Why Evolution is True is a blog written by Jerry Coyne, centered on evolution and biology but also dealing with diverse topics like politics, culture, and cats.
H is for Hawk, a new memoir by Helen Macdonald, came to my attention through a hugely favorable review in yesterday’s New York Times. Although it hasn’t quite been released in the U.S.—it comes out on March 3, published by Grove Press, but has been out in England for a while—it’s already #39 on Amazon, has received starred reviews by Kirkus and Booklist, and is destined to be a big bestseller. The good thing is that it’s largely about natural history: a woman who, traumatized by her father’s sudden death, finds respite in training a goshawk to hunt. From the Times review:
Helen Macdonald’s beautiful and nearly feral book, “H Is for Hawk,” her first published in the United States, reminds us that excellent nature writing can lay bare some of the intimacies of the wild world as well. Her book is so good that, at times, it hurt me to read it. It draws blood, in ways that seem curative.
Ms. Macdonald is British, and when we meet her in this memoir, she is in her 30s, with “no partner, no children, no home.” Her fellowship at the University of Cambridge is coming to an end. When her father, a newspaper photographer, dies suddenly on a London street, it steals the floor from beneath her.
She has been obsessed with birds of prey since she was a girl, and is an experienced falconer. In her grief, to escape into something, she begins to train one of nature’s most vicious predators, a goshawk. She unplugs her telephone. She tells her friends to leave her alone.
Every review I’ve seen has been very favorable. Here’s one from the Guardian
Macdonald struggled to put her complicated life back together but two parts of her unusual restorative therapy were the acquisition of a goshawk called Mabel and a year-long plan to tame and train her to hunt. H is for Hawk is at once a misery memoir, as the author grapples with the grieving process, and a falconer’s diary about the hard-won trust between hawk and human. Yet she also splices into her narrative a biographical account of a literary hero and fellow austringer (the title for one who trains goshawks): TH White.
You can read more about this book for yourself, and can even preview it by reading select pages on Amazon, but I know that I, for one, will be reading it.
Surprisingly, the Times doesn’t mention an obvious comparison for Macdonald’s work: the absolutely wonderful book The Peregrineby J. A. Baker. It recounts a year’s observation of peregrine falcons in Essex, and contains some of the most beautiful nature writing I’ve ever read. If you have a birder, an outdoor person, a nature lover, or simply a lover of good prose in your life, you could do worse than to give them Baker’s book. I wrote a lot about it during “Peregrine Week” nearly five years ago, so you can read some selections at the previous link. Baker, like Macdonald, seems to have suffered some trauma that led him to the birds, but it isn’t made explicit in his book.
Here’s the author of H is for Hawk:
Helen Macdonald (Photo by Marzena Porgozaly, NYT)
And here is a northern goshawk (Accipiter gentilis), an individual similar to the one Macdonald Trained:
A northern goshawk. Photograph: Bernd Zoller/Getty Images/Imagebroker RF
Reader Scott from Australia sent me this short video of two of his religious countrymen (countrypeople?) discussing whether God wants them to have sex. The answer was a resounding “yes,” and when I was told this was a video designed by Anglicans to be part of the religious curriculum in public schools, I thought it was a joke. But it isn’t. As Scott noted, “it is by a group called Youth Works run by the Sydney Anglicans.”
Apparently, a secular group called “Fairness in Religions in School” (FIRIS) nabbed the video and slapped it on YouTube before the Anglicans could take it off their site. As you may know, in some Australian states “special religious instruction” is allowed in the public schools, and it’s supposed to teach about the characteristics of faith rather than promote a particular faith. FIRIS fights this because it has indeed been used to proselytize kids. (See here for one example.) I understand that kids can also opt out of this instruction, though readers from Oz might educate us in the comments.
At any rate, it puzzles me that a country as secular as Australia still has government-sponsored religious education in its public schools. But maybe it’s not so bad if it teaches stuff like this!:
It’s hilarious! Some quotes:
“God actually invented [sex], and so he thinks it’s good. . . These physical parts that [God] has created are different, but they go perfectly together. . . And not only that, but they come together in a way that’s actually pleasurable for us, and God made it that way so that we’d actually enjoy having sex together.”
It goes on, and Steve and Naomi Chong (I think they’re married, not brother and sister) later add that God designed sex to be enjoyed in marriage, and it’s physically and emotionally “damaging” if that plan is obviated, but I doubt that kids will pay attention to that part!
And you just know that after the cameras are turned off, these two went for each other like a pair of lustfully crazed weasels. . .
Many thanks to the readers who have been sending me nice photos. I’m sequestering all that I don’t use, and most will eventually appear. I’ll try to let readers know when their photos are up.
First, two arthropods from reader Gaurav:
This is a longhorn beetle, which has been identified to me as Lepturinae, probably Anthophylax. You can see it has a pseudoscorpion riding along as a phoretic parasite.
Diana MacPherson sent three photos:
Here are some of today’s pensive birds: a tree sparrow (I like the sparrow’s grey face), a junco and a female cardinal (who was much less nervous than her bright red male companion).
Female cardinal (Cardinalis cardinalis) in Weigela
Tree Sparrow (Spizella arborea) Sitting on Rain Gauge
Reader Robert Seidel sent some pictures of The Birds:
These were taken in Eckernförde, Northern Germany, on last Sunday, February 15. Each black dot is a perching rook (Corvus frugilegus). They gather at dusk to spent the night in those trees. Reminds me of some film I’ve seen once, but I can’t quite remember which one 😉
Today’s animated Google doodle (click on screenshot below to see it go) celebrates the beginning of the lunar new year with a cute sheep whose head-butting sets off fireworks that spell “Google.”
In China it’s the Year of the Sheep, ergo the ram, but some say it’s the year of the goat. This has led to consternation, according to the New York Times:
For English speakers, it is a can of worms.
“Few ordinary Chinese are troubled by the sheep-goat distinction,” Xinhua, China’s main state-run news agency, said in its report on the debate. “However, the ambiguity has whipped up discussion in the West.”
The reason is that the word for the eighth animal in the Chinese zodiac’s 12-year cycle of creatures, yang in Mandarin, does not make the distinction found in English between goats and sheep and other members of the Caprinae subfamily. Without further qualifiers, yang might mean any such hoofed animal that eats grass and bleats. And so Chinese news outlets have butted heads for days on what to call this year in English, recruiting experts to pass judgment.
. . . The prevalent theory goes that because Han Chinese culture developed in regions where herders and goats prevailed, the zodiac talisman must be a goat. The animal is indeed common in traditional New Year art. But sheep have their proponents, and they have become more common in cutesy cartoonish decorations for the celebrations.
Zhao Shu, a folklore expert at the Beijing Institute of Culture and History, said in a telephone interview that the debate was silly. The creature in question arose as a general symbol of plenitude and good fortune, partly because the Chinese character yang shares roots with the one for auspiciousness, he said.
You should know your animal, and Professor Ceiling Cat has kindly found this chart to tell you what your sign is (note that it’s goat, not sheep):
If you want to see how your birth year and iconic animal affects your personality, go hereand click on your animal.
The Ox is a person who will often find themselves in the same place or situation for longer periods than others. Whether it is in a relationship, a job, or just a phase of their life, the Ox is built to both endure and succeed. Part of this is that they will tend to favor those things that they are already familiar with. This allows them to make the most of what they can do, and in many ways to eliminate the chaos from their own world that seems to control so many others.
As someone who holds out for what they want, the Ox is also someone for whom discipline is second nature. They can maintain a level of work and a state of mind far beyond many of their peers, both in their personal and professional lives. It can be hard, however, to endure sudden changes in their life, at least for the first few days. As the Ox slowly refocuses their mind, though, they will soon return to a more stable and happy state. It simply takes them a little longer than others to figure out what is the best path for them. Though once they do, they are strong and determined.
Spot on! I’m also told that I’m compatible with Rats, Tigers, and Snakes, but not with Rabbits, Sheep, or Pigs. The site also tells you about your romances, your interpersonal relationships, and what kind of year you’re gonna have. You can’t resist clicking on it, can you? Feel free to describe in the comments its accuracy with respect to you.
Well, I see by my weather app that it’s a balmy -6ºF outside (-21ºC), but that’s still one degree higher than the all-time record low temperature for this date, set in 1936. UPDATE: It’s now -7ºF, so we’ve tied the record, though the news reports say that, with the wind, it feels like -21ºF (-30º C). I’m about to go out in it, and have donned extra layers.
Nevertheless, the relentless cold has led officials to close all public schools in Chicago today, though of course the University of Chicago will remain open. (We’re not weenies!) Meanwhile in Dobrzyn, the weather is balmier and Hili is spending some time outside. But she still gets restive at night, and becomes a bit mischievous:
Hili: Is this lamp anchored securely?
A: You’d better not try it.
Hili: Could you stand under the lamp and be our safety net?
When I asked how a chubby Hili could get up there, Malgorazata replied, “Hili is as agile as she was when she was slimmer. She jumps on the small cupboard which is on the veranda, from there she jumps on the hanging wicker shelf and up to the beam under the roof. She comes down the same way.”
In Polish:
Hili: Czy ta lampa jest porządnie zawieszona?
Ja: Lepiej nie sprawdzaj.
Hili: Czy możesz stanąć pod tą lampą i nas asekurować?
The Saturniidae is a large family of moths (ca. 2300 species), and is also a family of large moths, including some of the world’s biggest and most beautiful.
Here’s one of them: the luna moth (Actias luna); this one’s a female. Notice two features of this insect: the long “tails” on the rear wing, and the eyespots on the same wings. There’s also one feature you can’t see: like mayflies, the adults hatch without mouths, so they can’t eat. They live only to mate and produce the next generation, and they die within a week after breaking out of the cocoon.
It’s been known for a while (from experiments) that these eyespots serve to distract predators, mostly birds who peck at them and, while possibly inflicting damage on the wing, also avoid pecking at the vital head and thorax, giving the pecked moth a chance to escape. There’s an obvious selective advantage in that. (In some lepidopterans the eyespots may also frighten away predators by resembling the eyes of scary birds like owls.)
But what about those long tails? A new paper in Proceedings of the National Academy of Sciences (US) by Jesse Barber and colleagues (reference below; free abstract and pdf) suggests that they help distract predatory bats. Like most moths, saturniids are largely nocturnal, and so they’re subject to predation by animals that can’t see very well: bats! Bats hunt by sonar, and the authors tested the hypothesis that the moths’ “tails”, which spin and wiggle as they fly, are attractive to bats, who attack them and leave the vital body alone. They suspected that the tails had evolved to help the moths escape predation.
In short, the authors put luna moths together with big brown bats (Eptesicus fuscus) in a darkened and soundproofed room, and filmed what happened with infrared cameras (and listened with ultrasensitive microphones). They used eight bats and 162 luna moths, as well as “control” moths. In each trial, a bat was put in the room with one intact luna moth, one luna moth with its tail “ablated” (science jargon for “cut off”), as well as a control pyralid moth. For convience in filming, moths were tethered to the ceiling with a length of monofilament line. Luna moths and big brown bats don’t live in the same place in nature, so the bats were hunting moths that they’d never before “seen.”
Here are the results from the paper, showing that the tails made a very big difference in the probability of being captured (you can also see five movies on the site showing the bats’ hunting behavior). My emphasis in the following:
Bats captured 34.5% (number of moths presented; n = 87) of tailed luna moths, and 81.3% (n = 75) of moths without tails were caught—a 46.8% survival advantage for hindwing tails (Fig. 1). Mixed-effects logistic regression revealed a moth without tails is 8.7 times [confidence interval (CI) = 2.1–35.3] more likely to be captured than a moth with tails. During each foraging session, we presented a bat with one intact luna moth, one luna moth with its tails ablated, and 1–2 pyralid moths as controls. Control moths were captured 97.5% (n = 136) of the time.
What happened is that bats aimed at the intact moths’ tails about half of the time, and when they did so they were only 4% successful at catching the moth. But when they aimed at the ablated moths’ bodies, they were as successful at killing it as they were when targeting the bodies of intact moths (72%).
While these results are strongly suggestive that the tails might have evolved to help elude bats, there are some caveats.
1. Maybe the tailed moths were harder to catch simply because they were bigger than the snipped moths. Big brown bats catch moths by enfolding them in a wing, and then bringing the tail up to scoop the moth into the mouth. Maybe the tailed moths are simply harder to catch that way, and so the tails evolved not to distract bats, but to make the moths harder to scoop up. To test that, the authors also presented the bats with saturniid moths that don’t have tails (Antheraea polyphemus), but are even bigger in body+ wing area than are luna moths. These controls were indeed caught less often than snipped luna moths, suggesting that bigger surface area does matter, but the effect wasn’t big enough to explain the difference between snipped and intact moths. However, the probability that the tails had an effect beyond just increasing size wasn’t impressive: the p value (probability that tails didn’t have an real effect but one that appeared by chance) was marginally significant—less than 5%. That’s significant statistically, but not terribly impressive.
2. Maybe there are other selective pressures that explain tails in moths. One suggestion is that they help the moths fly better. The authors analyzed flight behavior in snipped versus unsnipped moths and found that only the frequency of wingbeat changed—from 10 to 11 Hz (whatever that is)—but they claim that no feature of flight changed that could help the moth evade predators,
Well, okay, that’s something. What about sexual selection, though? Could the long tails be attractive to females, males, or both? The authors consider this unlikely because males and females have similar sized tails (sexually selected traits often differ in size or elaboration between the sexes, with males usually showing the larger or more elaborate trait). Further, the moths apparently mate at night, and don’t use visual cues for mating. In some species of moths, though, males do have longer tails than females, but the authors say that this might be due not to sexual selection but predation: males spend more time flying than do females, for they’re looking for the females, and thus are under more selection to avoid predation. That sounds a bit like special pleading.
All in all, though, I think the authors have a reasonable case that the tails deter bat predation, though it would be nice to do the experiment with other species of tailed moths. Further, the low significance of the results, especially in tests of the body-size hypothesis, is a bit worrisome. Still, the results are better than simply looking at the moths and making up an adaptive story without testing it! This was, after all, a very hard experiment to do.
Finally, the authors wanted to know how many time long tails in moths have evolved independently. They made a phylogeny (family tree) of representatives from 7 moth families using five nuclear genes and one mitochondrial gene, and then superimposed on that the tail sizes of the moths. The phylogenetic tree + tail size diagram shown below clearly indicates that long tails evolved independently in this group at least four times (the gray shaded bits of the tree). I’ve put the original figure caption below so you can see what the colors mean:
ML molecular phylogeny of saturniid moths showing multiple independent origins of hindwing tails. Filled black circles indicate origin of tails. Open circles indicate losses. Branch colors indicate length of hindwing tail from absent (blue) to >50 mm (red), based on Phytools continuous character evolution analyses. Numbers by branches are bootstrap values. Gray shading denotes groups that have spatulate tails and contain species with tail lengths greater than 37.5 mm (the average for A. luna, n = 10). The images of saturniid moths used in these experiments are labeled: (A) A. luna and (B) A. polypheumus. Bold type and asterisks denote species that have tails longer than 37.5 mm. In combination with our bat–moth interaction data, this phylogeny suggests that tails serving a clear anti-bat function have evolved 4 times. Three additional origins of very short tails, of uncertain function, are also apparent.
The classic bromide of scientific conclusions holds here: “More work needs to be done.” Nevertheless, we know a bit more than we did before, and this result may lead others to look for additional and non-obvious antipredator strategies of lepidopterans. As we always say in the Darwin game: “Evolution is cleverer than you are.”
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Barber, J. R., B. C. Leavell, A. L. Keener, J. W. Breinholt, B. A. Chadwell, C. J. W. McClure, G. M. Hill, and A. Y. Kawahara. 2015 Moth tails divert bat attack: Evolution of acoustic deflection. Proc. Nat. Acad. Sci. USA, early edition, 10.1073/pnas.1421926112
Alessandro Volta, born on this day in 1745, is credited as inventing the battery, and of course gave his name to the unit of electrical potential. The Google doodle today, which lights up and flashes (click on screenshot below to see it) honors his 270th birthday.
Over at Google, the artist, Mark Holmes, explains how he researched and then made the doodle, rejecting several designs. But in a Guardian piece called “Alessandro Volta, a welcome but misleading Google doodle“, Charlotte Connelly carps that the doodle falsely implies that Volta invented the light bulb. (To be fair, she spends most of the piece recounting Volta’s story.) But Jebus, if you click on the doodle, which you should always do, it takes you to a whole pile of information on Volta. Don’t people want to know more than gawk at the lights?
