studying these blister beetles for her PhD. She's been studying them for more than a decade. Also, she worked with David Attenborough to film her research subjects! Hello daydreamed pinnacle of my career.

Her name is Leslie Saul (or Saul-Gershenz, author of the paper Why Evolution Is True references). Her website is http://www.lsaul.com/research.htm, and if you can't find what you're looking for in (or are paywalled out of) her papers, I'm sure she'd be open to an email expressing interest in her research, especially from somebody outside the field.

I don't suppose you want to fuel your uncle's fire, and I don't really want such a book to be out there, but bro should look into fungal life cycles - Mr. Bloomenfield's Orchard is a fun informative book (by author Nicholas P. Money). No expert in the world can explain the evolutionary origin of the majority of fungal reproductive behavior. By comparison, the beetle/bee relationship is hardly hopelessly/"irreducibly" complex.

P.S. One of my favorite figures is that there are far more species of dung beetle on this planet than species of mammal.
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[User Picture]From: squid314
2012-08-18 03:45 pm (UTC)
The problem with Ms. Saul is that during our previous discussion my uncle said something like "I even emailed the world expert on blister beetles with my theory, but she refused to answer my questions". Since there can't be too many experts on blister beetles (and I do think he said "she" rather than "he"), I have a feeling he already emailed her and alienated her by starting off with an anti-Darwin tirade or something, so I would hate to bother her further.

The dung beetle stat is pretty cool, though.
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[User Picture]From: reddragdiva
2012-08-20 12:12 pm (UTC)
Jerry Coyne does interact with the readers, if you ask the actual question on WEIT then someone is reasonably likely to give some sort of helpful answer. (The biology posts don't get nearly as much action as the atheism posts, but if your question is an early comment it should.) Or you could even email Dr Coyne and ask the question as a suggested post topic - he's right into the idea that a scientist owes the public explanation and education.
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[User Picture]From: reddragdiva
2012-08-20 12:13 pm (UTC)
Oh, and if you point out the reason is to combat pseudoscience, I predict that will catch his attention!
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From: Kevin Pedro
2012-09-11 08:18 pm (UTC)
I do not have a specific explanation to offer for this case, biology not being my field. However, if your uncle is stuck on "irreducible complexity" as a general principle, it might be worth directing him to the reducibly complex mousetrap (http://udel.edu/~mcdonald/mousetrap.html).
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[User Picture]From: Adam Isom
2013-01-24 03:06 am (UTC)
Is it really so bad to say "for any theory which explains thousands of previously unexplained or ill-explained facts, there are bound to be a few facts in the same domain which we can't currently explain, because that's just how human ignorance is?"

Either there is an implicit standard of airtight 100% proof that we need to give up in this post-Scholastic-era world, or we need to find some way to convince people that when they focus in on the beetle (and out on everything else, the millions of data points evolution does or could explain) they're going to have a bad time, truth-seeking wise.
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