Friend of the blog (and former contributor) Devin Drown is wrapping up his first year on the faculty of the University of Alaska Fairbanks, where he’s been teaching the Principles of Evolution course. As a final assignment, Devin’s students are contributing posts to a class blog, Evolution, Naturally — and the first couple are great!
Margaret Oliver digs into the phylogenetic data used to support the renaming of a genus of desert-adapted, clonally reproducing ferns — after Lady Gaga. It turns out that the singer’s stage name is literally encoded in the DNA sequence that helps differentiate the new genus from its closest relatives, as Oliver illustrates in the best. Phylogeny. Figure. Ever.
Meanwhile, Alexandria Wenninger explains how some species of ants steal larvae from other ant colonies and raise them as workers — and how entomologists are discovering that those kidnapped workers can resist this unasked-for reassignment.
However, there is a growing body of evidence suggesting that the [captured workers] are not always so oblivious to their origins, as researchers observe more and more situations of what they are calling “slave (host) rebellion”. Czechowski and Godzinska, in their recent review article, “Enslaved ants: not as helpless as they were thought to be”, identify four types of rebelling behaviors, which range from aggressive acts by individual ants to a collective uprising against the parasites.
Phylogenetics has never been this much fun. Seriously. (Screenshot: Evolution Lab)
NOVA, the flagship science program on U.S. Public Television, has just launched a new Evolution Lab website, which is chocked full of great information about the history of life on Earth, and how we study it. But my favorite thing has got to be the accompanying online game, which asks you to assemble organisms into evolutionary trees based on their traits and even their DNA sequences — it’s slick and pretty and it guides you into the logic of evolutionary relationships without explaining them point-by-point, unless you want that. I’ll be keeping this in mind for the next time I teach a basic class in phylogenetics.
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.
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.
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.
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.
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!