It seemed like such a simple story. Some birds lay their eggs in the nests of other birds of their own species. This practice, known as brood parasitism, foists the burden of parenthood onto other birds, who unwittingly devote their energies to raising someone else’s chicks. The exploiter wins; the victim loses.
This story is wrong, at least for eider ducks. Ralph Tiedemann from the University of Potsdam has shown that among these birds, brood parasites are most likely to target their own relatives, especially older ones who lay smaller clutches of eggs themselves. They aren’t putting their babies on the doorsteps of random strangers; they’re offering them to Grandma. The ‘victim’ isn’t really a victim; she’s the family babysitter.
The common wisdom is that your fingers wrinkle when they’re wet because they absorb water. But Mark Changizi thinks there’s more to it than that. According to him, pruney fingers are an adaptation to help humans, and probably other primates, get a better grip during wet conditions. They act like the rain treads on tyres. Mark lays out his hypothesis in a wonderful paper that I wrote up as a news story for Nature News.
Here’s the start; click through for the whole thing.
The wrinkles that develop on wet fingers could be an adaptation to give us better grip in slippery conditions, the latest theory suggests.
The hypothesis, from Mark Changizi, an evolutionary neurobiologist at 2AI Labs in Boise, Idaho, and his colleagues goes against the common belief that fingers turn prune-like simply because they absorb water.
Changizi thinks that the wrinkles act like rain treads on tyres. They create channels that allow water to drain away as we press our fingertips on to wet surfaces. This allows the fingers to make greater contact with a wet surface, giving them a better grip.
Scientists have known since the mid-1930s that water wrinkles do not form if the nerves in a finger are severed, implying that they are controlled by the nervous system.
“I stumbled upon these nearly century-old papers and they immediately suggested to me that pruney fingers are functional,” says Changizi. “I discussed the mystery with my student Romann Weber, who said, ‘Could they be rain treads?’ ‘Brilliant!’ was my reply.”
Reference: Changizi, Weber, Kotecha, & Palazzo. Brain Behav. Evol. http://dx.doi.org/10.1159/000328223 (2011).
I’ve just spoken at the opening plenary of the second day of the World Conference of Science Journalists at Doha, Qatar. It’s a panel called “Am I a science journalist?”with myself, my fellow Discover blogger Chris Mooney, Mo Costandi, Homayoun Kheyri, and Cristine Russell.
Here’s the description of the panel:
In the evolving world of science communication, how do we define a science journalist? This panel will discuss whether the venerable word “journalist” can or should be applied to some, all, or none of the new generation of science bloggers and educators who are remaking the field.
And this is what I said:
The cleaner fish Laborides dimidiatus is cross between a janitor and a medic. It runs special “cleaning stations”, which other fish and ocean animals visit for a regular scrub. The cleaners remove parasites from their clients, even swimming into the open jaws of predators like moray eels and groupers. They’re like living toothbrushes and scrubs. And they work hard – every day, a single cleaner inspects over two thousand clients, and some clients visit the stations more than a hundred times a day.
The cleaners, and their relationships with their clients, make a classic case study for biologists studying the evolution of cooperation. The tiny fish clearly get benefits in the form of a meal, and they enjoy a sort of diplomatic immunity from otherwise hungry hunters. On the face of it, the clients also benefit by getting scrubbed of harmful parasites. Now, Peter Waldie from the University of Queensland has shown how important this hygiene is.
Christian Wentz from MIT has designed a hat that wouldn’t look out of place at a horse race or a royal wedding. It consists of two circuit boards and an antenna, and it’s being modelled by a mouse. Wentz has wired the hat directly to the mouse’s brain and he can use it to control the animal’s behaviour with flashes of light. And most importantly, he can do it from afar.
The wireless helmet is the latest innovation in the exciting field of optogenetics, where scientists can use light to control the behaviour of both cells and entire animals. The typical set up involves loading cells – usually neurons – with a light-sensitive gatekeeper protein. When the protein sees the light, it opens up and allows ions to enter the neuron, making it fire.
The good news for all new parents is that scientists have found a way of sending individuals straight to sleep by turning up the thermostat. The bad news is that it only works in flies. Alas, this technique is not going to solve anyone’s sleepless nights, but it could tell us something about why we sleep at all.
Every animal, or at least every one with a brain, needs to sleep, but it’s still not entirely clear why. William Dement, who has been studying sleep for six decades, once said, “As far as I know, the only reason we need to sleep that is really, really solid is because we get sleepy.” As Daniel Bushey from the University of Wisconsin writes, “Sleep is perhaps the only major behaviour still in search of a function.”
People with type 2 diabetes don’t respond properly to insulin, a hormone that controls the levels of sugar in their blood. Many of them have to take tablets to keep their sugar levels down, while others rely on insulin injections. But in a Swiss laboratory, there are diabetic mice with a more convenient solution. If they need more insulin, all they need is to bathe under a blue light.
The mice are the work of Haifeng Ye from ETH Zurich, who has developed a way of turning on individual genes with bursts of light. Blue light in particular sets of a chemical chain reaction in the rodents’ bodies that eventually switches on a gene called GLP-1. It tells the pancreas to make more insulin, makes our cells more sensitive to this hormone, and makes us feel full.
Ye’s work is a fusion of two of the most exciting methods in biology: optogenetics, the ability to control events in a cell using bursts of light; and synthetic biology, the building of new biological circuits that don’t exist in nature. In a related editorial, Brian Chow and Ed Boyden (one of the founders of optogenetics) call the new technique “synthetic physiology”.
The wasp Dinocampus coccinellae is a body-snatcher, or perhaps a “bodyguard-snatcher”. She’s on the hunt for a spotted ladybird. When she finds one, she stings it and lays an egg inside its body. Her grub hatches and starts eating the ladybird alive. Around three weeks later, it bursts out of its host.
But the ladybird doesn’t die. The grub hasn’t consumed all of its internal organs, and it leaves the ladybird partially paralysed but very much alive. Once out, it spins a silken cocoon between the ladybird’s legs and over the next week, it slowly transforms into an adult. Meanwhile, the ladybird stands guard over its own parasite. Its warning colours of red and black should deter would-be predators, and it twitches erratically if threats draw near. Its tour of duty only ends when the adult wasp eventually emerges from the cocoon and flies away.
Many birds have a compass in their eyes. Their retinas are loaded with a protein called cryptochrome, which is sensitive to the Earth’s magnetic fields. It’s possible that the birds can literally see these fields, overlaid on top of their normal vision. This remarkable sense allows them to keep their bearings when no other landmarks are visible.
But cryptochrome isn’t unique to birds – it’s an ancient protein with versions in all branches of life. In most cases, these proteins control daily rhythms. Humans, for example, have two cryptochromes – CRY1 and CRY2 – which help to control our body clocks. But Lauren Foley from the University of Massachusetts Medical School has found that CRY2 can double as a magnetic sensor.