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These Ants Use Mercenaries to Fight for Them

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In the jungles of Panama, a group of farmers ekes out a living by raising fungi for food. They’re peaceful, and when more aggressive neighbors come into their territory, looking for a cut of the crop, they oblige the guests and don’t fight them. While inconvenient, the arrangement pays off sometimes. When even more aggressive outsiders try to take over the farms, the first group of intruders earns their keep by repelling them and protecting their hosts. The not-exactly-welcome guests have their uses, and for the farmers, sharing a little fungus is a small price to pay for protection.

Humans have been using hired brutes to do their fighting for them for ages. Think of Blackwater Security, or Murder Inc., or Westeros’ most charming sellsword. But while the drama playing out in Central America echoes elements of Medieval history and The Magnificent Seven, none of the farmers, heroes, or villains here are people.

They’re ants.

The ants of the genus Sericomyrmex are peaceful farmers. They forage bits of vegetation, bring them back to their nests and grow fungus on them for food. Their lives aren’t all bucolic farmyard scenes in miniature, though. While many ants protect their colonies with specialized soldiers who can deliver powerful stings and bites, these six-legged agriculturalists are poorly armed, and can fight back only with their jaws. Unable to mount much of a defense against stinging foes, they’re regularly besieged by another ant species, Megalomyrmex symmetochus. Queens from this parasite species sneak into Sericomyrmex nests and form their own colonies within them, feeding on their hosts’ fungal crops, and sometimes their larva. They’ll also clip the wings of the virgin farmer queens, preventing them from forming new colonies and turning them into laborers. Instead of trying to fight the parasites and risk death, the farmers put up with them and supply them with room and board.

Biologists have found that the two groups are incredibly common with one another, and in some surveys, almost three quarters of Sericomyrmex nests are infested with Megalomyrmex. Even if they can’t fight back, why haven’t these farmers found some other way to rid themselves of their parasites?

One reason seems to be that the parasite is the lesser of two evils, and a good defense against an even bigger threat.

A third ant, Gnamptogenys hartmani, also raids the farmers’ colonies, taking over their gardens and nests and wiping out the inhabitants. The farmers are as defenseless against these pirates as they are against M. Symmetochus. G. hartmani has mastered a colony-conquering “agro-predator” lifestyle. Just two raiders can obliterate 70 percent of a Sericomyrmex colony, and the farmers that don’t perish usually flee and cede their home to the intruders.

When Gnamptogenys shows up at a Megalomyrmex-infested nest, though, the once unwelcome guest proves to be more of a help than a hindrance. The farmers will hide, while the more aggressive parasite soldiers confront and kill the invaders with their strong jaws and a little bit of chemical warfare. The Megalomyrmex ants possess a potent venom that they dole out through stings and by spraying into the air. It kills some of the raiders, and confuses others. The venom’s toxins appear to disrupt Gnamptogenys soldiers’ ability to recognize their nestmates, causing them to turn on each other and kill their own kind.

The arrangement hinges on a quirk of Megalomyrmex’s lifestyle. They don’t infest, eat, and move on like other parasites, but commit to a single host colony for life. Their success and survival depends on the farmers’ well-being.

To Rachelle Adams, an entomologist at the Smithsonian Institution whose research describes Megalomyrmex’s protective functions, the ants are more like mercenaries than pure parasites. They exploit their hosts, but that cost is compensated for by the defense they provide, and acting as soldiers for the farmers also protects their own interests. When trouble comes knocking, a parasitic win-lose relationship becomes a win-win.

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Big Questions
Do Cats Fart?
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Certain philosophical questions can invade even the most disciplined of minds. Do aliens exist? Can a soul ever be measured? Do cats fart?

While the latter may not have weighed heavily on some of history’s great brains, it’s certainly no less deserving of an answer. And in contrast to existential queries, there’s a pretty definitive response: Yes, they do. We just don’t really hear it.

According to veterinarians who have realized their job sometimes involves answering inane questions about animals passing gas, cats have all the biological hardware necessary for a fart: a gastrointestinal system and an anus. When excess air builds up as a result of gulping breaths or gut bacteria, a pungent cloud will be released from their rear ends. Smell a kitten’s butt sometime and you’ll walk away convinced that cats fart.

The discretion, or lack of audible farts, is probably due to the fact that cats don’t gulp their food like dogs do, leading to less air accumulating in their digestive tract.

So, yes, cats do fart. But they do it with the same grace and stealth they use to approach everything else. Think about that the next time you blame the dog.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at

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2017 Ig Nobel Prizes Celebrate Research on How Crocodiles Affect Gambling and Other Odd Studies
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The Ig Nobel Prizes are back, and this year's winning selection of odd scientific research topics is as weird as ever. As The Guardian reports, the 27th annual awards of highly improbable studies "that first make people laugh, then make them think" were handed out on September 14 at a theater at Harvard University. The awards, sponsored by the Annals of Improbable Research, honor research you never would have thought someone would take the time (or the funding) to study, much less would be published.

The 2017 highlights include a study on whether cats can be both a liquid and a solid at the same time and one on whether the presence of a live crocodile can impact the behavior of gamblers. Below, we present the winners from each of the 10 categories, each weirder and more delightful than the last.


"For using fluid dynamics to probe the question 'Can a Cat Be Both a Solid and a Liquid?'"

Winner: Marc-Antoine Fardin

Study: "On the Rheology of Cats," published in Rheology Bulletin [PDF]


"For their experiments to see how contact with a live crocodile affects a person's willingness to gamble."

Winners: Matthew J. Rockloff and Nancy Greer

Study: "Never Smile at a Crocodile: Betting on Electronic Gaming Machines is Intensified by Reptile-Induced Arousal," published in the Journal of Gambling Studies


"For his medical research study 'Why Do Old Men Have Big Ears?'"

Winner: James A. Heathcote

Study: "Why Do Old Men Have Big Ears?" published in the BMJ


"For their discovery of a female penis, and a male vagina, in a cave insect."

Winners: Kazunori Yoshizawa, Rodrigo L. Ferreira, Yoshitaka Kamimura, and Charles Lienhard (who delivered their acceptance speech via video from inside a cave)

Study: "Female Penis, Male Vagina and Their Correlated Evolution in a Cave Insect," published in Current Biology


"For studying the dynamics of liquid-sloshing, to learn what happens when a person walks backwards while carrying a cup of coffee."

Winner: Jiwon Han

Study: "A Study on the Coffee Spilling Phenomena in the Low Impulse Regime," published in Achievements in the Life Sciences


"For the first scientific report of human blood in the diet of the hairy-legged vampire bat."

Winners: Fernanda Ito, Enrico Bernard, and Rodrigo A. Torres

Study: "What is for Dinner? First Report of Human Blood in the Diet of the Hairy-Legged Vampire Bat Diphylla ecaudata," published in Acta Chiropterologica


"For using advanced brain-scanning technology to measure the extent to which some people are disgusted by cheese."

Winners: Jean-Pierre Royet, David Meunier, Nicolas Torquet, Anne-Marie Mouly, and Tao Jiang

Study: "The Neural Bases of Disgust for Cheese: An fMRI Study," published in Frontiers in Human Neuroscience


"For demonstrating that many identical twins cannot tell themselves apart visually."

Winners: Matteo Martini, Ilaria Bufalari, Maria Antonietta Stazi, and Salvatore Maria Aglioti

Study: "Is That Me or My Twin? Lack of Self-Face Recognition Advantage in Identical Twins," published in PLOS One


"For showing that a developing human fetus responds more strongly to music that is played electromechanically inside the mother's vagina than to music that is played electromechanically on the mother's belly."

Winners: Marisa López-Teijón, Álex García-Faura, Alberto Prats-Galino, and Luis Pallarés Aniorte

Study: "Fetal Facial Expression in Response to Intravaginal Music Emission,” published in Ultrasound


"For demonstrating that regular playing of a didgeridoo is an effective treatment for obstructive sleep apnoea and snoring."

Winners: Milo A. Puhan, Alex Suarez, Christian Lo Cascio, Alfred Zahn, Markus Heitz, and Otto Braendli

Study: "Didgeridoo Playing as Alternative Treatment for Obstructive Sleep Apnoea Syndrome: Randomised Controlled Trial," published by the BMJ

Congratulations, all.

[h/t The Guardian]


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