Monarch butterflies aren’t quite extinct yet!

The New York Times reports that monarch butterflies migrating from North America to central Mexico appear to be doing better than last year, when the over-wintering colony occupied just 1.7 acres. This year’s survey finds the butterflies have filled 2.8 acres, which seems like a solid improvement until you consider that the peak colony size, since record-keeping started, was 44.5 acres.

(Incidentally, 44.5 acres is more than 40 American football fields of forest covered with roosting monarch butterflies.)

The monarchs that migrate to Mexico aren’t the only population — there’s another migratory route on the U.S. Pacific coast, and there are non-migratory populations in Florida, Hawaii, and even New Zealand. But the Mexico overwintering site represents what used to be the single largest monarch population, butterflies that spend summer across most of North America east of the Rocky Mountains. Logging in Mexico and the loss of summer habitat to farming in the Midwest has been hitting the butterflies hard for years, and while this rebound is encouraging, it might still make sense to put the monarch on the Endangered Species List, as the U.S. Fish and Wildlife Service is considering.

Under selection, an endangered species runs low on evolutionary “fuel”

Atlapetes pallidiceps

A pale-headed brushfinch, Atlapetes pallidiceps. (Wikimedia Commons:Aves y Conservación/NBII Image Gallery)

The pale-headed brushfinch, Atlapetes pallidiceps, is a conservation success story, or at least the first chapter of one. The birds were thought to be extinct, until a 1998 survey [PDF] of Ecuador’s Yunguilla Valley found four nesting pairs, and observed them foraging for insects and fruit. Following that rediscovery, the Fundacion Jocotoco secured a reserve encompassing the brush finches’ known territory, and took steps to control brood-parasitic cowbirds that were threatening them. Now, the population is five times bigger, with as many as 200 of the birds living in the reserve.

Have the brush finches’ rebounded enough to secure their population for the future? Populations that decline so precipitously can lose genetic variation, and may not regain it even if their numbers increase again. With reduced genetic variation, species that have undergone such a “population bottleneck” event may be unable to respond to natural selection imposed by disease or changing environments.

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Purple martins, helped and harmed by humans

My grandfather, a farmer in rural Virginia, was never much worried about saving endangered species or stopping climate change, or any environmental issue that didn’t directly impact next year’s soybean harvest. But as long as I can remember, he maintained a tiny apartment house on a pole in his back yard — just for purple martins.

Martins are glossy, deep-purple swallows that nest in big colonies. Originally, they used cavities in dead tree trunks and cliffs, but in eastern North America they’re now entirely dependent on human-made birdhouses like my grandfather’s. In a great video, Adam Cole of NPR’s Skunk Bear, talks to some martin landlords, discusses some of the challenges the birds face in modern times, and goes on an expedition to find one of the roosts where they gather in huge flocks before migrating to South America for the winter.

Bringing back the “king” of American forests

The American chestnut used to be one of the most common trees in North American hardwood forests, providing enormous crops of nuts that supported birds and other wildlife, and a source of robust, rot-resistant lumber for human use. But American chestnuts were nearly wiped out by the introduction of a virulent chestnut blight from Asia.

But now, after years of selective breeding and some careful genetic engineering, biologists at the State University of New York and the American Chestnut Foundation have produced blight-resistant chestnuts and they’re getting ready to start restoring the population with a crowd-funding campaign. If American chestnuts couldn’t evolve to cope with blight on their own, they may be one of the first species to get an evolutionary helping hand from humans.

“Dance your Ph.D.” winner gets up in the air to explain life underground

The winner of this year’s “Dance Your Ph.D.” contest, Uma Nagendra, studies fungi that infect the roots of pine seedlings—seedlings that grow too close to an adult tree, such as their own parent, can be at higher risk of fungal disease transmitted from the adult’s roots. Nagendra depicts those underground interactions, and what happens when a tornado upends them, in a choreographed trapeze performance. Cool!

Tracing the start of monarch butterflies’ epic journey, in their genes

Monarch butterflies (Danaus plexippus) are among the most widely recognized wild creatures in North America. Their distinctive orange-and-black wings, which warn predators that the butterflies are chock full of toxins from the milkweed they eat, make them easily spotted in backyard flower beds. They’re also known for a massive annual migration, flying thousands of miles between wintering colonies in central Mexico and summer sites across the United States and Canada. More recently, it’s been discovered that female monarchs infected by parasites respond by laying their eggs on food plants that can prevent the parasite from infecting their offspring.

Monarchs are also one of the more visible victims of the massive changes humans have made to the world around us. Increased conversion of farmland to corn production has reduced the supply of milkweed, the butterflies’ only food plant, across much of the Midwest. It’s gotten so bad the number of monarchs making the annual migration back to Mexico hit a record low last year, and while things were better in 2014, a nationwide campaign to encourage planting of milkweed in home gardens is only beginning.

For all our familiarity with monarchs, we’ve known remarkably little about their evolutionary history. That’s changing rapidly now, as evidenced by a paper published last month in the journal Nature, which uses a big new genetic dataset to trace the origins of some of the monarch’s most distinctive features.

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Celebrating Alfred Russel Wallace with … a symposium of only straight white men?


A sample of Alfred Russel Wallace’s butterfly collection, which is a lot more colorful than the panel of speakers UCLA has chosen to celebrate his legacy. (Natural History Museum, London)

Update, 31 October: Elizabeth Long asked me to post the following statement about developments since the letter was sent last week:

Perhaps rather naively, I didn’t anticipate the amount of publicity our letter regarding the upcoming public Wallace Centennial Celebration would generate. I had hoped to start a discussion about the issues surrounding diversity and safety in STEM that were raised, and I’m glad to say that this has happened. I have had several very thoughtful and productive conversations with the event organizers and I can confidently and emphatically say that issues surrounding diversity and equality are very important to them. In various ways they’ve each shown this commitment, throughout their careers, through concrete actions.

I asked one of the organizers to help summarize the history of the event. Paraphrasing our discussion: In this specific case the original grant submission included women speakers (4 of 8 speakers) but for various reasons they were ultimately not able to participate. The event organizers wanted to host speakers who are not only excellent scientists and speakers but are also knowledgeable about Wallace and his legacy, which led to a narrow set of selection criteria and led to the original publicized lineup. The revised lineup includes two remarkable women, one an historian of science, and the other an evolutionary medicine specialist.

Update, 29 October: It’s been brought to my attention that the list of symposium speakers now includes Soraya de Chadarevian and Barbara Natterson-Horowitz, which suggests that the organizers are making some changes.

Update, 25 October: I’ve amended the headline of this post to better reflect, I hope, that what the letter and its signatories object to is not the inclusion of white men on the symposium panel, but the lack of inclusion of similarly accomplished folks from groups that are systematically underrepresented in science. As I note below, the panelists are highly accomplished, and appropriate for the Wallace Centennial—but the panel could include women as well without compromising the prestige or topicality of its membership.

2014 marks a century since the death of Alfred Russel Wallace, who is recognized as co-discoverer, with Charles Darwin, of evolution by natural selection. Appropriately, the University of California Los Angeles is holding a symposium of biologists and natural historians to celebrate Wallace’s life and work. Unfortunately, the panel of speakers chosen for the symposium doesn’t exactly reflect the diversity of humanity, or even humans who are biologists and natural historians. Although there are lots of very accomplished folks on the panel who will likely give interesting talks, they’re all straight (so far as I know) white men. That’s right, the Alfred Russel Wallace Centennial fails the gay bar test pretty spectacularly.

Elizabeth Long, a biologist at UCLA and the Natural History Museum of LA, has organized a group of folks to write a letter to the symposium organizers pointing this out—and, just to make it clear how unnecessary an all-male panel is, included a list of accomplished ecologists and evolutionary biologists who are not men. The letter, which I’ve co-signed, also points out that an all-male panel exacerbates problems that women already encounter in academia, and is at odds with Wallace’s legacy as a supporter of equal rights for women. But I’ll let you read the full text, which is after the jump:

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Life, um, finds a way—except when it doesn’t

This week the LA Review of Books has my review of Unnatural Selection, a nifty new book in which ecological toxicologist Emily Monosson describes how living things evolve their way around the things we humans do to try and contain them.

… the introduction of the insecticide DDT rapidly led to the evolution of resistant mosquitoes, houseflies, and, yes, bedbugs. Decades of farming with the herbicide glyphosate, better known under the brand name Roundup, have led to the evolution of resistance in dozens of weed species. One after another, Monosson ticks off cases, dividing them into chapters corresponding roughly to biological classification. She goes beyond these headline examples to describe lesser-known triumphs of “resistance evolution,” such as viruses evading human immune responses and inadequate vaccination, cancer cells overcoming chemotherapy, and fish that survive water polluted by biochemical toxins.

This hits some of the same themes as that recent review about using evolutionary biology to solve major problems in the coming century, though I might have liked it if Unnatural Selection spent a bit more time discussing the cases when life doesn’t find a way—the myriad reasons we’re in the middle of the sixth mass extinction in the history of the planet. But I highly recommend the book for the folks in your life who may not realize how personal evolutionary biology can be.

Best. Broader impact. Ever.

Like everyone with an Internet connection, earlier this month I heard a fair bit about U.S. 7th Circuit Court Judge Richard Posner’s ruling striking down bans on same-sex marriage in Indiana and Wisconsin. As Mark Joseph Stern put it at Slate, “Posner … sounds like a man who has listened to all the arguments against gay marriage, analyzed them cautiously and thoroughly, and found himself absolutely disgusted by their sophistry and rank bigotry.” Here’s a choice sample from the full opinion:

The challenged laws discriminate against a minority defined by an immutable characteristic, and the only rationale that the states put forth with any conviction—that same-sex couples and their children don’t need marriage because same-sex couples can’t produce children, intended or unintended—is so full of holes that it cannot be taken seriously.

What I hadn’t heard before is that Posner’s opinion also includes a short run-down on research about the biological basis of sexual orientation, and it has more than one familiar citation:

Although it seems paradoxical to suggest that homosexuality could have a genetic origin, given that homosexual sex is non-procreative, homosexuality may, like menopause, by reducing procreation by some members of society free them to provide child-caring assistance to their procreative relatives… There are other genetic theories of such attraction as well. See, e.g., Nathan W. Bailey and Marlene Zuk, “Same-Sex Sexual Behavior and Evolution,” forthcoming in Trends in Ecology and Evolution

That’s actually a reference to a 2009 review, which is online in PDF format—it covers the diversity of same-sex sexual behaviors across the animal kingdom. It hardly mentions Homo sapiens, but it is one of the sources I give to people who want a solid introduction to current scientific thinking about how same-sex attraction could have evolved. If you ask me, one could do a lot worse than having a paper cited in a groundbreaking legal ruling. And it’s a reminder to those of us studying the history of life in general that our work can have unexpected consequences beyond the lab.