When it comes to keeping secrets, the U.S. Air Force knows how to stay mum. On Thursday, the Air Force will launch its secret space plane, the unmanned X-37B aircraft, from Cape Canaveral. The project has been a decade in the works and cost millions of dollars to develop–but we civilians have little idea what it’s for.

Once launched via an Atlas V rocket, the plane is expected to spend days or weeks orbiting Earth and performing classified experiments before landing back in California. If successful, the launch will fulfill the Defense Department’s long-time dream: the orbital flight of a military vehicle that combines an airplane’s agility with a spacecraft’s capacity to travel in orbit at 5 miles per second [Popular Mechanics].

The project itself has had an interesting past. It was begun by NASA in 1999 but was later adopted by the Defense Department, and was first placed under the auspices of DARPA before finally finding a home with the Air Force. The Air Force immediately threw the X-37B behind a veil of secrecy, leading some experts to speculate that this could be the military’s attempt to weaponize the final frontier. There are also concerns that the mysterious project could set off an orbital arms race with countries like China.

The 29-foot-long delta-wing spacecraft looks like a miniature version of a space shuttle. The unmanned X-37B is capable of cruising around the globe for more than nine months at a stretch, experts say, keeping close tabs on targets below and monitoring the space above. Its small size and simplicity are great assets to the military, because they’ll allow for the aircraft’s quick deployment in emergencies. Theresa Hitchens, a space policy expert and director of the United Nations Institute for Disarmament Research says the X-37B might be intended to be an orbital first responder. “The first thing that comes to mind is a pop-up reconnaissance vehicle for a place where you don’t have satellite reconnaissance or can’t move a satellite fast enough” [Popular Mechanics], she says.

Though the air force has been mum about the space plane’s potential uses, experts speculate it could conceivably be used as a bomber. The craft could fly over targets within an hour of launch to release cone-shaped re-entry vehicles that would both protect and guide weapons through the atmosphere. A craft the size of the X-37B could carry 1000- or 2000-pound re-entry vehicles armed with precision munitions like bunker-busting penetrators or small-diameter bombs, or simply use the explosive impact of kinetic rods cratering at hypersonic speeds to destroy targets. [Popular Mechanics].

When the first X-37B returns to Earth, scientists will determine how many of its components survived the flight and how long it will take to get the craft back into the air. The shorter the turnaround time, the better, since that would mean fewer X-37s would have to be built, regardless of its ultimate mission [The Christian Science Monitor]. For now, the Air Force is simply preparing for tomorrow’s launch and refusing to spill the beans on the space plane’s potential uses. But the military seems optimistic about this long-delayed program; Air Force officials have admitted that they have a second X-37B in the works, which they hope to take out for a test flight by 2011.

Related Content:
80beats: Highway to the Green Zone? Navy to Test a Supersonic Biofuel Jet
80beats: Will the Pentagon Build the Jetsons’ Flying Car?
80beats: Meet the “Puffin,” NASA’s One-Man Electric Plane
80beats: DARPA Wants a Biofuel Jet, While Germany Works on a Hydrogen Plane

Image: U.S. Air Force

My pal Darlene Cavalier from Science Cheerleader twigged me on to a project she’s helped develop: Science for Citizens, a collection of websites for projects where citizens — that’s you! — can help do science. There are a lot of interesting projects there, from using Hubble to bird watching.

There are a lot of familiar ones there — Stardust@Home, for example — as well as educational projects for kids and older students. It’s a treasure trove of ideas! I’m a big fan of citizen science, in fact. Amateur astronomy has and probably always will be an important aspect of astronomy, since there is a vast amount of excellent science that can be done with smaller, personal observatories. Lots of other fields of science are figuring this out as well, so you should take a look and see if anything there captures your interest. There’s something there for pretty much everyone.

Attention, people of Yale, New Haven, and environs! I will be giving a talk Friday called “Science and the Media: A Match Made in Heaven, or a Cosmic Train Wreck?”

I’ll offer my bipolar musings on the once and future state of science journalism. It’s free and open to the public

It’s sponsored by the Yale Training Program in Biophysics, the Department of Molecular Biology and Biophysics, and the Poynter Fellowship in Journalism at Yale.

Here are the details:

When: Friday, April 23, 2010 4:00 PM
Where: Bass Center for Molecular and Structural Biology (BASS), Rm. 305
266 Whitney Ave., New Haven, CT 06511

More information here. and here.

Low Vitamin D Levels Associated With More Asthma Symptoms and Medication Use. Not a randomized double blind study. Rather, they look at the correlation, and they did some cell biology experiments. Looks like high levels of vitamin D enhances the action of corticosteroids.

Recreational genome sequencing for the whole family. I’m kind of irritated as the “ethical concerns” about this information. Information may not always want to be free, but this is pretty much an inevitability. Since there’s no plausible way you can cordon it off you need to educate people to use the information wisely. Unfortunately most of the populace is not too intelligent, but that just means you need to work hard in making the heuristics simple and obvious.

Genetic Basis for Health Benefits of the ‘Mediterranean Diet’. Turns out it might be a matter of gene expression.

Thinking About Tomorrow. Delaying gratification is really important, and often hard.

Why Texas is doing so much better economically than the rest of the nation. Daniel Gross focuses on the fact that Texas is globalizing and export-oriented. I note that only Utah has a lower median age. I suspect that the young work force in its peak years makes it easy for Texas to have a low public service state and focus on private sector wealth generation.

John Hawks has a post up, Multiregional evolution lives!, in response to Rex Dalton’s reporting on Neandertal-human admixture. He notes:

These ongoing studies are concluding that present-day genetic variation is inconsistent with a simple model where a random-mating ancestral population gives rise to today’s global population by means of a staged out-of-Africa dispersal. They next look at a model with some substantial (possibly complete) isolation between ancient human populations followed by a subsequent out-of-Africa dispersal. They show that this model fits the data significantly better.
So far, so good.

For a moment, I’m going to adopt a critical perspective. Previous results haven’t yet been able to answer an important possible question: Can they distinguish the effects of intermixture outside Africa from an ancient population structure inside Africa? Increasingly it looks like population structure inside Africa may have been very important to the evolution of Late Pleistocene Africans. How can we distinguish these kinds of structure from each other?

The short answer is that maybe we can’t, yet. Human population history was not simple. If we take a simple model and add more parameters, it will fit the data better. The question is whether there may be some even better model with the same number of parameters. Population structure within Africa, selection on some loci but not others, asymmetrical migration — all these and more might be possible.

The Out of Africa + total replacement model had a clean elegance, but it might not be viable in the near future. That being said it seems to me that the old Multiregional model implied, though proponents were often careful to reject this characterization, more regional parity than was the case. I do not expect the predominant African ancestry of modern humans to be rejected for example. There are other frameworks out there, such as Alan Templeton’s Out of Africa again and again (Richard Dawkins favors this in The Ancestor’s Tale).

Muslim Group Says It Is Warning, Not Threatening, ‘South Park’ Creators. Here’s a screen shot from the cached version of the site (it was hacked after the threat):

The website is run by a dozen crazy people. No word on crazy Buddhists objecting to the fact that Buddha was depicted as a cocaine snorting junkie in the episode. It’s a two part episode, so watch the finale tonight.

In my lastest podcast, I talk to Keith Klugman of Emory University about pneumonia–how its devastation worldwide is worse than we once thought, and how vaccines are proving surprisingly effective at keeping it in check. A pneumonia vaccine may even prevent a replay of the 50 million deaths during the 1918 Spanish flu pandemic. Check it out.

In today’s edition of far-out science, researchers have found evidence that the wafting aroma of food has an effect on an organism’s lifespan–and they’ve demonstrated that interfering with a fruit fly’s sense of smell causes it to live a longer, healthier life. While there’s no guarantee that the trick would work for humans, optimistic researchers suggest that certain odors—or drugs that block us from sensing them—might one day help prevent disease and extend lives [ScienceNOW].

In the past decade, scientists have established a clear connection between extremely low-calorie diets and extended lifespans; studies have demonstrated that yeast, fruit flies, mice, and monkeys on these diets live longer than their peers. While the exact mechanism at work isn’t yet clear, researchers suspect that a near-starvation diet causes an organism’s metabolism to slow down, and triggers other changes that evolved to help organisms survive in times when food was scarce. Now scientists say it may not be just what a creature eats, but also what it smells that has an effect on how long it lives.

In one 2007 study, molecular biologist Scott Pletcher and his colleagues found that completely eliminating fruit flies’ sense of smell caused them to live nearly 20 percent longer than normal flies. They also found that wafting the smell of yeast, a tasty treat for fruit flies, towards flies that were on a low-cal, live-extending diet hastened the death of those flies. This led the scientist to hypothesize that specific odors might be influencing the flies’ lifespans. Luckily, other scientists had identified a receptor in a group of neurons that enable fruit flies to smell carbon dioxide, which signals the presence of a good meal of tasty yeast [ScienceNOW]. So, Pletcher and his team set out to find if the CO2 had anything to do with the duration of the flies’ lives.

For the new study published in PloS Biology, Pletcher eliminated the fruit flies’ ability to smell carbon dioxide, while keeping the rest of the olfactory system intact. Even on a standard, full-calorie diet, the flies that couldn’t detect CO2 lived up to 30 percent longer than other flies. The researchers suggest that the absense of CO2 may have indicated to the altered flies that food was scarce in the environment, prompting them to snap into survival mode. Oddly, however, the life-extending effect was only seen in female flies–male flies gained no such benefit. The smell-deprived female flies also seemed healthier and stronger by several measures: They stored extra fat, produced more offspring, and proved to be more resistant to oxidative stress than normal flies.

Pletcher isn’t sure how the inability to smell CO2 extended the females’ lifespans, but he says the findings open up fascinating new areas for studies of human aging. He suggests that there might be certain smells or drugs that would block certain odors, and which could give humans a bit more time before we shuffle off our mortal coils. Matt Karberlein, an aging expert who wasn’t involved in Pletcher’s research, was cautiously optimistic about that possibility, saying: “We definitely undergo physiological changes in response to smelling food – I’m getting hungry just thinking about it – so I think it’s possible” [New Scientist].

Related Content:
80beats: A Single Genetic Tweak Gives Mice Longer, Healthier Lives
80beats: Low-Calorie Diet Staves off Aging & Death in Monkeys
Not Exactly Rocket Science: Low-calorie diets improve memory in old age
DISCOVER: In Worms, a New Theory on Aging

Image: Scott Pletcher / University of Michigan, Ann Arbor

My friend Sara Mayhew is pretty cool. I am reminded of this by her interview on Skepticality this week, and I’ve been meaning to write about her again anyway.

How do I know she’s so cool? I mean, besides this being my blog which makes me the final arbiter of cool? And also that she linked to me in a fabulous cartoon she drew?

She’s cool because she’s a skeptic and she draws manga and she’s a TED fellow. And she’s also pretty frakkin’ smart. And she spreads the joy of science and skepticism through her art. Behold:

That, me droogs, is a very cool ad. And how can you not love someone who asks, "Do we have the courage to let go of our beliefs, to grab on to what is true?"

If you want more of her, then check out the talk she gave at CfI LA in March, and you too will see why I like her so much.

So I've given you the website of the Kennedy School science blogging event--cosponsored by the Knight Science Journalism Fellowships program--but not yet the speakers list. Here goes:
Program 9:30 Introduction/Framing Sheila Jasanoff, STS Program, Harvard Kennedy School 10:00-11:00 Panel 1: Blogging as Business Henry Donahue (CEO, Discover), Gideon Gill (Science Editor, Boston Globe), Representative of Seed Magazine [not confirmed] 11:15-12:15 Panel 2: Science on the Web Francesca Grifo (Union of Concerned Scientists), Chris Mooney (MIT and Discover), Jessica Palmer (Bioephemera) 1:15-2:30 Panel 3: Rules and Responsibility Amanda Gefter (New Scientist), Kimberly Isbell (Citizens Media Law Project), “Dr. Isis” (ScienceBlogs.com), Thomas Levenson (MIT) 2:30-3:30 Panel 4: Norms and Law Sam Bayard (Citizen Media Law Project), Phil Hilts (Knight Program, MIT), Cristine Russell (Harvard Kennedy School) 3:30-4:00 Open Discussion and Wrap-Up Incidentally, I also want to credit the poster artist whose work is helping so much to publicize this event: Alex Wellerstein. Amazing work.

The F/A-18 Super Hornet burns through more fuel than any other aircraft in the Unites States Navy, whose pilots have flown more than 400 of the jets. But with the week of Earth Day upon us, the Navy is trying to use the jet to show it can mend its fuel-guzzling ways. Tomorrow the “Green Hornet,” an F/A-18 running on a half-petroleum, half-biofuel blend, will make a test flight from Maryland.

Secretary of the Navy Ray Mabus has set a target that half of naval energy consumption will come from alternative sources by 2020. A “Great Green Fleet,” to sail by 2016, will include nuclear ships, as well as surface combatants with hybrid electric power systems using biofuel and biofuel-powered aircraft [National Geographic]. Before we can talk about ambitious deployment targets, however, the Navy has to prove that its “green” fighter has got what it takes, and so the experimental F/A-18 will try to break the sound barrier.

The Green Hornet’s biofuel constituent is made from Camelina sativa, also called gold-of-pleasure or false flax. (It earned the latter moniker for surviving by looking increasingly like real flax, a talent that garnered it a spot in our gallery of plant and animal impostors.) As a biofuel, Camelina has the advantage of growing with little energy input. Humans have cultivated the plant for millennia; the Romans used its oil in lamps and in cooking (pdf). Another advantage is that the fuel made from it was remarkably similar to the military petroleum jet fuel called JP-5 [National Geographic]. However, just as ordinary car engines can’t run on strictly ethanol, the design of the engine seals on the F/A-18 still demand a substantial component of conventional fuel.

Even advanced biofuels have their detractors among environmentalists and energy gurus, but the military’s potential embrace of them and other technologies—like electric vehicles, solar, and wind power—could supply the marketplace boost they need. The size of the military’s investment will create economies of scale that help bring down the costs of renewable energy, and military innovations in energy technologies could spread to civilian uses, just as the Internet did [Miami Herald].

And perhaps when you go to an air show in a decade, the Blue Angels‘ F/A-18s will be flying on biofuel.

Related Links:
80beats: London’s Garbage Will Soon Fuel Some British Airways Flights
80beats: Air New Zealand Tests Jet Fuel Made From Poisonous Jatropha Seeds
80beats: Super-Green, Algae-Derived Jet Fuel Passes Tests With Flying Colors
80beats: DARPA Wants a Biofuel Jet, While Germany Works on a Hydrogen Plane
DISCOVER: Impostors! Ten Species That Survive By Imitation (photo gallery)
DISCOVER: The Second Coming of Biofuels
DISCOVER: It’s a Bird, It’s a Plane, on flying in formation to save fuel

Image: Staff Sgt. Aaron Allmon, U.S. Air Force

We’ve all seen this scene being played out in the local park: When a guy walks a cute dog, people don’t hesitate to approach him to strike up a conversation about schnauzer breeds. Or there’s the guy-with-a-baby scenario, in which the baby-hauling dad is perceived as friendly and non-threatening (not to mention irresistible to some women).

Now, new research from France suggests that male Barbary macaques may be onto the same “baby effect” strategy. The study found that male macaques with an infant were more likely to make male monkey buddies, as the presence of a tiny, defenseless baby immediately breaks down barriers.

The study, which is due to be published in the journal Animal Behavior, is also the first to demonstrate that infants can serve as social tools for some primates, writes Discovery News.

Study coauthor Julia Fischer told Discovery News that when a male Barbary macaque comes across another male with a baby, it sets off a “bizarre ritual.”

Fischer said the males “sit together, embrace each other, then they hold up the infant and nuzzle it. Their teeth chatter and lip smack while making low frequency grumbling noises.”

The researchers found that the monkeys with babies not only attracted other males for this ritual, they also ended up with quite a few pals this way–which had benefits for these monkeys’ social status. Discovery News writes:

Males who worked their networks in such a way tended to rise up the monkey social ladder. For example, one male rose from fifth to second place after acquiring “the highest number of male partners.”

What if a social-climbing monkey doesn’t have his own kid? No problem. The study showed that monkeys sometimes borrow babies, and proceed to use the infants as friend magnets. But it’s not all fun and games for the bambino-carrying monkeys. The researchers found that, much like human males, the male monkeys got stressed out when the kids started bawling.

Related Content:
80beats: Maternal Monkey Love: Macaque Moms Coo Over Their Babies
80beats: Monkey See, Monkey Do: How to Make Monkey Friends
80beats: Do Tricky Monkeys Lie to Their Companions to Snag More Bananas?
80beats: When Baby Monkeys Throw Public Temper Tantrums, Moms Often Give In
80beats: Female Monkeys Chat More Than Males to Maintain Social Ties

Image: Andreas Ploss

It’s not just that some birds can use tools, as primates can. Their smarts stretch even further: New research this week suggests that New Caledonian crows can solve a three-step problem, in which the three steps must be completed in succession to reach a tasty snack. Alex Taylor and colleagues document this discovery in the Proceedings of the Royal Society B.

Here’s the setup: There’s a short stick dangling from the bird’s perch on a string. That short stick isn’t long enough to grab the food that’s tucked inside a long and narrow box, but there’s a longer stick in a separate box. If the birds could figure out the first two steps—grabbing the short stick, and using it to get the longer stick—then voila, they could use the longer stick to reach the food.

The team split the birds into two groups. The birds in group number one got to mess around with each step of the process individually before researchers presented them with the problem as a whole. Coauthor Russell Gray says, “All these birds had to do was to put together things they could already do in the right sequence” [BBC News]. And they did: Each solved the problem on its first try.

Group two faced a tougher task, Taylor says. “These crows had never pulled up a tool on a string before and they had never used one tool to get another tool,” he says. Instead, he says, they used their previous experiences of pulling up a string and using a long tool to get food to innovate a new behaviour [Australian Broadcasting Corporation]. Thus, it took the group two birds a little longer to crack the puzzle—sometimes multiple attempts. But in the end they all succeeded as well. In the video above, a bird named Sam figures it out.

The genius of crows comes as no surprise. A feature article in DISCOVER’s March issue, “Who You Callin’ ‘Bird Brain?‘,” documented the mind-blowing mental abilities of crows and other members of the corvid family. For example, British researcher Nicky Clayton’s scrub jays appeared to sense when they were being watched by competitors, and thus would return to their hidden caches of food and move them around in an attempt to thwart would-be thieves.

The researchers in the three-tool study have already seen New Caledonian crows whittle branches into tools, and a stream of other finds has shown that birds recognize themselves in the mirror, or, in a confirmation of an Aesop fable, use rocks to raise water level. The American preacher Henry Ward Beecher said that if men “bore black feathers, few would be clever enough to be crows”. Certainly, in a parliament of fowls, they would rule any roost [The Guardian].

Related Content:
DISCOVER: Who You Callin’ “Bird Brain”?
DISCOVER: Magpies Recognize Themselves in the Mirror
80beats: Not So Bird-Brained After All: Rooks Make And Use Tools
80beats: Mockingbird to Annoying Human: “Hey, I Know You”
80beats: Aesop Was Right! Birds Use Rocks To Raise Water Level

Video: Taylor et. al. / Proceedings of the Royal Society B

Thierry Legault is a French amateur astronomer… and if ever the word "amateur" were misleading, it’s here. Thierry is an incredibly accomplished astronomer; his pictures have graced my blog many times in the past. Like when he caught the Shuttle and Hubble silhouetted against the Sun, or this lighthearted picture of someone painting the Sun, or the Shuttle and the space station transiting the Sun.

Come to think of it, he seems to have a fetish with the Sun. But that’s good, because he’s done it again: he’s captured a record-breaking picture of the newest new Moon!

It’s very hard to see, so I bracketed it with those red lines. Thierry caught the Moon when it was as absolutely close to the Sun as it could get at the time, so in fact this is the youngest Moon it could possibly be!

So what does that mean?

Hopefully this terrible diagram I slapped together may help. Picture yourself on the Earth (that should be easy) marked by the E in the drawing. Once a day it appears that the Sun (yellow circle) circles the Earth (black path). The Moon (crescent symbol) circles the Earth once per month — well, it rises and sets every night, but relative to the Sun the Moon moves slowly across the sky. The Moon’s distance to the Sun changes so that at sunset every night, the Moon is in a noticeably different part of the sky than it was the night before.

New Moon is when the Moon and Sun are as close together as they can be, and it happens once per month or so. But since the Moon’s orbit is tilted, it doesn’t always pass directly in front of the Sun (creating a solar eclipse); it misses by a bit. But still, the Moon is so close to the Sun in the sky that we’re basically seeing the half of the Moon that’s unlit (the lit half is facing away from us, toward the Sun). When it’s offset a bit from the Sun, only the barest, slimmest bit of it is lit that we can see, producing an extremely emaciated crescent.

When you go outside and first notice the crescent Moon with your eye, it’s usually been a day or two since it passed its closest point to the Sun. The crescent is thicker, making it easier to see, and it’s farther from the Sun than at the exact moment of New Moon, reducing the glare. The closer the Moon is to the Sun, the thinner the crescent and the brighter the sky, making it doubly harder to catch. In Thierry’s case, he caught it when it was only 4.6 degrees from the Sun — only about 9 times the diameter of the Moon itself!

That’s why astronomers prize seeing the thinnest possible crescent; it’s a contest, like anglers catching the biggest fish or bird watchers seeing a rare species. It shows that the person involved has used a lot of skill and experience… and clearly Thierry has those!

This picture shows just how difficult Theirry’s setup had to be. Look how close to the Sun he was shooting! The screen blocks a lot of the glare from the sky, and the circular hole lets the ’scope see the Moon while cutting back on glare a little more. To reduce the sky brightness further he used an infrared filter; the sky doesn’t emit as much infrared light, so it appears a little bit darker, while the Moon does reflect IR (from the Sun), making it easier to spot. He used a filter that let through light at a wavelength at 0.85 microns, just a hair outside what the human eye is sensitive to.

Of course, he couldn’t see the Moon with his eye. So he aligned the telescope with the stars the night before to get it properly tracking the sky, and then used a computer program to aim the telescope at the position of the Moon. And obviously, it worked!

This was an amazing feat. And the only way to beat it is to catch the Moon at exactly that closest solar approach when the distance is actually smaller (or, if you like, closer to the point where the two paths of objects intersects on the sky). That’ll make this observation even harder… but I suspect Thierry’s already planning his next attempt.

Well now I can expand on yesterday's teaser. Here's the website for the conference. Note, it requires members of the interested public to register in order to attend. Meanwhile, here's the abstract of what we're going to be considering--which, I might add, is not being considered nearly enough:
The blogosphere represents a new kind of deliberative space that is both enlarging and constraining public discourse in unprecedented ways. The key factor about this space, the issue this workshop seeks to explore, is its lack of norms. It is an unruly space in the sense that there are no rules of entry, access, or conduct, except for extreme forms of behavior that are positively illegal. The consequences of this unruliness have been specially severe for scientific communication, which depends on common standards of truth-telling and civility for its progress. In turn, the erosion of scientific standards destabilizes the foundations of democratic deliberation. Can norms of discourse be inserted into the blogosphere that would advance science and democracy? Can blogs induce deliberation or must they encourage extremism and rage to the detriment of public reason? Is science helped or hurt by the new media? What particular distorting factors enter the picture as blogging becomes ...

For some animals, sex involves the ultimate sacrifice. Some species of spider, for example, redefine the concept of a dangerous liaison when the female turns around and devours her mate in a post-coital attack of the munchies. For males, it’s important that this act of sexual cannibalism isn’t in vain and that they die while impregnating the best possible mate. And for the wasp spider Argiope bruennichi, that means no sisters allowed.

Klaas Welke and Jutta Schneider from Hamburg’s Zoological Institute found that male wasp spiders are more likely to succumb to their grisly fate if they have just mated with an unrelated female than a sibling. Doing so allows them to avoid the heavy costs of inbreeding, where two copies of the same harmful or faulty genes have a high chance of ending up in the same individual. That’s bad news and both sexes do their best to avoid it, but for these spiders, the female holds all the cards.

She can mate with multiple partners and she can even control whose sperm actually fertilises her eggs. So the male must do everything he can in order to ensure that his genes pass on to the next generation. His job is even more difficult because he can only ever mate twice in his life. He has a pair of sexual organs – pedipalps – and each has only one use. And of course, his mate invariably attacks him after sex with murderous intent. Around 80% of sexual encounters end with the male becoming a meal and even if he survives his first time, the second time will kill him.

The male’s chances of living to mate again depend entirely on how long he lasts during his virgin encounter. If he jumps off the female within the first five seconds, he has a shot at survival. If he hangs around for more than ten seconds, he will almost certainly die. The trouble is that the longer he sticks around, the more sperm he can pump into the female and the greater his odds of fathering the next generation. It’s a tricky dilemma – with only two chances at mating, he should only make the choice to stay, inseminate and die if his mate is worth the trouble.

And according to Welke and Schneider, that’s exactly what happens. They found that males escaped being eaten almost half of the time (47%) if they were mating with their sisters, but just a fifth of the time (22%) if they mated with an unrelated female. This was directly related to the length of their flings – when they had sex with sisters, they left after 5.8 seconds but they kept at it for 9 seconds when it came to unrelated females.

Of course, it’s possible that this represents a choice on the part of the female – perhaps she cuts the male off early if he’s a relative. However, Welke and Schneider think that this is unlikely because females will attack any male regardless of how closely related he is. They get their say by choosing to mate with another male if they wish. The decision to end sex early appears to be the will of the male.

But why should a male mate with their sister at all, if she’s such an undesirably partner? The duo suggests that males lead precarious lives anyway, and the longer they spend searching for a mate, the greater their odds of dying before becoming fathers. So high is this risk that they’ll accept even undesirable mating opportunities; they’ll just try to move on to better things without getting eaten first.

Reference: Biology Letters http://dx.doi.org/10.1098/rsbl.2010.0214

More on cannibalism:

• March of the locusts – individuals start moving to avoid cannibals
• Attack of the pregnant cannibal fathers