Nibbled to distraction: Gerbils infested with fleas don't watch for foxes

In natural communities, each species is embedded in a web of interactions with other species—predators, prey, competitors, mutualists, and parasites. The effects of all these other species combine in complex, unpredictable ways. I recently discussed a study of protozoans living inside pitcher plants that found predators and competitors can cancel out each others' evolutionary effects. Now another study finds that parasites and predators can interact to make desert-living gerbils adopt less effective foraging strategies [$a].

Allenby's gerbil is a small desert rodent native to Israel's Negev Desert. They make a living foraging for seeds, which might seem simple enough—but for small desert mammals, it's a constant balancing act. Foraging requires continuously judging how profitable it is to continue gathering seeds in one spot compared to looking for another, maybe better, spot; and all the while watching out for predators.

The red fox—a major threat if you're a tiny rodent, but hard to watch for when you're scratching fleas all the time. Photo by HyperViper.

Running the race

Well, I've successfully run the Seattle Marathon. I finished in 3 hours, 31 minutes, and 27 seconds, which is a pretty nice improvement over last time, in Portland.

Coming down the home stretch. Photo courtesy my cousin Adrienne.

I've had a nice hot shower, and my cousin—with whom I'm staying while in Seattle, and who came to watch me cross the finish line—keeps pressing protein-and-vitamin recovery shakes on me, so I'm actually feeling pretty good. It's great end to a great fall break in Vancouver and Seattle. I took a lot of photos—there's a slideshow after the jump.

Science online, Black Friday edition

There may be more going on in those tiny heads than you think. Photo by shadarington.

• Attention, bacon fans. Epileptic seizures can be controlled by an ultra-high-fat diet. (NY Times)
• A few mg of prevention. Men who have sex with men can substantially reduce their risk of HIV infection by taking antiretroviral drugs. (NY Times, Dan Savage; original article in The New England Journal of Medicine)
• Oh, now you tell us. Turkeys have enough social intelligence to recognize other turkeys from their own social group. (Jason Goldman for Scientific American)
• Mmm. Cranberry genomics. Jason Goldman rounds up Thanksgiving-themed online science writing. (The Thoughtful Animal)
• Meta-blogging science? The fellows behind Obesity Panacea have launched a blog about science blogging. (Science of Blogging)
• A pithy comment is beyond the scope of the present linkfest. Incremental publication can be a good thing. (DrugMonkey)
• Well, that was easy. A simple 15-minute writing assignment closes the "gender gap" between male and female physics students. (Not Exactly Rocket Science)
• To be fair, science is pretty difficult. The leadership of the American Anthropological Association is moving to remove references to science from the organization's mission statement. (Fetishes I Don't Get)

And finally, Robert Krulwich narrates a beautifully animated short film about an enduring mystery of human behavior: our inability to walk in a straight line without help from visual cues.

No, I will not run the Seattle Marathon barefoot

I'm spending a significant chunk of my Thanksgiving break in Seattle, for the purpose of running what will be my second marathon this weekend. Running, like cooking, is helping to keep me sane in the midst of teaching labs, finishing my dissertation research, writing said research up for publication, and trying to sort out what happens after my committee decides I've earned a handful of extra letters after my name.

Me at about mile 17 in last year's Portland Marathon. I'm not quite dead yet.

My first marathon was last year's Portland Marathon. Prior to 2009, I'd never run a race longer than five miles, but then that spring I let friends talk me into a half-marathon, and after running more than 13 miles, 26.2 suddenly didn't seem quite so insane. Even so, training up for Portland was more than enough to make me realize that running what was (for me) a 3 hour-45 minute course is not really the same thing as running eight or nine 5k's in a row.

Feed me!

I can make it through even a half-marathon on a good breakfast and carefully-judged pre-race hydration, but to go much longer I need more food (and water) mid-run. The long-term exercise involved in a long race is fueled by a combination of fat reserves and glycogen stored in the liver and muscle tissue. Glycogen is the more efficient fuel, so as exercise intensity increases, muscles draw on it more heavily.

The Carnal Carnival comes again

Based on a careful analysis of D&T visitors over the past month, I conclude that orgasms are a popular topic.

Absolute unique visitors per day, tabulated by Google Analytics..

So perhaps you folks would be interested in an entire blog carnival about orgasms? I think this is very likely. Fortunately for you, orgasm is the theme of this month's Carnal Carnival, hosted with great enthusiasm by Scicurious. Enjoy!

Science online, sociable tortoises edition

Hey, there! Photo by hankplank.

"Sociable tortoises" would make a pretty good name for a band. I assume they'd be somewhere in the genre phenotype space between Vampire Weekend and The Decemberists.

• Call it the "smugness threshold." Higher income is only associated with greater emotional well-being up to a point—but past that point, people with higher incomes still report greater perceived happiness. (Neurotic Physiology)
• Heads up! Tortoises follow the gaze of other tortoises, indicating unexpected social intelligence. (The Thoughtful Animal)
• Who knows what a fish is thinking? Siamese fighting fish will famously attack other fish or their own mirror images with equal vigor—but their brains express different genes when looking at their own images! (NeuroDojo)
• Best paleontological reconstruction illustration ever. Pterosaurs may have launched into the air by "vaulting" on their arms, not jumping with their teeny-tiny legs. (80 Beats)
• Phylogenies on the witness stand. Ed Yong surveys the use of evolutionary trees as evidence in legal cases. (Not Exactly Rocket Science)
• Can't wait to see the phylogeny of the Septuagint. Texts, especially hand-copied manuscripts, mutate over time in much the same way as DNA. (The Atlantic)
• Especially in Hitchcock's classic "To Catch a Prairie Dog." Film scores contain sound patterns strikingly similar to animal alarm calls. (Wired Science; original article at Biology Letters)
• We are also the beaver. New analysis of fossils identifies the sister group to Castor, the genus containing modern beavers. (Open Source Paleontologist; original article on PLoS ONE; interview with one of the authors)
• That's what undergrad field assistants are for. A classic study of bitter taste as predator deterrent had students taste-testing tadpoles. (Wonderland)

Apparently trying to top the transcendent union of "Star Trek" and Monty Python, the Internet presents Harry Potter singing Tom Lehrer. I'll admit, this upgraded my opinion of Daniel Radcliffe from "Hollywood nerd" to "nerd."

Public Radio, the rap

Via @johnmoe. Brilliantly written and packed full of clever detail ("I'd buy a Prius if I could afford it"), but I especially love the use of the "All Things Considered" theme.



(Only complaint: where's the love for RadioLab and On the Media?)

Is female orgasm adaptive? Let's ask the clitoris.

Correction, 22 December 2010: Vincent Lynch, author of the second paper discussed in this post, notes in the comments that he didn't actually conclude that female orgasm was an adaptation. I've corrected the post accordingly.

Whether or not a trait is an adaptation, shaped by natural selection for a specific function, can be a surprisingly contentious question in evolutionary biology. When the trait in question belongs to human beings, though, "contentious" reaches a whole new level—because when evolutionary biologists consider humans, their conclusions get personal.

Erotic sculpture on temple wall, Khajuraho, India. Photo by Abhishek Singh aka Bailoo.

Among the myriad traits and behaviors of Homo sapiens evolutionary biologists might choose to study, few can be as personal as the female orgasm. The adaptive function of male orgasm is about as clear-cut as possible—it's a mechanistic necessity for uniting a sperm with an egg. But while female orgasm is enjoyable (or so I am told; this is as lousy a point as any to admit that my expertise in this phenomenon is purely academic), it isn't necessary for fertilization. No man can be a father without having had at least one orgasm, but a woman could conceivably give birth to a huge family without having any.

To explain the existence of female orgasm in an evolutionary context, then, biologists have two options: (1) discover a way in which female orgasm shapes reproductive success indirectly, or (2) conclude that female orgasm isn't an adaptation. Possibilities advanced for the first option range from the benefits of closer bonding with a mate—sex is, after all, about more than mere reproduction—to suppositions that the contractions associated with orgasm help draw semen into a woman's reproductive tract.

Science online, oily coral edition

Photo by ucumari.

• Is anyone really surprised? Biologists working with NOAA have found the first clear evidence that the Gulf of Mexico oil spill is damaging coral reefs. (Deep Sea News)
• Drink the corn liquor, let the Ritalin be. Could Ritalin help fight cocaine addiction? (Neurotic Physiology)
• Trade-offs are a bitch. Adaptation for swimming and seal-hunting has made the polar bear's skull structurally weaker than those of its closest relatives. (Not Exactly Rocket Science)
• Admixture is fun! Razib Khan examines genetic studies of major human ethnic groups. (Gene Expression)
• Gotta get funded to do the science. Over at dechronization, Rich Glor lays out tips on writing a doctoral dissertation improvement grant. (Part 1, Part 2, Part 3, Part 4 Part 5)
• Scientific support for the siesta. A daytime nap can improve memory performance. (BrainBlogger)
• Hint, hint. Submissions for the Open Lab 2010 collection of online science writing close at the end of the month. (The Thoughtful Animal)
• This just in. Eating fewer calories than you burn results in weight loss—even when most of those calories are in Twinkies. (Weighty Matters)
• Because you can't develop Seasonal Affective Disorder if your brain is too small. Lemur species that live in habitats with greater seasonal changes have larger brains. (NeuroDojo)
• Paging Dr. Pangloss. Psychologists are surprised to discover that the sight of cooked meat makes men less aggressive. They will no doubt also be surprised to find that it makes men ask for a fork and A-1 Sauce, too. (AOL News, McGill University press release)
• Science is impossible. But that's okay. Really. (We, Beasties)

The Internet has now achieved its purpose

I mean, once you've mashed-up Star Trek and Monty Python, what is there left to do? Nothing. There is nothing left to do.



(Via Mr. Gunn.)

In the depths of a pitcher plant, competitors and predators cancel each other out

Species interactions are probably pretty important, in the evolution of life. There are all sorts of studies showing that the fitness and evolutionary history of individual species depends upon interactions with pollinators, symbiotes, food plants, herbivores, parasites, predators, and competitors. Most of these studies focus in on a single interaction—but what living thing interacts with only one other organism? Coevolution, when it happens, happens in a community context.

Adding even a second interaction into the scientific picture can be difficult, but it may also dramatically change the evolutionary outcome, as seen in a new study of evolution in the protozoan communities living in purple pitcher plants. Individually, competitors and predators are significant agents of natural selection—but together, they seem to counterbalance each other [$a].

The purple pitcher plant, Sarracenia purpurea. Photo by petrichor.

Carnivorous pitcher plants grow funnel-shaped leaves that collect water to form a pitfall trap for hapless insects, which provide a source of nitrogen in swampy, nutrient-poor habitats. One species' pitfall is another's ideal habitat, however, and pitchers also play host to diverse micro-communities [PDF] of protozoans, bacteria, and even mosquito larvae. By recreating—and experimentally manipulating—these communities in the laboratory, the new study's author, Casey terHorst, was able to disentangle the individual and combined effects of two different kinds of species interaction within pitcher plant pitfalls.

Fake science

It's all fun and games until a Republican Senator uses your hilarious fake infographics to prove that climate change is a hoax. But until then, enjoy. (Hat tip to Doc Becca.)

Image via Fake Science.

I am still laughing at the one about bees' social organization.

"Lab Romance"

Submitted as further evidence in support the point I have previously made regarding the general gay-friendliness of academic biology.

Science online, miracle cure edition

Photo by rpongsaj.

• Or, you know, the evolution of a super-cold. The discovery of a new way to stop viruses after they've already invaded cells could lead to an actual cure for the common cold. (The Independent)
• Pleistocene Park, anyone? An extremely well-preserved mammoth skeleton unearthed near Denver, Colorado, may contain reasonably intact DNA. (The Denver Post)
• Not just because of running to catch the bus. People who use public transit tend to be more active in general. (Obesity Panacea)
• What the !?%$#**! do we know about human mutation rates, anyway? Less than you might think. (John Hawks Weblog)
• This confirms what I already believe about both anti-vaxxers and corporate PowerPoint use. A GlaxoSmithKline presentation on the importance of vaccination leaves Jason Goldman pondering cognitive bias and the vital importance of good PowerPoint use. (The Thoughtful Animal)
• All part of a conspiracy by socialist Radiolarians. Analysis of carbon isotopes in sediment cores suggest that a period of climatic warming in the middle Eocene was caused by increased atmospheric carbon dioxide. (Scientific American)
• WTF is hepato-splen? That's just one of many questions Scicurious can't answer about a truly bizarre study investigating the effect of lunar phases on women's menstrual cycles. (Neurotic Physiology)

Video this week, via io9: German researchers have determined that bats recognize bodies of water by echolocation because, when presented with a metal plate that reflects sound the way water does, they try to drink from it.

Between two host plants: The middle road doesn't work for hybrid butterflies

New species form when separate populations of related organisms are no longer able to interbreed. Reproductive isolation can arise if two populations evolve different mating behaviors, or lifestyles so different that individuals from different populations don't even encounter each other—but it need not mean that matings between the two populations never occur. In fact, speciation can arise in the face of quite a lot of interbreeding, so long as the hybrids produced by interbreeding are less fit than "purebred" individuals.

Edith's checkerspot in Mount Diablo State Park, California. Photo by davidhoffman08.

This is what seems to be occurring in populations of Edith's checkerspot, a small butterfly native to Western North America. Checkerspot populations in California use a wide variety of different host plants, and a recent study has shown that the offspring of parents from different host plants are maladapted in the wild.

Election night

With all due respect to Mr. Stewart, the Python lads nailed election night coverage to the wall decades ago.



If you haven't already done so, fellow U.S. citizens, please hurry up and find your fucking polling location so you can vote for the Sensible candidate. Need help remembering what the fuck a Sensible government did for you in the last two years? There is also a site for that—more detail, with less swearing, is here.

Carnival of Evolution No. 29

Photo by Tambako the Jaguar.

The 20th edition of the Carnival of Evolution is now online at Byte Size Biology—where the compilation of evolution-themed online writing is given a sporting spin. Check it out!

The grad student's cookbook

Scicurious has officially posted her epic compilation of recipes by and for graduate students, i.e., compiled with budget and preparation time in mind. (I put my contribution online early.) They're neatly sorted by meal—breakfast, lunch and snacks, dinner, desserts, and Ramen.

If you don't understand why Ramen is a meal in itself, well, consider yourself lucky. Otherwise the range, which runs from pot roast to Pad Thai, is impressive and delicious. The lesson I take away is that (surprise!) it's entirely possible to cook well and simply on a budget—you only need to decide to do it.

Really, my fellow graduate students, you can do better than this. Photo by pinprick.