Jewelwing damselflies (Calopteryx maculata) mating. (Flickr: Lisa Brown)
Over at Nothing in Biology Makes Sense, I’ve posted a long-overdue review of a terrific little book about naughty parts. Genitals. Junk. It’s called Nature’s Nether Regions, by evolutionary biologist and entomologist Menno Schilthuizen, and it puts the weird world of (animal) reproductive anatomy on full display, while avoiding the cliches and pitfalls into which so many popular accounts of sex and evolution fall.
The book’s subtitle What the Sex Lives of Bugs, Birds, and Beasts Tell us About Evolution, Biodiversity, and Ourselves, might be a bit ominous to a reader familiar with the many hazards of evolutionary hypothesizing about human behavior, but Schlithuizen’s chatty tour of animals’ sexual anatomy dodges them all. He does this, in large part, by devoting far more time and attention to the “evolution” and “biodiversity” than to “ourselves,” putting the rather pedestrian reproductive arrangements of Homo sapiens in their place amidst the baroque diversity of appendages, receptacles, secretions, and behaviors other animals employ to multiply their kinds.
Go read the whole review, which includes some sampling of the natural history Schilthuizen covers, and then check out the book itself.
A mountain vista in Colorado, with trees killed by pine beetles in the foreground. (Flickr: John B. Kalla)
Over at Nothing in Biology Makes Sense, I discuss a big new review article on all the ways understanding evolutionary biology will be critical for human health and development in the next hundred years:
The long list of authors, led by Scott P. Carroll and including Ford Denison, whose lab is just down the hall from my office at the University of Minnesota, explicitly connect evolutionary principles to global goals for sustainable development. These include the reduction of both “chronic lifestyle” diseases and infectious diseases, establishment of food and water security, clean energy, and maintenance of healthy ecosystems. Carroll and his coauthors divide the applications of evolution to these problems into cases where evolution is the problem, and those where evolution may offer the solution.
Over at Nothing in Biology Makes Sense, Chris Smith has been writing a series of posts digging deep into the evolutionary claims made in Nicholas Wade’s book A Troublesome Inheritance. Last week, Chris debunked the claim that human population genetics naturally sorts into “races”—this week, he’s taking on Wade’s claim that variation at a particular gene has made some human populations more prone to violence than others:
Although some studies have found genetic variants in the MAO-A promoter region that are more common in some ethnic groups than in others (Sabol et al. 1998; Widom & Brzustowicz 2006; Reti et al. 2011) it is likely that these genetic variants are not –on their own– associated with violent or impulsive behavior (Caspi et al. 2002; Widom & Brzustowicz 2006). Instead, genetic variation in the MAO-A promoter seems to make some children less able to recover from abuse and childhood trauma, and therefore more likely to act out later in life (Caspi et al. 2002; Widom & Brzustowicz 2006). Simply carrying the ‘low expression’ allele in the MAO-A promoter does not have any effect at all on impulsivity or aggression.
Chris co-teaches a class on exactly the topics covered in A Troublesome Inheritance, so I highly recommend you read the whole thing, and follow the series to its conclusion.
At the CGRI, we would like to understand first, how much genetic variation there is in the numerous pure C. sativa, C. indica, and C. ruderalis accessions and heirloom varieties. This will lead us to understand the relationships among the major lineages within the genus, the spread of Cannabis throughout the globe, and rates of historical hybridization between the named species.
For Daniela’s detailed run-down of important evolutionary questions in Cannabis, go read the whole thing.◼
At Nothing in Biology Makes Sens, Sarah Hird explains some of her own research, recently published at the journal Heredity, which documented just how “leaky” species boundaries can be in the chipmunks of western North America.
While doing a comparative phylogeography study, the Sullivan lab discovered that one particular subspecies, T. a. canicaudus, had a mitochondrial genome that was most closely related to the red-tailed chipmunk (T. ruficaudus), instead of the other yellow-pine subspecies. Additional data show that the T. a. canicaudus nuclear genome is in fact most similar to other yellow-pines – it’s just that the mitochondria is of red-tailed origin.
This week at Nothing in Biology Makes Sense! I’m discussing a new study that purports to demonstrate that three-toed sloths are in a nutritional mutualism with specialized moths, fueled by algae and poop:
Sloths’ coarse, shaggy fur accumulates its own little microcosm of living passengers. (If you move that slowly in a tropical forest canopy, you’re going to get some hop-ons.) Among these are an assortment of algae, and moths in the genus Cryptoses. It’s been known for a long time that Cryptoses moths lay their eggs in sloth dung, and that their larvae eat it.
To find out why it isn’t completely crazy to think that these poop-eating moths might be helpful to sloths, go read the whole thing.◼
Over at Nothing in Biology Makes Sense!, Amy Dapper discusses a new study of brood parasites, birds that lay their eggs in the nests of other bird species, letting those adoptive hosts take on the costs of raising the brood parasites’ chicks. This sounds like a bad deal for the host species, but in at least one case, it turns out that a brood parasite chick can be a boon to its adoptive nest-mates:
Canestrari et al. (2014) focused on the great spotted cuckoo (Clamator glandarius) and their host, carrion crows (Corvus corone corone). They studied the success rate of nests with and without brood parasitism and found that carrion crow nests that contained parasitic cuckoo nestlings were actually more likely to be successful (i.e. fledge at least one crow nestling). How could this be?
The life sciences building at the University of Idaho. Photo by jby.
Over at Nothing in Biology Makes Sense! Noah Reid tackles the question that was left hanging in my recent article about a six-day creationist teaching introductory microbiology at the University of Idaho: how a person with such questionable credentials could have been hired in the first place. Noah argues that it’s a symptom of the poor treatment of adjunct faculty in American higher education.
These faculty are hired on a course by course, semester by semester basis. They receive no benefits and don’t have a shred of job security. By some estimates an average “full-time” adjunct faculty member teaching 8 courses a year (3 each semester and 2 in the summer, perhaps?) would make less than $30,000 a year and it’s thought that adjunct faculty are now doing 70% of the teaching at higher education institutions in the US.
… In response to this, I want to use a recent post at this blog to highlight a slightly less well covered aspect of the issue and the other side of that coin: when you offer shitty compensation, you might just get shitty employees.
A cane toad, living in an evolutionary “Olympic village”? Photo by tubagooba.
This week at Nothing in Biology Makes Sense!, Devin Drown explains the population dynamics that crop up near the edge of a species’s geographic range:
One famous example of this phenomenon is found among invasive cane toads (Rinella marina) in Australia. In 2006, Phillips et al found that the toads at the leading edge of the expansion had longer legs making them primary candidates for high dispersal capabilities. Later, Lindstrom et al (2013) found (via radio collar measurements) that those toads at the front of the range were more likely to disperse than those at the encamped within the population.
To find out why biologists have compared life on the range edge to living in the athletes’ dormitory at the Olympics, go the whole thing.◼