Deench

Everything for Everyone

Erectile function: bats mop up nectar with “hairy” tongues

As sweet as the reward is, it isn’t easy being a nectar-feeder. Bats, hummingbirds, and bees face the difficult task of sipping as much nectar as possible from a tiny floral tube, all while hovering delicately in the air. And since hovering is such an energy-demanding task, the more efficiently these animals can slurp up nectar, the likely they are to get something out of a visit to a flower.

Hummingbirds have evolved a creative adaptation to deal with this challenge: the tips of their long tongues are bifurcated, or split. During feeding, nectar is trapped between the two tongue tips and carried into the bird’s mouth. Long-tongued bees have solved the problem in a slightly different way: they have a brush-like structure on the end of their tongue to help lap up nectar. Nectar-feeding bats have similar hairy projections on the end of their tongue, and researchers have long assumed that these were simply static structures that increased the surface area of the tongue to make nectar feeding more efficient.

However, a new study in PNAS suggests that a nectar-feeding bat’s tongue is far more efficient—and more complicated—than scientists previously assumed.

Read 6 remaining paragraphs | Comments

Stressed out moms mean faster growing babies—if you’re a squirrel

To give her offspring better odds in life, a mom can contribute all sorts of advantages: good genes, healthy milk, protection from predators, and more. Red squirrels—cousins of the more robust gray squirrels—are no exception. But new research in the journal Science shows that for these rodents, one such maternal boost stems from a surprising source: stress.

The research was conducted by a group of scientists who have spent the last 22 years studying a group of wild red squirrels in the Yukon. The ecosystem there follows an episodic pattern: every few years, when the spruce trees produce seeds en masse, the squirrel population booms in response. The team’s previous research had shown that in the years when squirrel numbers are especially high, fast-growing offspring tend to fare better than those that grow more slowly, presumably since they are better equipped to outcompete their rivals.

But how, exactly, do some squirrels end up growing so quickly?

Read 9 remaining paragraphs | Comments

When it comes to vaccination, bad news is contagious

In recent years, the controversy about vaccine safety has exploded online. Fueled by pseudoscience, conspiracy theories, and ignorance, a surprisingly large number of people today refuse to vaccinate themselves or their children. According to a 2011 poll, nearly a quarter of Americans have changed their opinion on vaccination in the last five years, and for the vast majority of these people, that change has been in a negative direction.

There’s no better tool than social media to spread information—and misinformation—about controversial topics quickly and efficiently, and there has been speculation that these outlets have played a role in heightening concerns about vaccination. But how do opinions about health-related behaviors spread over social media?

A group of researchers from Penn State used Twitter to answer this question, and their findings were published in EPJ Data Science last week.

Read 9 remaining paragraphs | Comments

By building “fairy circles,” termites engineer their own ecosystem

The Namib Desert is dotted with thousands of mysterious “fairy circles,” which are near-perfect circles of barren soil two to fifteen meters wide, rimmed by tall grass. They are unmistakable and stretch for miles, giving the landscape an ethereal and otherworldly feel. Many possible explanations have been proposed, including toxic substances in the soil, meteorites, termites, UFOs, and the ghosts of dead natives. But the circles are extremely remote—more than 110 miles from the nearest village—and have been difficult to study scientifically. Despite decades of research, the cause of these bizarre circles has remained elusive.

But now, after a six-year study and more than 40 trips to the Namib Desert, Dr. Norbert Juergens believes he has come to understand the biological underpinnings of this strange phenomenon. According to Juergens, a single species of termites is responsible for creating and maintaining the circles. But the barren circles aren't just a byproduct of these tiny insects living below the sandy desert surface; they are part of a carefully cultivated landscape that helps the termites—and many other organisms—thrive in an otherwise inhospitable climate.

Juergens hypothesized that if the fairy circles’ cause was biological, the organism would need to co-occur with the circles and would probably not be found elsewhere. Only one species fit the bill: Psammotermes allocerus, the sand termite. Not only was the sand termite the only insect species that lived across the entire range of the fairy circles, but these termites were found to be living beneath nearly every circle sampled. And the harder the termites worked – foraging, burrowing, and dumping their refuse – the more grass died, leading Juergens to conclude that the termites keep the circles barren by burrowing underground and foraging on the roots of germinating grasses.

Read 6 remaining paragraphs | Comments

Action-packed video games may help dyslexic kids learn to read

For children with dyslexia, learning to read can be a nightmare: to them, it's a jumble of words, letters, and sounds that is impossible to make sense of. Studies show that dyslexia is a disorder of the brain (rather than of the visual system), but since scientists still don’t know the root cause, there’s no simple way to combat the disorder. Traditional treatments and therapies for the dyslexia are time-consuming, expensive, and don’t necessarily bring huge improvements.

One of the hallmarks of dyslexia is what researchers call "attentional dysfunction;" this deficit makes it hard for dyslexics to focus their attention and pick out important information in a cluttered environment. To attack this deficit head-on, a group of Italian researchers wondered whether children with dyslexia would benefit from intense immersion in an activity that forced them to practice these skills. Specifically, would playing active video games help dyslexic kids learn to focus their attention, making it easier for them to learn to read?

The answer was a resounding yes, according to the research detailed in Current Biology this week.

Read 7 remaining paragraphs | Comments

Mass whale strandings aren’t all in the family

Each year, more than a thousand marine mammals die during mass strandings, which are grisly events in which large numbers of whales or dolphins become beached on the shore together. But scientists still don’t know exactly why these strandings occur. Climatic events, unfamiliar underwater topography, and noise from seismic surveys and naval exercises have all been suggested to play a role. In another theory based on family ties, one or a few whales, driven by disease or starvation, veer off in the wrong direction and draw well-meaning family members into shallow, dangerous waters as they try to help.

However, a paper in this week’s Journal of Heredity suggests that the role of relatives in mass strandings may not be quite so straightforward.

The researchers collected skin samples and information about the spatial distribution of 490 long-finned pilot whales stranded in 12 events across New Zealand and Tanzania. By studying the whales’ mitochondrial DNA (a type of genetic information passed on from mother to offspring), the researchers could determine how closely-related the stranded animals were.

Read 3 remaining paragraphs | Comments

Plants make bees remember them fondly with a jolt of caffeine

Aurich Lawson / Thinkstock

As tiny as they are, bees are an incredible source of information for scientists, contributing to our knowledge in areas from agriculture to navigation. Just last week, we reported that bees use the electric fields of flowers to identify profitable plants, an ability that helps them forage more efficiently. A study in today’s issue of Science identifies another surprising cue that can play a significant role in bees' foraging behavior: caffeine.

Several plants, including species in the genuses Coffea and Citrus, produce nectar that contains caffeine; the concentration of caffeine in some of these flowers rivals that in a cup of instant coffee. We know what effects caffeine has on humans, but how does caffeinated nectar affect bees pollinating these plants?

To answer this question, the researchers taught bees to associate the odor of a particular chemical, called 1-hexanol, with a sugary reward. For some of the bees, the scientists added a small dose of caffeine to the sucrose reward solution in order to determine whether the consumption of caffeine affected how well the bees learned or remembered the association.

Read 5 remaining paragraphs | Comments

In new bodies, brain cells find longer lives

The search for the fountain of youth is nothing new; we humans have long been trying to lengthen our lifespans. In recent years, science and medicine have made great strides in increasing how long we live. The average life expectancy of an American is now more than 78 years, up nearly a decade since 1960. But as we live longer and longer, what will happen to the cells that compose our brains?  If we are able to live to 120, 150, or longer, can our brain cells survive that long too? Or in the future, will our neurons die long before we do, leaving our brains depleted?

To start answering this question, three Italian researchers carried out a series of transplant experiments and found that neurons can last far longer than the organisms in which they originated. In this week’s issue of PNAS, the scientists describe their research, which suggests neuron survival may be more flexible than previously thought.

The researchers chose to work with mice and rats. The two animals are similar in many regards, but they differ substantially in their life expectancy (rats survive far longer than mice). By transplanting cells between these two species, the scientists could determine whether neurons have a pre-programmed lifespan based on genetics or whether they have more plasticity.

Read 7 remaining paragraphs | Comments

Bees can sense—and learn from—the electric fields of flowers

My, what delicious electrons.
NASA

Flowers offer all sorts of cues to their pollinators—colors, patterns, shapes, and scents all help plants communicate with butterflies, bats, birds, and bees. But recent research suggests that another type of information—electrical fields—may work in concert with these other cues to provide extremely nuanced details about pollination status. This week in the journal Science, researchers show that this may play an important role in the extremely close-knit relationship between flowers and their pollinators.

As they travel through the air, bumblebees lose electrons, accumulating a small positive electrical charge. Flowers, meanwhile, are generally negatively charged at the top, thanks to a slight positive charge in the air around them. As a bee approaches a flower, a tiny electric field is created between plant and pollinator.

In the past, scientists have suggested that these differing charges encourage the transfer of pollen between flower and bee, helping the tiny pollen grains “jump” onto the pollinator. However, the new study showed that the bee’s landing actually influences the flower’s electrical charge—increasing it slightly—for a short period of time. The study's authors hypothesize that this change may signal to the next bee that the flower has just been visited and that its nectar stash is depleted. Other cues, such as a flower’s shape or color, sometimes change in response to a bee’s visit, but these changes can take hours. The electrical field, on the other hand, changes almost instantaneously, providing a nearly immediate signal to incoming bees.

Read 5 remaining paragraphs | Comments

Anti-anxiety drugs in wastewater impact fish behavior

Benzodiazepines are a highly effective group of pharmaceutical drugs that help millions of people cope with anxiety, insomnia, and panic disorders each year. These drugs work by binding to receptors in the brain and enhancing the effect of a neurotransmitter called GABA.

But humans aren’t the only animals with GABA and GABA receptors; several other species—including many types of fish—are similar to us in this aspect of their brain chemistry. And, thanks to the huge amount of prescription drugs that are flushed down the drain (American medical care facilities alone may flush as much as 250 million pounds of pharmaceuticals a year), these species are inadvertently being exposed to high concentrations of benzodiazepine in rivers, lakes, and streams.

In this week’s issue of Science, a group of researchers shows exposure to these drugs can cause significant behavioral changes in fish, changes that could potentially alter ecosystem dynamics.

Read 8 remaining paragraphs | Comments