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This Caterpillar’s Stink Breath Keeps the Spiders Away

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Bad breath usually won’t win you many friends, but at least it will keep your enemies at arm’s length, too. The larval caterpillar form of a moth called the tobacco hornworm, scientists have discovered, uses a blast of nasty air to fend off wolf spiders and other predators. The source of the stench is the hornworm’s preferred meal: tobacco leaves. 

While human smokers look to nicotine as a stimulant, the tobacco plants it comes from use it as a defense against insects and other animals that would eat them. Nicotine is a poison, and an exceptionally fast-acting one, racing from the lungs to the brain in just seven seconds after inhalation. At a dose of 30 to 60 milligrams, it can cause convulsions, respiratory failure, and death (smokers only get about 1mg of it from each cigarette, FYI). 

Nasty stuff, and a good reason why most animals don’t munch on tobacco too much. The hornworm has a workaround for this, though, and can tolerate doses of nicotine hundreds of times higher than what would kill most other animals. Even the hornworm doesn’t hang on to the poison for long, though, and rapidly disposes of most of the nicotine in its waste. While getting rid of the nicotine, it can use a little bit of its food’s chemical weaponry as its own, and a team of German ecologists show in a new study how hornworms dispose of the chemical in an alternate way that helps defend them from predators. 

The researchers, from the Max Planck Institute for Chemical Ecology, found that a gene called CYP6B46 redirects some of the nicotine from the hornworm’s gut into their hemolymph, the arthropod analogue of blood, where it hinders and kills parasites. From the hemolymph, the nicotine can also be exhaled through breathing holes on the hornworm’s body called spiracles, creating a spider-repelling “defensive halitosis.”

Here’s a poor hornworm with its CYP6B46 gene silenced. The spider chows down on it without a second thought.  

And here’s a spider versus a normal caterpillar and its noxious nicotine breath. After a face full of that, the spider tries to make a getaway up the side of the Dixie cup. 

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Animals
Why Male Hyenas Have It Worse Than Females
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A life of hunting zebras and raising young on the savanna isn’t half bad for a female hyena. Sadly, the same can’t be said for their male counterparts. As MinuteEarth explains, things take a downturn for the males of the species once they hit adolescence. No female in their pack will mate with them, a behavior scientists believe evolved to avoid inbreeding, so they head off in search of a different group to join. After dealing with vicious hazing from their new clan, they file in at the bottom of the rank and wait for other males above them to die so that they can slowly gain status.

Even after rising through the hierarchy, the most a male hyena can aspire to is being second place to the lowest-ranking female. Thanks to their bulky build and aggressive behavior, female hyenas enjoy a dominant position that’s rare in the animal kingdom.

After watching the video below, head over here for more facts about hyenas.

[h/t MinuteEarth]

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Art
A Beached Whale Sculpture Popped Up on the Banks of Paris's Seine River
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In Paris, dozens of fish varieties live in the Seine River. Now, the Associated Press reports that the famous waterway is home to a beached whale.

Rest assured, eco-warriors: The sperm whale is actually a lifelike sculpture, installed on an embankment next to Notre Dame Cathedral by Belgian artists’ collective Captain Boomer. It’s meant to raise environmental awareness, and evoke "the child in everyone who still is puzzled about what is real and what is not,” collective member Bart Van Peel told the Associated Press.

The 65-foot sculpture has reportedly startled and confused many Parisians, thanks in part to a team of fake scientists deployed to “survey” the whale. One collective member even posted a video on social media, warning Parisians that there “may be others in the water” if they opt to take a dip in the river, The Local reported.

The whale sculpture is only temporary—but as for Captain Boomer, this isn’t their first whale-related stunt. Last summer, the collective installed a similar riverside artwork in Rennes, France, and they also once strapped a large-scale whale sculpture to the back of a truck and drove it around France.

[h/t Associated Press]

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