July 29, 2012 § Leave a comment
He must have had some really high insulin levels when he was growing up!
No, seriously. That’s what they say. They, in this case, being a quintet of biologists from the University of Montana (among other places), who’ve come out with a new study detailing the likely molecular underpinnings of the extravagantly long, wildly varied horn of the male Japanese rhinoceros beetle.
Yep, there it is: the giant branch coming off his face. It’s a terribly useful tool for a beetle, perfect for knocking male competitors out of the way during a fight for a lady beetles—which naturally makes bigger all the better. Unfortunately for the poorly endowed, the size of the horn is entirely determined by the growing conditions the beetle endured as a grub. Good food and low stress make for a huge, manly horn that can, in the best of times, grow up to nearly the length of the beetle. Poor nutrition, infection, or bad genes leads to a sad little stump that won’t be much use against a bigger male.
Now, the operating factor in all of this is insulin and the insulin-like growth factor (IGF) system. That’s also the molecular key that determines how big the beetle becomes as a whole. You’ve actually got the same thing; it’s what made you grow while you were on the up and up, and ditto me, my cat, fish, reptiles, crustaceans, and so on. More food leads to more insulin, which powers the engine that leads to more growth, and vice versa. It’s one of the oldest, most conserved systems in the evolutionary playbook. « Read the rest of this entry »
July 23, 2012 § Leave a comment
Stick a dog in a pasture full of sheep, you’re going to have yourself a full-on every-ovine-for-itself stampede to the center of the herd—because each and every sheep on that field wants to make sure his edible neighbor gets eaten first. There will be no heroics, and at long last, say researchers from the University of London, they’ve got the numbers to prove it.
The study, which appears online today in Current Biology, set out to quantify what’s known as the Selfish Herd hypothesis: animals that stick together do so to reduce their individual odds of being killed (Ha ha! Won’t eat me if it gets Bob first!). Sheep do it, in theory, as do crabs, seals, insects, fish, and just about every other animal that typically flocks. In this case, the researchers took 46 sheep, one Australian Kelpie working dog, and 47 GPS trackers—one per animal—then set the dog to work herding sheep through a gate in three trials over three different days. In each case, according to the second-by-second data collected from the devices, as soon as the dog came within roughly 70 meters of the group, the sheep clustered together, forming a tight herd in their haste to get not just next to their fellow sheep, but into the dead center of the group, which itself collectively and simultaneously shifted away from the threat.
Wait, what’s that you say? You’re not shocked? This was common knowledge? Correct, says Andrew King, lead author of the study. « Read the rest of this entry »