There were plenty of signs that all was not right with the Macondo well before it exploded on April 20: The cement mixture that Halliburton had provided to seal it flunked every laboratory test the company had conducted. A pressure test on the well failed multiple times as well. There were indications that oil and gas had made their way into the well, which should have been sealed. But all of these warnings went unheeded—a tragedy, since they could have helped avoid the blowout, or at least given workers some time to prevent an accident from becoming a disaster.

On Monday, the chief counsel for the National Oil Spill Commission laid out a detailed timeline of the decisions—and missteps—that likely took place on the Deepwater Horizon rig to the commission. In the first of two days of hearings in Washington, counsel Fred Bartlit and his staff outlined a number of human errors and oversights that they believe led to a disaster that took the lives of 11 men and unleashed 4.9 million barrels of oil on the Gulf of Mexico. But "don't put too much import on any one event," Bartlit stressed, suggesting that it was the sum of these missteps that caused the event rather than any one decision (see the full list of preliminary conclusions here).

In what was painted as among the most dramatic failures, workers misinterpreted the results of a test of pressure in the well. On April 20, several tests indicated upward pressure in the well, a sign that the cement job was not was not properly containing the oil and gas. Yet BP and Transocean workers treated the test "as a complete success," the commission investigators concluded. "The question is why these experienced men on this rig talked themselves into thinking this was a good test result," said Sean Grimsley, assistant lead counsel for the Oil Spill Commission. "None of these men out on the rig wanted to die." 

According to BP workers on the rig that have talked to commission investigators, Transocean staffers blamed the pressure buildup on something called the "bladder" effect—which, according to their investigation, doesn't actually exist, said Bartlit. But figuring out why exactly this happened on that night has proven difficult, since several of the Transocean employees involved died in the blast, and two of BP's top men on the rig have declined to testify, invoking their Fifth Amendment rights against self-incrimination.

Bartlit did note, however, that while the negative pressure test is a crucial step in establishing that the well is stable, it is not required by federal regulations or industry standards, and there are no set procedures or training requirements when it comes to this test. Thus, BP and Transocean weren't even obligated to conduct this test in the first place.

Oil Spill Commission staff also spoke at length about indications that the cement mix from oil services giant Halliburton had failed numerous tests before it was used on this well. The commission's investigation has found that all studies of the mix completed before the explosion found it to be unstable. At the point when workers made the final moves to close the well, only the compromised cement barrier stood between the oil and gas and the Gulf.

Fishy Justice

Two cleaner wrasses, Labroides dimidiatus, working a sweetlips. Photo by Nhobgood, courtesy Wikimedia Commons.Two cleaner wrasses, Labroides dimidiatus, working a sweetlips. Photo by Nhobgood, courtesy Wikimedia Commons. New research out on one of my favorite subjects—cleaner fish and their mimics. For starters, here's a smart video showing the world of cleaners—fish and shrimp—and their clients in the seagrass beds and coral reefs off Papua New Guinea.

Symbiosis: Cleaner shrimp and Fish Clients from Lucy Marcus on Vimeo

Although half the animals waiting in line at a cleaning station are menu items for the other half, peace mostly prevails. That's because everyone needs the ministrations of those who eat parasites and clean messy wounds. One researcher, Redouan Bshary, has been investigating the relationship between cleaners and their clients for some years. Here's some of what I wrote about his findings in The Fragile Edge:

Cleaners do occasionally bite their clients too hard (some actually sneak a forbidden fish scale now and again), which can lead to them being chased away by the angry client. If the injured client returns later to this same cleaning station, the cleaner will spend the first few moments backing gently into him and massaging him with undulating caudal fins. The client appears to enjoy this, and the researchers conclude that it is an attempt at reconciliation—an apology, if you will, and the first of its kind seen in anything other than mammals on the order of primates, dolphins, sheep, goats, and hyenas. Bshary also discovered that cleaners are more likely to use caresses to mollify carnivorous fish who might eat them. But what of the nonpredatory client species, the vegetarians who can’t wield the ultimate threat? What is to stop the cleaners from nibbling their fish scales, or nipping a little muscle tissue, or slurping an energy-rich slick of mucus? Another study revealed that market forces shape the cleaner-client relationship. Curbing what might otherwise be an overwhelming temptation to imbibe some of the client’s protective mucus is the pressure of competition. Clients are less likely to visit cleaning stations where they have previously been cheated by the cleaner’s nibbling, or where they have had to wait in line. So even nonpredatory clients wield the big stick of consumer choice.
A dragon wrasse, Novaculichthys taeniourus, getting cleaned by rainbow cleaner wrasses, Labroides phthirophagus, on a Hawaiian reef. Photo by Mila Zinkova, courtesy Wikimedia Commons.A dragon wrasse, Novaculichthys taeniourus, getting cleaned by rainbow cleaner wrasses, Labroides phthirophagus, on a Hawaiian reef. Photo by Mila Zinkova, courtesy Wikimedia Commons.
Of course all good things come with their attendant thieves and con-fish. Some fish mimic cleaner wrasses—and not for the benefit of the clients. Again, from The Fragile Edge:
If you spend long enough in the company of cleaners on the reef you might find yourself a victim of one of the inevitable opportunists: the false cleaners, or mimic blennies, small fishes who make their living as cleaner mimics (some only in their juvenile phase). These little predators look uncannily like cleaner fishes, with blue stripes and long, narrow bodies. They even abandon their wriggly blenny swimming style for the cleaners’ characteristic rowing with the pectoral fins. Even more remarkable, some false cleaners have stolen the barbershop-pole display, the trademark of the cleaner wrasses, to lure the unsuspecting and the disheveled close by. When a victim falls for the ruse, the false cleaner charges, bites off a hunk of flesh with fangs hidden in its underslung lower jaw, then runs to hide in a cranny. The scale-eating blenny is renowned for darting up from the substrate and nipping at passing divers.

I like the Twilight Zone aura of this video from the golden age of wildlife melodramas. At any rate, it's a good illustration of the ways of the mimic blennies—even if it is a total set-up in a tank. (Question: Who cleans the mimics?)

Now Andrea Bshary and Redouan Bshary have a new paper out in Cell Biology describing how some victims of parasitic saber-tooth blennies spend valuable time and energy punishing their attackers by chasing them or biting them—even though there's no getting back that lost flesh.

So when does it make sense to punish, given that punishment has immediate energetic costs to both the punisher and the punished?

Well, according to the Bshary's experiments, the vengeful victims of blenny attacks serve themselves. That's because in future attacks blennies are more likely to go after different individuals than those who took the time and expended the energy to punish them. Yet the vengeful victims also serve other member of their own species. That's because, given a choice, blennies are more apt to switch to a different species of fish for their next attack if their previous victim punished them. Thus the vengeful victim creates a "public good." A third tier of research showed that at least some blennies can tell the difference between look-alike pairs of victims in which one punished them and the other did not, and will selectively bite the nonpunishers. From the paper's abstract:

A key challenge for evolutionary biologists is to determine conditions under which individuals benefit from a contribution to public goods. For humans, it has been observed that punishment of free riders may promote contributions, but the conditions that lead to stable cooperation based on punishment remain hotly debated. Here we present empirical evidence that public goods may emerge as a by-product of self-serving punishment in interactions between coral reef fishes and parasitic saber-tooth blennies that stealthily attack their fish victims from behind to take a bite. We first show that chasing the blenny functions as punishment, because it decreases the probability of future attacks. We then provide evidence that in female scalefin anthias, a shoaling species, punishment creates a public good because it increases the probability that the parasite switches to another species for the next attack. A final experiment suggests that punishment is nevertheless self-serving because blennies appear to be able to discriminate between look-alike punishers and nonpunishers. Thus, individuals that do [not?] contribute to the public good may risk being identified by the parasite as easy targets for future attacks.
[I'm assuming the "not" was left out of that final sentence...?]

'Cleaner' Pt. 2 from MORPHOLOGIC on Vimeo.

Finally, here's another memorable video from Morphologic showing a Periclemenes pedersoni shrimp cleaning its host sea anemone, Ricordea florida corallimorphs.

The paper:

Crossposted from Deep Blue Home.

I have a piece up on the main site today about the coming climate science witch hunt now that Republicans will be back in control of the House next year.

In what I took as a sign of hope, the Los Angeles Times reported this morning that the American Geophysical Union plans to launch a coordinated effort to push back against climate change deniers. But now AGU says that story is "inaccurate." While the group says it is planning to re-launch a climate science Q&A program it started last year for journalists covering the United Nations climate summit in Copenhagen, there is no wider program to defend the science in the works:

"In contrast to what has been reported in the LA Times and elsewhere, there is no campaign by AGU against climate skeptics or congressional conservatives,” says Christine McEntee, Executive Director and CEO of the American Geophysical Union. “AGU will continue to provide accurate scientific information on Earth and space topics to inform the general public and to support sound public policy development."
AGU is the world's largest, not-for-profit, professional society of Earth and space scientists, with more than 58,000 members in over 135 countries. "AGU is a scientific society, not an advocacy organization,” says climate scientist and AGU President Michael J. McPhaden. "The organization is committed to promoting scientific discovery and to disseminating to the scientific community, policy makers, the media, and the public, peer-reviewed scientific findings across a broad range of Earth and space sciences.&quote

I'm disappointed that the leading scientific professional group for climate scientists isn't taking up the effort outlined in the Times. But more importantly, I'm troubled by the idea that AGU set up in this press release by creating a delineation between "a scientific society" and "an advocacy organization." This statement makes it appear that any effort to fight skeptics on climate science would by nature be "advocacy" work, and that a scientific group, by extension, should not then participate in it.

This only serves to affirm the talking point of climate change deniers that scientists who take the time to explain the science and refute lies and misinformation are engaging in "activism." The repetition of this false association by such an esteemed scientific group is problematic.

UPDATE: The Guardian gets the story right. AGU is relaunching its climate Q&A program, and a separate group of climate scientists is planning the rapid response effort. More here. Glad this other effort I underway, though I still think that the wording in the AGU release is troubling. That said, both this outside effort by climate science titans like Kevin Trenberth of the National Center for Atmospheric Research and Michael Oppenheimer of Princeton University, and the AGU work are invaluable tools in the communication battle over climate science.

You know the Environmental Working Group's super-helpful list of the most-pesticide-laden fruits and veggies? Well, there's a Big Ag lobby group called the Alliance for Food and Farming that's trying to debunk it. And the USDA just gave the lobbyists $180,000 to aid their smear campaign, The Atlantic reports.

So exactly who's behind the Alliance for Food and Farming? According to SourceWatch, its board of directors includes honchos from the California Strawberry Commission, the California Tomato Farmers, the Produce Marketing Association, and the California Association of Pest Control Advisors, among other industry groups. The AFF's main argument: "Promotion of the 'Dirty Dozen' list actually makes the work of improving the diets of Americans more difficult because it scares consumers away from the affordable fruits and vegetables that they enjoy."

Riiiight. Considering that the EPA freely admits that pesticides can cause "birth defects, nerve damage, cancer, and other effects," it's totally boneheaded to suggest that raising consumer awareness about pesticides is making Americans less healthy. What's more, it's not like the Environmental Working Group is suggesting you give up on produce entirely and stock your fridge with Mountain Dew instead. In fact, EWG explicitly states that the list isn't meant to discourage people from eating their veggies. From the FAQ

Do all these pesticides mean I shouldn’t eat fruits and vegetables?

No, eat your fruits and vegetables! The health benefits of a diet rich in fruits and vegetables outweigh the risks of pesticide exposure. Use EWG's Shopper's Guide to reduce your exposures as much as possible, but eating conventionally grown produce is far better than not eating fruits and vegetables at all.

The bottom line: The more you know about your food, the better. Period.

Here's a refresher on the EWG's "Dirty Dozen" and "Clean 15":

Got a burning eco-quandary? Submit it to Get all your green questions answered by visiting Econundrums on Facebook here.

The immensely popular Harry Potter films (and books) have taken their toll on owls. In the series, owls are children's pets and the postal service. Harry Potter's snowy owl, Hedwig, has a fan base of her own and is depicted as a clever, loving animal. This week, India's minister of the environment blamed Potter's popularity for boosting the illegal bird market in his country. "Following Harry Potter, there seems to be a strange fascination even among urban middle classes for presenting their children with owls," minister Jairam Ramesh told the BBC. Ramesh isn't the only one noticing the trend: in the UK, there is now a shelter for the owls dumped by owners when the magic of caring for a large raptor wore off. Shelter operator Don Walser told the Telegraph that he is rehabilitating owls from all over England, and is particularly dismayed by "a pair of snowy owls that were left in a garden by their owners for three days without food. They would have died. It was disgusting."

Harry Potter inspired one ornithologist to do a comprehensive study of the owl trade in India. His report, out this week from the wildlife conservation group Traffic, describes a situation in which the author was asked to procure an owl by a friend's wife. "This was probably one of the strangest demands made to me as an ornithologist," author Abrar Ahmed wrote. The wife of a friend wanted live, white-colored owls for her 9-year-old son's Harry Potter-themed birthday party. "Please ask someone to capture and bring the owl to us," she asked Ahmed. "We can pay the cost." The woman was seemingly unaware of the penalties for trafficking wildlife, but was persistent. In the end, Ahmed didn't bring live owls, but instead drew pictures of snow owls and hung them around the party venue. Later in the night, he was able to show children a real live owl when one happened to land near the gate of the venue. It wasn't a snowy owl like Hedwig, it was a Spotted Owlet, but it was real and the children could see it without participating (albeit unknowingly) in illegal wildlife trafficking. After the party, several guests joined local birdwatching groups.

Posts on health, the environment, and climate from our other blogs.

No Fun Zone: San Francisco bans including toys with high-calorie, high-fat foods like Happy Meals.

Political Climate: Why climate scientists can't ignore politics, even if they want to.

In the Black: Even after paying for the Gulf spill, BP still posted a profit.

Ivory Towers: An academic breaks rank, calling for more climate scientist accountability.

Bad to the Bone: US health care is expensive, but at least it works... right?

Unhealthy End: Bad news for Democrats who supported health reform at the last moment.

Obamacare Scare: A scary cartoon about Obamacare, with animation.


I lamented the demise of the eco-friendly SunChips bag last month, a relatively trivial issue but one that I think is indicative of chip-eating Americans' unwillingness to accept even the slightest discomfort for the good of the environment. The noisy bags were simply too much for us to bear, leading Frito Lay to bag the bags. But it looks like our neighbors to the north are keeping them.

The company's Canadian division posted this public service announcement from sustainability chief Helmi Ansari letting citizens know they are keeping the compostable bags up north. It seems Canucks are OK with "a little more noise for a little less waste."

Republican Sen. Lisa Murkowski hasn't even officially won her bid for reelection in Alaska, but she's already reviving to block a pending Environmental Protection Agency plan to regulate greenhouse gas emissions.

On Wednesday, President Obama said that EPA regulations loom on the horizon in 2011, in the absence of an alternative produced by Congress. While Obama said he's not wedded to cap and trade legislation to curb emissions, he stressed that the administration is committed to doing something on the issue.

In response, Murkowski's office blased out a statement Thursday renewing her call to take the EPA regs off the table:

There are a great number of things we can do to responsibly reduce our carbon emissions without burdening our economy with an unworkable cap-and-trade scheme or command-and-control regulation by the EPA," Murkowski said. "Many of those policies, including investment in renewable and alternative energy technology, increased efficiency, and expanding our nuclear power options were included in the comprehensive bill I helped pass out of the Energy Committee more than a year ago.
If the president wants to start with the work the Energy Committee has already done, I would be happy to work with him. But I also believe we must first preempt the EPA from meddling in the work of Congress when it comes to setting climate policies.

Murkowski, whose conflicted climate stance we profiled here, has made several previous attempts at blocking EPA regulations. Her last one failed in June, but it had the support of six Democrats. Significant Republican gains in the Senate certainly increase the possibility that a similar block could pass this year, though Obama would likely veto it.

With Republicans claiming the majority in the House, it's fair to say that the committees with oversight of key energy and environmental issues will be quite different in the 112th Congress. The new chair of the powerful Energy and Commerce Committee is still up in the air, but it looks all but certain that Doc Hastings (R-Wa.) will assume the chairmanship of the Natural Resources Committee.

Hastings, a former paper company executive, is the currently the senior GOP member of a subcommittee that oversees federal land and water issues;  it also has a big say when it comes to issues including oil and gas drilling, mining safety, endangered species, forests, and fisheries. Within hours of the GOP victory, he sent out his list of priorities as chair of the panel. The top goal: "cutting spending and bringing fiscal sanity back to Washington, D.C."

As for goals on the subjects that he would have jurisdiction over, Hastings pledged to push for the oft-repeated Republican catch phrase, "an all-of-the-above energy plan." Translation: more oil drilling, mining, etc. Here's what he outlines:

Creating new jobs and giving a much needed boost to the economy will also be at the forefront of our agenda. Through the responsible stewardship of our natural resources we can put Americans to work, strengthen our economy and protect the environment. This includes increasing domestic energy production through an all-of-the-above energy plan and ensuring that public lands are actually open to the public. The livelihoods of rural communities, especially in the West, are dependent on the smart use of our public lands, water, timber, minerals and energy resources.

Hastings also pledged to "provide much needed oversight of the Obama Administration’s policies that have largely gone unchecked for nearly two years" and "hold the Administration accountable." He specifically targeted the temporary moratorium on new offshore drilling imposed after the BP spill in the Gulf (which was dropped last month), arguing that there is still a "de facto drilling moratorium" due to the implementation of new regulations and standards. He accused the administration of having "plans to lock up vast portions of our oceans through an irrational zoning process."

Hastings has received plenty of financial support from energy and natural resource interests like the National Rural Electric Cooperative Association and the timber giant Weyerhaeuser Co. over the years, as the Center for Public Integrity details here.

"He's not a friend of our public lands, and when it comes to oil and gas he wants to take us exactly in the wrong direction," said Athan Manuel, director of the public lands program at Sierra Club. "From what we can tell he hasn’t learned a thing from the Deepwater Horizon spill. He seems to want to charge ahead and lease as many areas as possible, even though we've seen that the oil companies can't be trusted with our coastal ecosystems."

Manuel noted that Hastings even blocked an effort to protect wilderness areas in Washington State offered by his Republican colleague, Dave Reichert. "If that's how he treats his fellow Washington State Republican, I'm not optimistic," said Manuel.

Offshore drilling is the most relevant issue that the committee could weigh in on in the near future. Under current chair Nick Rahall (D-W.Va.), the panel passed a strong spill-response package in July. But the Senate didn't pass its companion bill, leaving major uncertainty as to whether Congress will do anything in response to the Deepwater Horizon disaster. The Senate could still move the bill in lame duck, but it's doubtful that any new regulations are going to come in this committee under Hasting's watch next year.

Close-up of live mushroom coral taken by James Nicholson of the Coral Culture and Collaborative Research Facility, South Carolina. This image took 13th place at the 2010 Nikon Small World Close-up of live mushroom coral taken by James Nicholson of the Coral Culture and Collaborative Research Facility, South Carolina. This image took 13th place at the 2010 Nikon Small World Photgraphy Contest. To read about a renowned mycologist's quest for a mushroom that could save the world, click here. For more mushroom photos, click here.

Mushroom corals are members of the Fungiidae, a family of interesting marine animals in the phylum Cnidaria, which includes corals, anemones, and jellyfish, as well as some aquatic species. Unlike the more familiar stony, or reef-building corals, most mushroom corals are not polyps roughly the size of ants living together in colonies that take the form of, say, staghorn corals.

(Heliofungia actiniformis. Photo by Samuel Chow, courtesy Wikimedia Commons.)Heliofungia actiniformis. Photo by Samuel Chow, courtesy Wikimedia Commons.

Instead most are free-living solitary polyps that grow to relatively enormous sizes. Heliofungia actiniformis (above) can reach 50 centimeters/20 inches in diameter. Believe it or not, the photograph above is of a single polyp.

(Fungia fungia. Photo by Jon Zander, Digon3, courtesy Wikimedia CommonsFungia fungia. Photo by Jon Zander, Digon3, courtesy Wikimedia Commons

Many mushroom corals look dead or bleached until their tentacles emerge, generally after dark.

(Photo by Silke Baron, courtesy Wikimedia Commons.)Photo by Silke Baron, courtesy Wikimedia Commons.

They share some interesting traits with their terrestrial (mostly) namesakes, the fungi, or mushrooms. Shape obviously. Though mostly it's the juvenile fungiids, growing on stalks, that resemble terrestrial fungi. Sorry can't find any pictures of them.

(Lycoperdon perlatum. Photo by Dohduhdah, courtesy Wikimedia Commons.)Lycoperdon perlatum. Photo by Dohduhdah, courtesy Wikimedia Commons.

Mushrooms of the land are also amazing organisms. Enough so as to warrant a kingdom all their own, the Kingdom Fungi, separate from the plants, the animals (including mushroom corals), and the bacteria.

(Photo by Dohduhdah, courtesy Wikimedia Commons.)Photo by Dohduhdah, courtesy Wikimedia Commons.Genetically, mushrooms are more closely related to animals than plants.

 (Portobello mushroom, Agaricus bisporus. Photo by Chameleon, courtesy Wikiemdia Commons.) Portobello mushroom, Agaricus bisporus. Photo by Chameleon, courtesy Wikiemdia Commons.

This seems pretty obvious to anyone who dines on mushrooms. A portobello—which is simply the older fruit, or pileus, of a button and a crimini mushroom—is downright meaty tasting.Photo by cyclonebill, courtesy Wikimedia Commons.Photo by cyclonebill, courtesy Wikimedia Commons.Of late, a few discoveries about mushrooms are bending our notions of time and space in the living world.Armillaria ostoyae. Photo by Eric Steinert, courtesy Wikimedia Commons.Armillaria ostoyae. Photo by Eric Steinert, courtesy Wikimedia Commons.

A clonal colony of honey mushrooms (Armillaria ostoyae) in Oregon has been found to extend across more than 965 hectares/2,384 acres of forested mountains.

The colony is estimated at between 1,900 and 8,650 years old.

The unreleased spores of a morel mushroom {Morchella elata} magnified 40 times. Photo by Peter G. Werner, courtesy Wikimedia Commons.The unreleased spores of a morel mushroom {Morchella elata} magnified 40 times. Photo by Peter G. Werner, courtesy Wikimedia Commons.

The reproductive strategies of the Kingdom Fungi are equally exuberant. Many species reproduce sexually and/or asexually, depending on the stages of their life cycle and on environmental triggers.

In sexual reproduction, compatible individuals may combine by fusing their threadlike hyphae (the parts we usually don't see, underground or inside rotting trees) together into an interconnected network. As if humans mated by first fusing our bloodstreams.

The video below highlights, with the help of lasers, tiny mushroom spores.

Secret Sounds of Spores: Introduction from The Amazing Rolo on Vimeo.

The second video is part of the same ongoing beautiful fusion of art and science hyphae. Wish I could get to Edinburgh to see the installation.

The Boroscilloscope from The Amazing Rolo on Vimeo.

The release of mushroom spores is spectacularly reminiscent of spawning corals.

In the photo below you can see the tiny orange eggs being released by a female mushroom coral (Fungia scutaria) spawning at the Hawaii Institute of Marine Biology in Oahu. Looks kind of psychedelic.

Photo by Dr. Dwayne Meadows. From the NOAA photo library.Photo by Dr. Dwayne Meadows. From the NOAA photo library.Photo by Dr. Dwayne Meadows. From the NOAA photo library.

Researchers from Japan recently discovered that mushroom corals can change sex and back again, a talent known as sequential hermaphroditism. It's not all that unusual in the deep blue home. Some of the echinoderms, like urchins and sea stars, along with some of the crustaceans, mollusks, and bristle worms gender shift every which way too.

In the mushroom corals studied so far, the smaller individuals are generally males and the larger individuals females. This makes sense when you consider the different time-and-energy investment required to make eggs versus sperm.

Mushroom corals, in their adult form, do have the ability to move, albeit very slowly, via three known mechanisms: by regulating buoyancy and floating away; by growing a hydromechanically adapted shape and floating away; or by creeping away. Motility enables them to seek out the sunniest locations on the reef—sunlight fuels their endosymbiotic bacteria—and to escape being overgrown by other corals.

But might they be sprightlier than we think? Recently mushroom corals living in the Gulf of Aqaba were observed eating moon jellyfish (Aurelia aurita). How did they procure the wandering jellies? No one knows.

The papers:

  • B. A. Ferguson, T. A. Dreisbach, C. G. Parks, G. M. Filip, and C. L. Schmitt. Coarse-scale population structure of pathogenic Armillaria species in a mixed-conifer forest in the Blue Mountains of northeast Oregon. Can. J. For. Res. 33(4): 612–623 (2003). DOI:10.1139/x03-065.
  • Yossi Loya and Kazuhiko Sakai. Bidirectional sex change in mushroom stony corals. Proc Biol Sci B. 2008 October 22; 275(1649): 2335–2343. DOI: 10.1098/rspb.2008.0675.