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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?

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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.

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Nest-making orangutans build for comfort and strength

Great apes are our closest relatives, and they are constantly surprising us with their human-like abilities and tendencies; here at Ars, we've seen studies showing that they plan ahead, they engage in wars over territory, and they respond to being tickled, just to name a few. Now, a new study in PNAS adds to the growing list of ways in which great apes are similar to us: they value a good night’s sleep, and they have the technological know-how to build pretty impressive beds from some very basic materials.

Many species of great ape, including chimpanzees, gorillas, bonobos, and orangutans, build nests in the forest canopy. Generally, these nests are slept in for just one night, then abandoned. The nests are thought to benefit the apes in several ways: sleeping above the ground reduces disturbances, protects them from predators, leaves them less vulnerable to mosquitoes and other pests, and generally increases the quality of their sleep. However, we know very little about how these nests are actually constructed. To figure out how much skill goes into nest-building, a group of scientists studied nests made by Sumatran orangutans in Indonesia.

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Bowerbirds woo mates with a lot of effort and a little illusion

Inherently, there’s a problem with the way we view the world: our world is three dimensional, while the image projected onto our retinas is just two dimensional. Therefore, without even being aware of it, we use clues to figure out distance and perspective in our environment. When an object gets smaller, it is becoming farther away; when it gets larger, it is approaching us.

New research in Science this week shows that we aren’t the only species that uses visual clues as a means to an end: male bowerbirds’ mating success depends on their ability to create a false sense of perspective.

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Bees reach consensus by headbutting dissenters

The human brain is wonderfully complex. Within it, there are billions of neurons, each collecting information and determining whether to respond to it. In some cases, groups of neurons compete for an outcome; when a group reaches a certain level of activity, its output ends up being chosen. To help make their case, these neurons can send positive signals to each other, and they can inhibit others with different agendas. Ideally, this system improves the chances of reaching an optimal decision; it’s an elegant way to make sense of lots of competing input.

As if we didn't think bees were cool enough already, Science reports this week that this approach to decision making is echoed in the behavior of honeybee swarms. Just as our neurons emit inhibitory signals, bees can hinder other hivemates that are advocating a different course of action. As with neurons, the swarm’s collective decision is made when a particular threshold is reached. But, unlike neurons, the bees have a very physical means of inhibiting those with a competing message: they headbutt them.

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Wasps with many queens will remember your face as they sting you

For most of us humans (and other species), the ability to recognize faces comes so naturally that we don’t even think about it. However, many other animals lack the ability to distinguish between individual faces, even when they are faces of their own species. Even closely related species within a single genus sometimes display variability in this type of individual recognition. So what determines whether an animal can learn to identify the faces of its conspecifics?

New research in Science suggests that face learning may be shaped by the specific ecology of individual species. To study this, researchers used Polistes fuscatus, a species of paper wasp, that is excellent at facial recognition. P. fuscatus has all the ingredients necessary for this cognitive ability: they have excellent vision, their nests are well-lit, their facial features are highly variable, and (perhaps most importantly) they have multiple queens. 

This life history detail may be the key to their facial recognition skills. Since there is more than one queen in each nest, having a hierarchy becomes important; wasps must learn who is who in order to avoid conflict and keep the colony stable.

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