Month: August 2009

They can’t start too early!

August 22, 2009 • 1:34 pm

I have a four-year-old fan! An alert reader writes:

Dear Dr. Coyne,

I am writing to let you know how much I am enjoying reading your book ‘Why Evolution Is True.’ While I have long been interested in the sciences my eyes have been opened even farther with the evidence this book presents.

And if it wasn’t enough that I am enjoying your book, my 4 year old son keeps stealing it from me at every opportune moment. He can’t seem to get enough of all the pictures and diagrams in the book. He is particularly fond of the diagram near the beginning of the book that shows the evolutionary change from reptiles to dinosaurs to birds. Since I have explained the diagram to him he now goes around telling everyone that birds came from dinosaurs. You can never start teaching them science and critical thinking too early!

I’ve attached a picture I thought you might enjoy.

A young fanFig. 1. Evoutionist in statu nascendi.

The Asian giant hornet

August 22, 2009 • 10:37 am

In WEIT, I begin the chapter on natural selection with a particularly gruesome example of an adaptation: the predatory Asian giant hornet (Vespa mandarina), the world’s largest wasp and a viscious killing machine.

They are horribly fricking huge, with a two-inch body (tipped with a quarter-inch stinger that injects a potent venom) and a three-inch wingspan. Their stings kill several dozen Asians yearly. Here’s what they look like:

mandarinia2

Fig. 1. Vespa mandarina on a brave Homo sapiens.

I won’t recount the whole story here, except to say that a small band of these wasps, incited by a single scout wasp, who finds a nest and marks it for doom by depositing a drop of pheromone that attracts its confreres, can decimate a colony of 30,000 Asian honeybees in a few hours, decapitating the hapless bees with their slashing jaws. They then raid the bee colony of honey and grubs, which they bring back to their own nests to deposit in the maws of their own voracious larval wasps. Here’s a video of a wasp raid:

But the local honeybees have evolved a marvelous counter-adaptation: they mob the first scout wasp that tries to mark the beehive with a pheromone, covering the wasp with a thick ball of bees that vibrate their abdomens, raising the temperature inside the ball so high that the hornet is cooked to death (the bees can survive that temperature). Here’s a video of the cooking process:

As one might expect, the introduced European honeybee, which hasn’t coevolved with the Asian wasp, has no counteradaptation.

A relative of the hornet, the not-quite-so-dangerous species Vespa veluntina (also a predator of honeybees) , has invaded Europe in the last few years, as reported this week in the Telegraph:

The bee-eating hornets, instantly recognisable by their yellow feet, are rapidly spreading round France and entomologists fear that they will eventually cross the Channel and arrive in Britain.

Hundreds of the insects attacked a mother on a stroll with her five-month-old baby in the Lot-et-Garonne department, southwestern France, at the weekend before turning on a neighbour who ran over to help. The baby was unharmed.

They then pursued two passers by and two Dutch tourists on bikes. The victims were treated in hospital for multiple stings, which are said to be as painful as a hot nail piercing the skin

. . .The Vespa velutina, which grow up to an inch in length, is thought to have arrived in France from the Far East in a consignment of Chinese pottery in late 2004.

So far the honeybees in Europe, like the European honeybees in Asia, have no defenses against the wasp. It will be interesting to see if, over time, they evolve a cooking behavior (or, in the case of some honeybees in Cyprus, a variant in which a mob of bees surrounds the wasp and suffocates it by preventing it from expanding and contracting its abdomen).

Caturday felid, now with dino!

August 22, 2009 • 6:26 am

Bruce Woollatt, who posts under the handle “Your name’s not Bruce?” won an autographed copy of WEIT by coining the term “faitheist.” I have had some correspondence with him, and learned that one of his avocations is dinosaurs. He has an artistic bent, too, and has built models of dinos for the Children’s Museum in London, Ontario. I thought I’d post, with his permission, some photos of his latest project, especially because it includes a cat.

First the cat, who is used as a scale for Bruce’s modelling. As he tells it:

Amber has been a part of our family since the summer of 2001. We think she is about ten years old. She was dumped with her litter of kittens in my mother-in-law’s neighbourhood. She started hanging around people’s homes; people started to feed her. Her kittens were caught and homes were found for all of them through a local organization called Animalert. Mom, however eluded capture, for a while at least. Then one of the neighbours phoned Animal Care and Control, who snagged her using a noose-like device. Unlike Animalert, ACC euthanizes unclaimed animals after two weeks. So my wife and I got over there as quickly as we could to pick her up and have her put into Animalert’s system. They gave her a checkup and spayed her (apparently she was pregnant again; the Animalert people told us that if Animal Care and Control had known this they might have euthanized her right away). We agreed to foster her on a temporary basis as we already had an elderly cat (C.G. for Curious George. She died the following February at age 17). Amber had other ideas. She worked her way into our hearts and “temporary” has turned into eight years. When she is not using her talents as a geophysical standard measurement she is the furry head of our household.

AmberFig. 1. Amber

Bruce describes his latest project, which he’s been pursuing since March (you can find his ongoing posts about the project here. (Have a look; it’s an amazingly intricate operation.)

My aim is to make an accurate, poseable 1/10 scale Tyrannosaurus rex skeleton out of cheap, safe and simple materials (cardboard, wire, wood, papier mache) using simple tools and techniques. I’m using FMNH PR2081, the specimen known as “Sue”, which is part of the collection of Chicago’s Field Museum of Natual History, as my prototype. I’m going to be using Sue’s dimensions and proportions to size up my rex. The Journal of Vertebrate Paleontology’s Memoir on T.rex osteology by Christopher Brochu is my main source of information, with details from other specimens used as needed to fill in any gaps.

Amber plus dinpFig. 2. Current state of model, with Amber as scale

dino skulleFig. 3. Foundation of dino skull.

Tail vertebraent

Fig. 4. Tail vertebrae

hindlimbs

Figure 5. Hindlimb bones. Femur, tibia and fibula of papier mache, smaller bones of cardboard, tissue, glue, and acrylic paint

Bruce and SueFig. 6. His name is Bruce (and hers is Sue)

Poison dart frogs: poison, yes; dart, not so much

August 21, 2009 • 10:07 pm

by Greg Mayer

The brightly colored, poisonous frogs of the family Dendrobatidae are usually called poison dart frogs, but the name is a bit of a misnomer. While they do have toxic alkaloids in their skins, only three species are definitely known to be used for poisoning blowgun darts– Phyllobates aurotaenia, Phyllobates bicolor, and Phyllobates terribilis— all by the Noanama and Embera Choco Indians of western Colombia. The most toxic of these, and the most toxic of all dendrobatids, is the very bright yellow, and appropriately named, Phyllobates terribilis.

PhyllobatesterribilisWilfriedBerns
Phyllobates terribilis, photo by Wilfried Berns, via Wikipedia

The foremost students of these frogs have been Chuck Myers of the American Museum of Natural History, and his colleague John Daly. During a visit to the Museum some years ago, Chuck kindly showed me the terribilis he kept in his office, but I did not take any pictures, hence the Wiki photo. Their studies have shown that there is considerable individual, geographic, and interspecific variation in the poisons present in the frogs, and that individual frogs may contain multiple toxic compounds. Some of this variation results from the fact that the frogs obtain the alkaloids, at least in part, by uptake from arthropod prey.

The American Museum has made all the back issues of its scientific publications available as pdf’s, and many of  Myers and Daly’s papers, including quality color plates, are available there.  I would recommend

1976. Preliminary evaluation of skin toxins and vocalizations in taxonomic and evolutionary studies of poison-dart frogs (Dendrobatidae). Bulletin of the AMNH 157:175-262;

1978. A dangerously toxic new frog (Phyllobates) used by Emberá Indians of western Colombia, with discussion of blowgun fabrication and dart poisoning. Bulletin of the AMNH 161:309-365 (with Borys Malkin);

1995. Discovery of the Costa Rican poison frog Dendrobates granuliferus in sympatry with Dendrobates pumilio, and comments on taxonomic use of skin alkaloids. AM Novitates 3144:1-21 (with H.M. Garrafo, A. Wisnieski, and J.F. Cover).

Rational exuberance

August 21, 2009 • 11:40 am

by Greg Mayer

Continuing with the frog theme, here are two representatives of Dendrobates pumilio, the strawberry poison dart frog, from Costa Rica.

Dendrobates pumilio from Estacion Biologica La Suerte, Costa Rica
Dendrobates pumilio from Estacion Biologica La Suerte, Costa Rica
Dendrobates pumilio from Estacion Biologica El Zota, Costa Rica.
Dendrobates pumilio from Estacion Biologica El Zota, Costa Rica.

As the word “poison” in their vernacular name indicates, these frogs are toxic, and their bright coloration is aposematic: it advertises the toxicity of the frog, and protects them from predators. They may often be seen wandering boldly about the rain forest floor in daylight. These two individuals show much of the range of color variation in the species:  red backs with more or less darker speckling, and blue on the extremities ranging from the whole limb to just a hint on the toes and vent.

In northwestern Panama, however, in the region of Bocas del Toro, there are many color morphs– yellows, blues, blacks, greens– some of which are cryptic (i.e. camouflaged), rather than aposematic. In a paper last year (abstract only), Ian Wang and Brad Shaffer of UC-Davis studied the within-species phylogeny of these color morphs, and found that apparently cryptic forms had arisen multiple times. They proposed that this convergence in coloration might be driven by selection. But they admit much more work must be done:

The dramatic level of color polymorphism in the Bocas del Toro populations of D. pumilio remains difficult to explain, especially because our phylogeographic study of color evolution indicates a complex history of color changes.

Atelopus coynei, an eponymous frog

August 20, 2009 • 1:18 am

After the post about the carnivorous plant named after David Attenborough, an alert reader asked if I’d ever had a species named after me. The answer is yes: the Ecuadorian poison arrow frog Atelopus coynei.

The hundred-odd species of the frog genus Atelopus, found in Central and South America, are called “harlequin” frogs because of their bright, parti-colored pattern, and were often used as a source of poison for the arrows of locals. They’re in the family Bufonidae, so they’re really toads.

I was actually the collector of Atelopus coynei — I grabbed the holotype in a swamp on a frogging trip to western Ecuador in the late 1970s. I was there to see the tropics and help out my best friend Ken Miyata, a fellow grad student at Harvard’s Museum of Comparative Zoology.

Ken was a polymath (do read the link): a superb natural historian and biologist, a great writer (he wrote, along with Adrian Forsyth, the volume Tropical Nature that, as Greg Mayer noted, contains my botfly story — and many engrossing tales about the tropics), a fantastic photographer, and a world-class fly fisherman. He was a wonderful friend, always full of new ideas about biology and schemes about how to find a girlfriend and how to fish while getting a Ph.D. at the same time. He had a penchant for greasy food (he taught me to make the quintessential grad-student dinner: roast chicken with rice, the latter mixed with chicken grease and mayonnaise) and was fascinated by the bizarre and outlandish aspects of life.

Ken died in a fishing accident in 1983, the victim of a fast current on Idaho’s Snake River. His life had just taken a dramatic turn for the better: he found a wonderful woman and secured his dream job with a conservation organization. To celebrate, he went out West for one more fishing trip before he started his new life in Washington, D.C. They found his body three days after he went missing, enshrouded in the fishing line that had coiled around him.

During our years at Harvard, I occasionally loaned Ken some dosh to tide him over the lean times, and he promised in return that one day he’d name a species of frog after me. And so it came to pass: my beautiful frog (chocolate brown with bright green splotches) was named Atelopus coynei in 1980*. Like me, the frog (and many species in the genus Atelopus) is on the verge of extinction.

Sadly, there are no color photos of the frog, and the one drawing I have is back in Chicago; but you can read about the frog in Spanish here, and there is a brief Wikispecies entry.

Umweltbewusste-Suchmaschine-Forestle_medium

Fig. 1. One of Ken’s many frog photos

GPS13

Fig. 2. Tropical Nature, by A. Forsyth and K. Miyata. Still in print, and still one of the best introductions to tropical biology

________________

*Miyata, K. 1980. A new species of Atelopus (Anura: Bufonidae) from the cloud forests of northwestern Ecuador. Breviora. 458:1–11.

Ghostwriting scientific papers, ctd.

August 19, 2009 • 7:46 am

by Greg Mayer

In a follow up to her article on ghostwriting of medical papers by pharamaceutical companies (which I noted previously), Natasha Singer reports in today’s New York Times that a key senator is looking to halt the practice.

Senator Charles E. Grassley, an Iowa Republican who has led a long-running investigation of conflicts of interest in medicine, is starting to put pressure on the National Institutes of Health to crack down on the practice.

That is significant because the N.I.H., a federal agency in Bethesda, Md., underwrites much of the country’s medical research. Many of the nation’s top doctors depend on federal grants to support their work, and attaching fresh conditions to those grants could be a powerful lever for enforcing new ethical guidelines on the universities.

The shocking practice is to hire writers to craft papers favorable to the pharmaceutical company, and then have an academic physician’s name appear as the author of the paper when submitted to a medical journal. Although this seems bizarre to a biologist, a professor at the medical school at the flagship campus of my own university is quoted by Singer as saying, “This happens all the time.” (The quoted professor did not engage in the practice.)