Aesop never penned a fable about a snail. If he had written about a certain freshwater mollusk, the moral might have been Boldness comes from a strong shell or maybe Careless snails get chomped. But because the snail and its variable shell are real, their lesson has more to do with the the weird workings of evolution.
Individual Radix balthica snails can have differently shaped shells. They also have varying “personalities,” at least as far as you can measure such a thing in a mollusk. To see whether their shells and personalities were linked, Johan Ahlgren, a researcher at Lund University in Sweden, gathered snail eggs from four nearby ponds.
Back in the lab, Alberg waited for the eggs to hatch. He fed the young snails algae and lettuce until they were grown. Then he subjected the animals to a personality test. Read More
Mary Poppins taught us that a spoonful of sugar makes the medicine go down. A bumblebee’s favorite sugary drink may already be laced with medicine. And bees seem to dose themselves with medicinal nectar when they’re suffering from a gut full of parasites.
Plants manufacture many chemical compounds to defend against attackers. Some of these are familiar to humans—like capsaicin, the potent weapon made by chili pepper plants. But not every animal enjoys painful food experiences like we do, and these defenses usually help keep hungry creatures away from a plant. Some are toxic or unpleasant for insects to eat, or protect against diseases. The compounds can also trigger incredible events in the plant’s environment. For example, a leaf being chewed by a caterpillar may send out signals that attract wasps, which arrive like cavalry to attack the pest.
Although these compounds are common in leaves and stems, they can also show up in nectar and pollen. If a flower relies on insects to pollinate it, this is confusing—why poison the nectar you want a bee to drink? Read More
To address a long-standing mystery in paleontology, scientists went to the grocery store.
Many dinosaur fossils appear in the same pose, not so much “terrible lizard” as “terrible limbo accident.” Their tails are stretched out and their necks thrown back grotesquely. But it’s not clear why this is. Researchers from the University of Calgary in Canada got a fresh take on the puzzle—or, at least, a recently killed and frozen take—by using dead chickens.
“Chickens are living dinosaurs, as are all birds,” says biologist Anthony Russell. Evolutionarily speaking, a chicken is closer to an extinct dinosaur than a crocodile is. So Russell and his student Adam Bentley, an undergraduate at the time, purchased 15 frozen whole chickens from a local grocery store. After thawing out the birds, the researchers put them to work. Read More
The history of Bahamas mosquitofish is written in their genitals. Though you’d have a hard time locating a female fish’s reproductive parts, they tell a story of predators, suitors, and finding a way to regain control.
Gambusia hubbsi arrived at Andros Island, in the Bahamas, about 15,000 years ago. The little fish live in vertical, water-filled caves called blue holes. Populations separated from each other by these caves are in the process of evolving into different species, pushed by the pressures of their particular homes. For example, in some blue holes, the fish live with few threats. In others, mosquitofish swim alongside their predator, a fish called the bigmouth sleeper (Gobiomorus dormitor). The color, shape, and swimming performance of mosquitofish have all evolved differently depending on whether these predators are around.
Another trait evolving differently across mosquitofish populations is their genitals. In the past, researchers studying mosquitofish—and other rapidly changing species—have focused on male genitalia. But North Carolina State University biologist Brian Langerhans thinks it’s time to take a closer look at females. Read More
Hungry mosquitoes use an arsenal of sensory tools to hunt you down. They sniff out the carbon dioxide you exhale; they home in on your heat signature. But a previously under-appreciated tool in the mosquito’s kit is the same one you use just before slapping at it in horror: vision.
At Caltech, Floris van Breugel put mosquitoes in a wind tunnel to tease apart how they find their meals. He used Aedes aegypti, a tropical species that spreads yellow fever and other diseases. The insects were all female, since female mosquitoes are the bloodsuckers.
The mosquitoes flew in a wind tunnel 1.2 meters long. Close to the upwind end was a dark spot on the floor—to a mosquito, this could be the shape of a person standing below, or some other animal worth checking out.
Then van Breugel pumped a plume of carbon dioxide into the tunnel. A whiff of this gas tells mosquitoes that somewhere nearby, an animal is exhaling. As the insects roamed around, he tracked their movements in three dimensions, producing maps of more than 20,000 individual flights. Read More
Any college student can tell you that overstudying is a waste of energy. When your resources are limited, you should learn the material that’s going to be on the test and ignore everything else. Certain blood-sucking bugs use the same strategy—unfortunately for the humans who catch diseases from them.
Kissing bugs live all around the Americas and drink the blood of other animals, including humans. They prefer to bite their hosts on the face—hence “kissing.” The species that live in the warmest areas, including Latin America and the southern United States, can carry the parasite that causes Chagas disease. This parasite can stay with a human for life and cause heart failure or other serious complications. (It doesn’t wriggle into your body while the bug is sucking your blood, but afterward, when the bug poops on your face.)
Understanding how kissing bugs operate, then, could be important for disease control. The insects have to learn and remember where to find their hosts and how to snack on them without getting smashed. How do those little brains work? Read More
Think your airline’s bag fees are burdensome? Try flying after swallowing part of your luggage and strapping the rest to your legs. That’s how bees do it. And depending on how a bumblebee loads herself up with nectar and pollen, her flight back to the hive might be less of a beeline than usual.
Like honeybees, bumblebees gather both nectar and pollen, bringing them back to the hive for food. They collect nectar simply by drinking it. After being slurped up a bee’s long tongue, nectar is stored in a kind of pre-stomach. Pollen, meanwhile, goes into “pollen baskets.” These are scoop-shaped surfaces on the bee’s back legs, surrounded by stiff hairs. After a flower sprinkles a worker bee with pollen, she can groom the grains into her baskets for storage. In the photo above, the big yellow blob on the bee’s haunch is a full pollen basket.
To learn how these loads affect bee flight, Harvard University researchers put bumblebees into wind tunnels and filmed them with high-speed cameras. Read More
You know that feeling when you’re halfway through a sentence and can’t think of the next word you need? It’s a word you know, but you can’t quite bring it to mind. There’s a name for that phenomenon…what is it, again?
Oh right, the “tip of the tongue.”
Everyday failures in our speech, like forgetting a word or saying the wrong one, are great fodder for scientists who want to understand language. But they’re hard to study in the lab, because you can’t force someone to make a mistake. Most of the time, we speak just fine.
So University of Kansas psychologist Michael Vitevitch has created an online tool for anyone, anytime, to record their speech errors. It’s like an ongoing goof diary for the public. And he hopes that if enough people use it, the data collected will be useful to the researchers who want to learn more about our minds. Read More
Just how much monkey business is there in monkey sex? In groups with alpha males, monkeys lower on the totem pole may have to sneak around to mate. How well they conceal their activities can shed light on the cognitive powers of primates.
Macaques are monkeys that live in troops with complex social hierarchies. High-ranking males may have dibs on mating with all the females in the group. But females give non-alpha males a chance too, and some studies have found that these hookups happen more often when the alphas are out of sight.
Researchers have defined three levels of “tactical deception” animals can employ. At the simplest level, an animal uses the same behaviors that it would normally, but in a context that leaves another animal out of the loop. (And it does this deliberately, not accidentally.) To reach the next level of deceptiveness, an animal has to understand another animal’s visual perspective: if I’m behind this bush, that gorilla can’t see me! And at the third level, animals actually try to manipulate each other’s knowledge.
Crows and apes have shown scientists that they can operate at the highest level of sneakiness. Monkeys and certain fish are known to deceive each other at the basic level. But there’s some evidence that monkeys can do better. Read More
Exercise scientist Conrad Earnest was dodging some oblivious pedestrians in England when inspiration struck. He was trying to walk down the sidewalk, but all around him people were weaving back and forth as they focused on their smartphone screens. Earnest suggested to two of his students that they study the dangers of texting while walking. Specifically, they could ask whether texters are more likely to trip and fall—perhaps wishful thinking on Earnest’s part as he walked among them.
The two University of Bath undergrads, Robynne Smith and Sammy Licence, dove into the project. A recent study by other researchers had looked at people who were texting while walking in a straight line. But for this study, they’d try to provide a challenge that was closer to a real-world sidewalk. Subjects would walk an obstacle course that included stairs, a curb, and even fake pedestrians. Read More