"Women definitely like heated seats."

Savage Car Talk mashes up the Magliozzi Brothers' Public Radio automotive advice show with questions submitted to Dan Savage's no-holds-barred sex and relationship advice podcast. The result is not suitable for work, unless you work in an automotive-themed gay bar.

This makes total sense. Dan takes a pretty left-brained, mechanistic approach to the relationship problems brought before him. Click and Clack talk about relationships almost as much as they discuss cars. Many times, I've run across relationship and automotive problems of my own that seemed like they would be worthy of a phone call to the appropriate show—only to realize I already knew the answer thanks to long hours of listening to advice given to other people.

Also, I've heard that almost a third of Dan's misanthropic snark is added in post-production.

Via Dan Savage. I'm still waiting to hear what the Car Talk guys think.

You're a sad man, Charlie Brown

Via HiLoBrow: 3eanuts removes the fourth panel from "Peanuts" cartoons, and with those fourth panels goes the leavening of humor from Charles M. Schulz's bleak world. As the AV Club points out, this doesn't necessarily make "Peanuts" any more depressing than it already was.

Moths that pass in the night: Reproductive isolation due to pickiness, or just bad timing?

On a summer night in a Florida corn field, a female armyworm moth emerges from her underground cocoon and spreads her wings to dry in the humid air. Over the next few weeks, she will fly miles away in search of a mate, and a likely-looking patch of host plants on which to lay her eggs.

Her brief adult life will be shaped in many ways by the life she led as a larva, feeding on domestic corn. She could easily find other grasses to feed her offspring, but she'll probably seek out another cornfield. She may encounter armyworm males who were raised on many other grasses, but the odds are that the males she accepts as mates will also have grown up eating corn. This is so likely to be the case that it has left a mark on the genetics of her species [PDF].

At night in a cornfield, moths mate nonrandomly. Photo by K e v i n.

Yet it isn't clear how much of this isolation between armyworms from corn (the "corn strain") and armyworms from other grasses (called the "rice strain") arises because moths from the different host plants actively prefer mates from their own larval food plant, or because they just don't encounter moths from the other food plants as frequently. Like many moths, armyworms of both sexes deploy pheromones to attract and woo mates—so maybe armyworms from the same food plant smell better to each other. On the other hand, corn-strain armyworms do more of their mate searching early in the evening (although they'll keep hunting all night), while rice-strain armyworms wait to search till the last few hours of nighttime.

Disentangling which of these two sources of isolation—preference versus timing—maintains the genetic differences between host plant strains of the armyworm takes some careful experimental work. As in many biological questions, the answer might well be not one or the other, but a little of both [$a].

In which I try to explain why "heritability" is not quite the same thing as "heritable"

Robert Kurzban responds in the ongoing "adaptive" homophobia kerfuffle (henceforth, the O.A.H.K.) with continued confusion about how biologists identify possible adaptations and test to see whether natural selection is responsible for them. He notes that one effect of natural selection is to remove heritable variation in traits under selection, so that many traits which are probably adaptations—arguably, sometimes the best-adapted traits—actually have zero heritability.

This is true. But it's important to note that a trait having zero heritability, or no genetic variation, is not the same thing as that trait not being heritable, or having no genetic basis. If the trait has zero heritability, the observed variation in the trait may not be heritable, but the trait still may be. Kurzban's confusion over this distinction may be a fault of the terminology, as was pointed out to me in a couple independent conversations following the last round of the O.A.H.K.

That aside, reduced heritable variation in a trait—relative to appropriate standards for comparison, like other traits in the same species or the same trait in closely related species—is sometimes used to infer that selection has acted on that trait in the past. This is what my lab has done in the case of Joshua tree and its pollinators, which Kurzban cites. This sort of approach provides only indirect evidence of natural selection's activity—but it's often the best you can do when your focal species isn't amenable to growing in a lab or greenhouse within the span of a single grant cycle.

The two varieties of Joshua tree, because apparently these are part of the discussion now. Photo by jby.

The comparison to other traits or to other species is the critical point here. Without it, you can't determine whether a lack of genetic variation is due to strong selection, or due to the fact that there is no genetic basis for the trait. In isolation, the observation that there is no heritable variation for a single trait or behavior in a single species doesn't tell you much except that natural selection cannot currently be acting on the observed range of variation in that trait. If there's no genetic basis for the trait at all, then it cannot have been under selection in the past, either.

Forming hypotheses versus testing them

Regarding Kurzban's broader point about how biologists identify adaptations:

Science online, "I tawt I taw a puddy tat" edition

Rawr! Photo by pasma.

Wink wink, nudge nudge, Facebook. Say no more.

• You can't cuddle a wind turbine. Everybody's worried about the birds killed by wind turbines, but domestic cats kill more than 1,000 times more.
• Evolved in response to complaints from the downstairs neighbors. Giant (well, 26-pound) rabbits that lived on Minorca three to five millions years ago probably didn't hop.
• File under: more evidence in support of common sense. Regular testing for HIV doesn't just help prevent transmission—it can also improve health outcomes if infection does occur.
• Best opening anecdote ever? Those penis spines we heard so much about recently might not have the function folks think they do.
• Speak up! When windy conditions make social signalling by head-bobbing less obvious, anoles modify their communication method.
• Ironically, Stephen Jay Gould changed his mind gradually. When, if ever, do prominent biologists admit they're wrong?
• Hint: read the comments on this one. Months after the "arsenic life" paper was roundly criticized in online fora, its authors respond in print.
• In case you missed it. Jesse Bering and Gordon Gallup respond to criticism, and do not improve their case. P.Z. concurred, and hectocotyli found still other faults.

In which several evolutionary psychologists still don't understand evolution

Jesse Bering has responded to criticism—by me, Jon Wilkins, and P.Z. Myers, among others—of his post about Gordon Gallup's hypothesis that fear of homosexuals is favored by natural selection, in the form of an interview with Gallup. The result is informative, but probably not in the way intended.

To recap: Gallup proposed that homophobia could be adaptive if it prevented gay and lesbian adults from contacting a homophobic parent's children and—either through actual sexual abuse or some nebulous "influence," making those children homosexual. In support of this, he published some survey results [$a] showing that straight people were uncomfortable with adult homosexuals having contact with children.

I pointed out that all Gallup did was document the existence of a common stereotype about homosexuals—he presents no evidence that believing this stereotype can actually increase fitness via the mechanism he proposes, or that it is heritable.

Homophobia. And, um, everyone-else-phobia, too. Photo by yksin.

So now Gallup and Bering have responded, although they have not, I think, improved their case. There's a lot for me to address here, so I'll try to break it up into sections, and follow the order of the interview.

In which Gordon Gallup is not a homophobe

In the response post, Gallup (and Bering, who contributes quite a lot to the argument in his role as interviewer) takes issue with the collective objections of working biologists, but manages not to actually address those objections. Bering starts the conversation on the moral high ground:

BERING: Let’s address the elephant in the room. It’s embarrassing for me to even ask this of you, since the answer is so obviously "no" to me. Is your theory a justification of your own homophobia?

GALLUP: A lot of people think that if a person has a theory it’s a window unto their soul. I have lots of theories. (See CV (pdf).) I have a theory of homophobia, I have a theory of homosexuality, and I have a theory of permanent breast enlargement in women, just to mention a few. So that would make me a homophobic, homosexual who is preoccupied with women’s breasts.

Neither I, nor any of the other critics I've seen have called Gallup a homophobe. He may be uniquely bad at understanding how societal homophobia nullifies his interpretation of his survey results, but that doesn't make him a homophobe. Thanks for clearing that up, though, guys.

Gallup then demonstrates that he either hasn't actually read any of the latest criticism, or has missed the point entirely:

Parasitism of a different color

The common cuckoo is such a lazy parent that brood parasitism—laying its eggs in the nests of other birds—is built into its biology.

No bird will willingly adopt cuckoo chicks, which usually out-compete, and sometimes kill, their adoptive siblings. Given any hint that one of the eggs in her nest isn't hers, a bird will eject the intruder. So cuckoos have evolved eggs that mimic the coloring of their hosts' eggs—dividing the species into "host races" that specialize on a single host species, and lay eggs that mimic that host's.

Cuckoo eggs (indicated by arrows) in the nests of three different host species. Illustration via The Knowledge Project.

As you can see from this illustration, the match is often extremely good—the cuckoo egg is really only obvious when the hosts' eggs are visibly smaller. In fact, a new study by Mary Caswell Stoddard and Martin Stevens shows that this matching is often even better than it looks to the human eye [$a].

Open Lab 2010 available for purchase!

The Open Lab 2010 is here!.

Bora Zivkovic has just announced that the Open Lab 2010, the latest edition of the annual collection of online science writing, is now available for print on demand. Congrats to the hard-working team who put it all together: Bora, Jason Goldman, Andrea Kuszewski, and Blake Stacey.

OL2010 features my first-ever contribution to the collection, the tale of J.B.S. Haldane's role in Soviet scientific propaganda, as well as top-notch work by Eric Michael Johnson, Carl Zimmer, Deborah Blum, Steve Silberman, Kate Clancey, and many others. So what are you waiting for? Go buy a copy or three.

Science online, spring break edition

The weather was lousy, but the coffee was excellent. Photo by andrewyang.

I spent most of my final spring break as a graduate student in Portland, Oregon, where I am not sure I saw direct sunlight even once. Who wants to get a tan over spring break, anyway? Regular posting resumes when I'm back in Moscow next week. If you "like" D&T on Facebook, you'll get an alert about that right in your News Feed (TM). That's a good thing, right?

• Not sure this'll be practical in Portland. Solar power systems became both cheaper and more efficient in the last twenty years, and they're likely to keep doing so.
• Not helping. If you're HIV positive in Missouri, you can be prosecuted for "recklessly" transmitting HIV when you do things that don't actually transmit HIV.
• Get out your "jump to conclusions" mats. Antidepressants seem to cause increased weight gain in lab rats—but that doesn't mean they've caused the obesity epidemic.
• Take two mind games and call me in the morning. Even if you tell a patient the truth, prescribing a placebo can be ethically complicated.
• Sperm aren't that tough to kill. A contraceptive pill for men is probably about five years away. In fact, it's been about five years away for decades.
• Blood and rhetoric. The first attempts at blood transfusion were greeted with controversy that prefigured our modern debates over stem cells and genetic engineering.
• No blarney. Krystal D'Costa recounts how the Irish first came to the Caribbean as slaves.
• In case you missed it. Jon Wilkins bounces off the "adaptive homophobia" kerfuffle to explain more broadly why plausibility is not enough to test adaptive hypotheses. In related news, I got Phrayngulated.

The evolution of homophobia, continued

On Twitter, hectocotyli just pointed me to another discussion of the problems with Gordon Gallup's case for an adaptive function to homophobia (and linked to my take in connection, for which, thanks). Jon Wilkins goes into more detail on the general problem that evolutionary psychology too often accepts plausibility as the standard of proof for adaptive hypotheses.

In fact, it is trivially easy to come up with a plausible-sounding evolutionary argument to describe the origin of almost any trait. More importantly, it is often just as easy to come up with an equally plausible-sounding argument to describe the origin of a hypothetical scenario involving the exact opposite trait.

I think Wilkins is a little too polite in some regards; Gallup's hypothesis doesn't even qualify as "plausible" in the context of what we know today about its ugly component assumptions. (And what, by the way, Jesse Bering should have known before dredging up Gallup's articles from well-deserved obscurity.) Nevertheless, Wilkins broadens the discussion to address scientific reasoning more generally, and the post is worth reading in its entirety.

Science online, mnemonic rats edition

Bat in flight. Photo by tarotastic.

Blah blah blah, Facebook, blah blah blah.

• When life gives you parasites ... Ancient ammonoids—forerunners of modern squid and nautiluses, dealt with parasites by encasing them in pearl.
• Evolutionary baby pictures. Bats' evolution from flightless ancestors, illustrated.
• Note to my students: no human testing planned yet. Enhancing the levels of a particular enzyme in rats' brains helps them retain memories.
• Discredited more than a century ago, but you get to use a "cephalometer of Anthelme." Want to make a living reading people's personalities by the bumps on their head? Maybe phrenology is for you.
• Using foremost legs as antennae, even. Spider mimics ant surprisingly well.
• Sensory metaphor hijinks. People are more likely to identify an ambiguously-gendered face as female when touching something soft.
• Glass ceilings are durable. Active discrimination may not be preventing women from advancing in the sciences, but institutional biases sure are.
• Don't panic. Panic Virus author Seth Mnookin understands the parental worries underlying vaccine denialism, but he still thinks it's a problem.
• In case you missed it. Jesse Bering thinks homophobia might be adaptive. He's wrong.

And now, after a string of weeks without video in my Friday roundup, I give you a slow loris with a tiny umbrella.

An adaptive fairytale with no happy ending

The evolution of human traits and behaviors is, as I've noted before, a contentious and personal subject. This is enough of a problem when there's some data to inform the contentiousness. In the absence of meaningful data, it's downright dangerous.

Take, for instance, Jesse Bering's recent post about the evolution of homophobia, which Steve Silberman just pointed out to me.

A grim fairy tale indeed. Photo by K Wudrich.

When evolutionary biologists say a trait or behavior is "adaptive," we mean that the trait or behavior is the way we see it now because natural selection has made it that way. That is, the trait or behavior is heritable, or passed down from parent to child more-or-less intact; and having it confers fitness benefits, or some probability of producing more offspring than folks who lack the trait. Lots of people, including some evolutionary biologists, speculate about the adaptive value of all sorts of traits—but in the absence of solid evidence for heritability or fitness benefits, such speculation tends to get derided as "adaptive storytelling."

Evolutionary biology wasn't always so rigorous, once upon a time. Then Stephen Jay Gould and Richard Lewontin buried adaptive storytelling under an avalanche of purple prose in their landmark 1979 essay "The Spandrels of San Marco" [PDF]. Norman Ellstrand made a similar point with better humor in a satirical 1983 article for the journal Evolution proposing adaptive explanations for why children always start life smaller than their parents [PDF]. Nowadays, when evolutionary biologists want to, say, argue that horned lizards' horns are an adaptation for defense against predators, they have to demonstrate the claimed fitness benefit [PDF].

Evolutionary psychologists, however, seem not to have gotten the memo.

One snout to rule them all: Does migrating help weevils win the arms race of coevolution?

Natural selection and gene flow have a sort of love-hate relationship. Natural selection acts, on average, to make a population better fit to its environment. Gene flow, the movement of individuals and their genes, can counter the optimizing effect of selection if it introduces less-fit individuals from somewhere a different environment. On the other hand, not all new immigrants are necessarily less fit—sometimes they're better suited to their new environment than the locals.

This gets more complicated, and more interesting, when the environment in question is another living species. Then, the question is not just how movement of one species changes its response to natural selection, but how movement of the other species changes the nature of that natural selection. That's the focus of the latest study of a Japanese weevil species and its favorite food plant. The two species are locked in a coevolutionary arms race—but who wins the arms race in any given location depends on the gene flow each species is receiving from elsewhere [$a].

Male and female camelia weevils, caught at an indelicate moment. Evidently he doesn't find her much longer rostrum intimidating. Photo from Toju et al. (2011), figure 1.

These are camelia weevils, Curculio camelliae. As their name suggests, they like to eat camelias, at least when they're young. Specifically, weevil larvae eat camelia seeds, which are protected by a thick layer called a pericarp. To deal with camelia pericarps, the weevils have evolved prodigious proboscises, or rostrums, which female weevils use to drill through the pericarp so they can lay their eggs inside. Note that the female in the picture above is the one with the rostrum longer than the rest of her body.

Science online, falling coconuts edition

Waiting for the next one to drop? Photo by KhayaL.

What? You still haven't told Facebook you like Denim and Tweed? But then how else will it know to send you ads for, um, obligate pollination mutualism?

• Gotta start somewhere. The simplest possible biological eye—and the starting point for the evolution of more complex models—may have been found in brachiopod larvae.
• Look out below! In Palmyra Atoll National Wildlife Refuge, introduced coconut palms are literally bombing the natives into extinction.
• In case you missed it. The Carnival of Evolution is out at Genome Engineering.
• Herpetologist porn. Anolis osa has just been differentiated from Anolis polylepis based on what a leading Anole scholar calls their "man parts."
• Big cats, but no longer the top dogs. With population declines of more than 90 percent since 1960, lions are in danger of extinction in the wild.
• But wait, there's more. It's not looking so great for every other known species, either.

Testimony from the front lines, Exhibit B.

Via the Hairpin's sister site The Awl this time: Queer students at the very Christian Harding University have published a 'zine trying to explain themselves to the rest of the student body. It's pretty damn' hard to read, although maybe just because it sounds pretty damn' familiar to me:

Our voices are muted, our stories go unheard, and we are forced into hiding. We are threatened with re-orientation therapy, social isolation, and expulsion. We are told stories and lies that we are disgusting sinnners who are dammed [sic] to hell, that we are broken individuals and child abusers. We are told we will live miserable lives and are responsible for the collapse of civilization. .... We are good people who are finished being treated as second-class citizens at Harding. We have done nothing wrong and we did not choose this suppression.

From the vantage point of someone for whom it got better, it's hard not to see a certain amount of cognitive dissonance underlying the attempts to engage the intended audience with Biblical exegesis. But you know what, Harding University queers? Whether or not God hears your "cries for liberation from harsh oppression," the rest of us do.

Naturally, Harding University has blocked access to the 'zine website on its campus.

Testimony from the front lines, Exhibit A.

Over at The Hairpin, which is rapidly becoming one of my favorite blogs, Dolores P. explains why she is training to become an abortion provider. And, wow. It's incredible from start to finish, but her accounts of specific patients' stories will blow you away:

Couple days later one of our patients was a soldier from Afghanistan. Hey, I was just reading about you guys.

No contraception around (she was stationed pretty far out) meant that she got pregnant. "Regulations require that a woman be flown home within two weeks of the time she finds out she’s pregnant, a particular stigma for unmarried women that ends any future career advancement." Ends any future career advancement. For my patient, that meant that she had to figure out how to make it back to the states on her own. Even if she had chosen to “go straight,” it wouldn’tve been much better: “Servicewomen who make the decision to have an abortion must first seek approval from their commanding officer to take leave from their military duty and return to the United States or a country where abortion is legal.” (Guttmacher.) Ask your boss if you can please take off a while for your abortion. And no matter what, she had to pay for it all herself. So even though she knew she was pregnant almost immediately, it took eight weeks to make arrangements, travel plans and raise all the money. That means by the time she walked in our door, she was beginning her second trimester, which is a way more expensive and invasive procedure. She also had to spend eight more weeks than she had to miserably pregnant. In Afghanistan. [Hyperlink sic.]

Meanwhile, the House of Representatives is trying to eliminate Federal funding for Planned Parenthood, 100 percent of which goes towards services that help avoid abortions. You should go do something about that right now.

Carnival of Evolution No. 32

Barnacles, one of Darwin's first study organisms. Photo by Minette Layne.

The 32nd Carnival of Evolution, collecting online writing about exactly what it says on the tin, went live yesterday at Genome Engineering, with contributions from yours truly, Zen Faulkes, Bite Sized Biology, Dr. Bik, and Kevin Zelnio. Go have a look!

xkcd discovers phylogenetics

Of course, no real ornithologist would propose this, because biology faculties everywhere would take it to mean that at least one zoologist was redundant, phylogenetically speaking. Click through to the original for the hovertext.

Pollinating birds leave plants in the lurch

Plants' ancient relationship with animal pollinators is pretty crazy, when you think about it. On the one hand, it gives plants access to mates they can't go find on their own, and it's more efficient than making scads of pollen and hoping the wind blows some onto another member of your species. On the other hand, it can leave a plant totally dependent upon another species for its reproduction.

This catch is probably why lots of plants still use wind pollination strategies, or reserve the option to pollinate themselves if animals don't do the job for them. Avoiding complete dependence on animal pollinators is likely to become more important in the modern era, as human disruption of the environment amplifies the inherent risk of entrusting your reproduction to another species [$a], a study in the latest issue of Science shows.

A flower of Rhabdothamnus solandri, waiting for pollinators who may never show up. Photo by Tonyfoster.

Sandra Anderson and her coauthors examined the health of populations of Rhabdothamnus solandri, a forest shrub native to the North Island of New Zealand. The flowers of R. solandri are classic examples of the pollination syndrome associated with birds—bright red-orange, with long nectar tubes. Rhabdothamnus solandri is incapable of self-pollinating, because its The flowers attract three native bird species, the tui, the bellbird, and the stitchbird. Thanks to human activity, all three of these birds "functionally extinct" in most of the range where R. solandri grows.