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How Spiders Win the Lottery

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On a cloudy spring day, a little spider scales a tall blade of grass. At the peak, the spider arches up, points its abdomen up to the sky and begins releasing strands of silk from its silk glands. Tens of thousands of strands fill the air, fanning out and then coming back together to form a triangular sheet. A passing breezes catches the silk and suddenly the spider is airborne, riding its homemade parachute into the wild blue yonder.

Spider use these “ballooning” flights to escape from danger and to colonize new habitats. Most times, they only travel a few feet, but the right conditions can carry a spider over vast distances. Sailors have found them landing on ships thousands of miles from shore, and scientists have discovered eight-legged travelers in air samples collected by atmospheric data balloons.

All sorts of tiny arthropods travel this way, and some plants and fungi also use the wind to spread seeds, spores and pollen. Scientists call it passive airborne dispersal and from our perspective, passive is the key word. The tiny flyers seem to be left at the mercy of the elements and there seems to be little opportunity for them to strategize or make the most of their trip. The direction and distance they travel—or whether they travel at all or get stuck waiting to take off—are decided by the movement, direction and speed of the air.

Some researchers dub it the “aerial lottery.” The flyer buys their ticket, catches a breeze and crosses their metaphorical fingers that they land safely in a place they want to be. Whether they’ve won (new habitat, safe from danger, yay) or lost (atmospheric data balloon, boo) isn’t revealed until they’ve landed, and by then their play is over.

The journey appears completely out of their hands, yet many passive dispersers wind up exactly where they should want to be: still sort of close to where they started (where there are reliable, if shrinking, resources), but away on their own with untapped resources and no competition from their fellow spiders/seeds/whatever-they-ares. This winning play is the “shortest unique flight,” similar to the “lowest unique bid” needed to win some auctions and games. Despite all appearances, then, there may be a way to improve one’s odds of winning.

The trick to winning the aerial lottery, scientists think, is all in the take off, the last stage of the game where the “player” still has some control. Plants and fungi have been known to launch their wind-dispersed pollen, spores and seed only in certain conditions. Spiders and other wind-sailing critters, meanwhile, can choose the time and location of their launch.

New research by Andy M. Reynolds from the UK’s Rothamsted agricultural research station suggests that a winning strategy is based on taking flight in specific weather conditions. Warm, gentle breezes on days with some cloud cover are ideal for making the shortest unique flight. In more stable conditions the flight might be unique, but will last longer. In less stable conditions, the flights are shorter but less likely to be unique. The ideal launch seasons, Reynolds suggests, are spring and autumn, exactly when spiders tend to ramp up their “ballooning behavior.”

Whether these creatures win or lose at their lottery is more relevant to us than you might think at first. Spiders are a great help in controlling pests, and knowing where and when they take flight can benefit farmers. “Each day of the growing season around 1,800 spiders land in each hectare of arable farmland after ballooning,” Reynolds said in a statement about the study. “If the farmers can predict the influx of spiders, they can reduce the amount of pesticides accordingly," saving money and hassle. Similarly, being able to predict the spread of problematic fungi can help control them and the diseases they cause, giving us a leg up in this strange game of chance.

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Slow Motion Is the Only Way to Appreciate a Chameleon’s Lightning-Fast Tongue
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From the unusual way they walk, to their ability to change color, the evolutionary adaptations of chameleons are pretty bizarre, and some of them remain mysterious even to scientists. Their super-powered tongues, for instance, can dart out so quickly that the movement can barely be seen with the naked eye. But modern high-speed cameras have enabled researchers at the University of South Dakota to observe this appendage at work like never before. The video below, shared over at The Kid Should See This, includes some of that groundbreaking footage, and it's pretty amazing to watch.

Shooting at 3000 frames per second, the camera was able to capture every split-second aspect of the chameleon's tongue strike. Slowed down, the video allows you to see how every component of the process works in harmony: First, muscles in the lizard’s tongue contract like the string of a bow. Then, when that tension is released, the bony base of the tongue shoots forward, pushing the sticky, elastic part toward the chameleon’s prey.

According to Christopher Anderson, one of the scientists who conducted the high-speed camera research, larger chameleons can catapult their tongues forward at distances of one to two times their body length. For smaller chameleons, this distance can reach up to two and a half times their body length. “Small chameleons need to be able to eat more food for their body size than large chameleons,” he tells bioGraphic in the video, “and so by being able to project their tongues proportionately further than these large species, they basically are opening up additional feeding opportunities to themselves that they wouldn’t have if they had a shorter tongue.”

To see one of nature’s greatest hunting tools in action, check out the full video below.

[h/t The Kid Should See This]

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There May Be an Ancient Reason Why Your Dog Eats Poop
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Dogs aren't known for their picky taste in food, but some pups go beyond the normal trash hunting and start rooting around in poop, whether it be their own or a friend's. Just why dogs exhibit this behavior is a scientific mystery. Only some dogs do it, and researchers aren't quite sure where the impulse comes from. But if your dog is a poop eater, it's nearly impossible to steer them away from their favorite feces.

A new study in the journal Veterinary Medicine and Science, spotted by The Washington Post, presents a new theory for what scientists call "canine conspecific coprophagy," or dogs eating dog poop.

In online surveys about domestic dogs' poop-eating habits completed by thousands of pet owners, the researchers found no link between eating poop and a dog's sex, house training, compulsive behavior, or the style of mothering they received as puppies. However, they did find one common link between the poop eaters. Most tended to eat only poop that was less than two days old. According to their data, 85 percent of poop-eaters only go for the fresh stuff.

That timeline is important because it tracks with the lifespan of parasites. And this led the researchers to the following hypothesis: that eating poop is a holdover behavior from domestic dogs' ancestors, who may have had a decent reason to tuck into their friends' poop.

Since their poop has a high chance of containing intestinal parasites, wolves poop far from their dens. But if a sick wolf doesn't quite make it out of the den in time, they might do their business too close to home. A healthier wolf might eat this poop, but the parasite eggs wouldn't have hatched within the first day or two of the feces being dropped. Thus, the healthy wolf would carry the risk of infection away from the den, depositing the eggs they had consumed away in their own, subsequent bowel movements at an appropriate distance before the eggs had the chance to hatch into larvae and transmit the parasite to the pack.

Domestic dogs may just be enacting this behavior instinctively—only for them, there isn't as much danger of them picking up a parasite at home. However, the theory isn't foolproof. The surveys also found that so-called "greedy eaters" were more likely to eat feces than dogs who aren't quite so intense about food. So yes, it could still be about a poop-loving palate.

But really, it's much more pleasant to think about the behavior as a parasite-protection measure than our best pals foraging for a delicious fecal snack. 

[h/t The Washington Post]

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