A burrow is just a hole in the ground, right? Wrong. Different species of mice have very different burrow designs, and
a new study suggests that a mouse’s architectural know-how is written in its DNA: Mice constructed these species-specific burrows even when they had never seen one before.
Researchers examined the burrowing behaviors of two related mouse species. The deer mouse makes a simple burrow, just a short tunnel that leads to a nest. The closely related oldfield mouse puts a little more feng shui in its design, extending the entry tunnel and adding a back door for quick escapes from the nest. To see if the blueprints for these burrow designs were based on instinct, researchers brought the mice into the lab.
Before they can talk, babies use gestures to communicate: sentiments such as “take this away,” “look over there,” and “put me down” can be made abundantly clear without words. Chimps gesture to each other, as well, pointing out particular spots where they’d like to be scratched or groomed. These symbolic gestures are believed to be an important precursor to language. Now, researchers have observed ravens using gestures in the wild—the only non-primates seen doing so.
Heliconius numata (top) mimics the wing
pattern of Melinaea mneme (bottom).
What’s the News: A single species of butterfly in the Amazon is able to copy the wing patterns of several neighboring species to avoid being eaten by hungry birds—a wide-ranging talent that has long perplexed evolutionary biologists. Now, an international team of scientists studying the mimicking butterfly Heliconius numata has finally solved this puzzle that plagued even Charles Darwin.
Writing in the journal Nature, researchers found that a specific supergene—a cluster of genes that is passed on to offspring as one big chunk—controls the different elements of wing patterns, allowing related butterflies to display distinct markings despite having the same DNA. “These butterflies are the ‘transformers’ of the insect world,” lead researcher Mathieu Joron said in a prepared statement. “But instead of being able to turn from a car into a robot with the flick of switch, a single genetic switch allows these insects to morph into several different mimetic forms.”
What’s the News: In the squid world, the body size of male spear squid determines the mating strategies they use. Small male squid, which have no chance of physically competing with their larger rivals, must try to get with the females of the species on the sly. Now, researchers in Tokyo have learned that this difference in mating behavior has resulted in the evolution of divergent sperm types, though perhaps not in the way you’d think: diminutive male squid actually produce larger sperm than big male squid.
Researchers at Wake Forest University in North Carolina have now learned that Nazca boobies perpetuate a “cycle of violence”: bullied chicks tend to become bullies and pass on the pain. When parent birds leave their nests to eat, baby boobies are often visited by sexually and physically abusive non-breeding adults; the chicks, when grown, are more likely to abuse unrelated chicks. “The link we found indicates that nestling experience, and not genetics, influences adult behaviour,” lead researcher David Anderson told BBC.
In Australia’s Great Barrier Reef, a professional diver has photographed a blackspot turkfish smashing a clam against a rock to get the tasty treat on the inside—this appears to be the first documented case of a fish using a tool. But some people argue that this behavior, which is similar to a seagull cracking open a shell by dropping it onto a hard surface, does not constitute tool use because the “tool” is fixed and the animal never actually holds it.
See a nice round-up video of the news and the tool-use debate at HuffPost.
Image: Scott Gardner/Coral Reefs, DOI:10.1007/s00338-011-0790-y
What’s the News: A few years ago scientists learned that American crows can recognize and remember human faces, particularly faces they associate with bad experiences. Now, new research published in the Proceedings of the Royal Society B shows that the birds can share that knowledge of dangerous humans with other crows.
What’s the News: Parrots are even less bird-brained than previously thought, suggests a new study in the journal Biology Letters. In a series of tests, researchers have learned that some African grey parrots can use logical reasoning to uncover hidden food.
Yesterday we reported on a new study that showed shining a laser on certain neurons in mice brains could make them angry and aggressive. But with squid, you don’t need a laser to make the males get mean. All you need is to expose them to a particular chemical. From DISCOVER blogger Ed Yong:
In a flash, schools of male longfin squid can turn from peaceful gatherings to violent mobs. One minute, individuals are swimming together in peace; the next, they’re attacking one another. The males give chase, ramming each other in the sides and grappling with their tentacles.
These sudden bouts of violence are the doing of the female squid. Males are attracted to the sight of eggs, and females lace the eggs with a chemical that transforms the males into aggressive brutes.
For plenty more about how this chemical whips the males into an angry frenzy—and why—check out the rest of Ed’s post at Not Exactly Rocket Science.
Not Exactly Rocket Science: A Squid’s Beak is a Marvel of Biological Engineering
Not Exactly Rocket Science: Tears as chemical signals – smell of female tears affects sexual behaviour of men
80beats: A Blast of Light to the Brain Can Make Mice Mean
The first study of sleep in bees, published this week in the Proceedings of the National Academy of Sciences, found that the tired bees lag just like sleep-deprived humans do. Too bad bees don’t have coffee. Says lead researcher Barrett Klein:
“When deprived of sleep, humans typically experience a diminished ability to perform a variety of tasks, including communicating as clearly or as precisely. We found that sleep-deprived honey bees also experienced communication problems. They advertised the direction to a food site less precisely to their fellow bees.” [Daily Mail]
So how do you keep bees awake when they don’t need to cram for a calculus final? You make them magnetic. Klein attached a piece of either steel or non-magnetic metal to the bees’ backs. Then all through the night, the researchers swung a magnet over the hive three times a minute–a device they call the “insominator.” This jostled the bees with the magnetic steel on their backs and kept them from sleeping.