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David Funk

Male Crickets Bribe Their Mates With 'Gummy Bears'

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David Funk

Everybody likes getting presents. It’s this fact that makes gift-giving such an important form of social currency: People give presents to celebrate and reward one another, and use them as apologies, distractions, and bribes. But humans aren’t the only ones who give gifts for selfish reasons. 

A new study authored by scientists from the University of Exeter and the Max Planck Institute for Chemical Ecology and published last week in PLOS ONE, has found that a male cricket’s postcoital “nuptial gift” to his mate is really more of a gift to himself. The gift, a gelatinous blob called a spermatophylax, can manipulate a female cricket into becoming a mother.

Nuptial gifts are a common feature of courtship in the animal kingdom, especially for insects. Before, during, or after sex, male animals present their mates with food or pretty objects. Gifts of food deliver an extra boost of protein or nutrients. Those nutrients will be passed on to the female’s eggs, making the next generation a little hardier and stronger.

But the nuptial gift of the decorated cricket, Gryllodes sigillatus, does none of these things. The sweet and chewy spermatophylax has no nutritional value whatsoever. “They’re a sham,” Illinois State University entomologist Scott Sakaluk told Nautilus last year. The gift is “the equivalent of a gummy bear,” he said. “Gummy bears are really tasty, but you can’t live off gummy bears.”

A spermatophylax doesn’t just fall out of the sky; the male cricket has to devote a lot of resources to making it. And he wouldn’t do that if it weren’t worth his time. So what’s it for? 

Manipulation. It looks so innocent, but the gummy bear is a Trojan horse. By eating the male cricket’s gift, the female cricket unwittingly takes part in ensuring her tricky mate’s legacy.

Scientists already knew about the first phase of the subterfuge: distraction. After mating, the male cricket deposits a small packet of sperm and a big nuptial gift at the tip of the female’s ovipositor. (You can see both in the image above; the spermatophylax is the big, clear blob, while the sperm packet is smaller and cloudy.) 

Unlike the gift, the sperm packet actually is nutritious, and the female will eat it if she gets the chance. But before she can get to it, she finds the gift. It can take her up to 50 minutes to eat the cricket candy—which is, on average, as long as it takes for the sperm to transfer into her body. The bigger the gummy bear, the better the chance that a male’s sperm will be successful in their quest.

But the deception goes so much deeper. In their study published in PLOS ONE, the researchers reported that compounds in the cricket’s nuptial gift seem to change the female cricket’s body and behavior.

The team found two types of proteins in the spermatophylax. One is protective, and keeps the female cricket’s gut from digesting the second protein. That protein may have two purposes: first, to beef up the female’s reproductive system, and second, to kill her sex drive and keep her from mating with anyone else.

So the cricket’s nuptial gift may be less like a gummy bear and more like a gummy vitamin—one the female cricket has no idea she’s taking. 

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Big Questions
Why Do Cats Freak Out After Pooping?
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Cats often exhibit some very peculiar behavior, from getting into deadly combat situations with their own tail to pouncing on unsuspecting humans. Among their most curious habits: running from their litter box like a greyhound after moving their bowels. Are they running from their own fecal matter? Has waste elimination prompted a sense of euphoria?

Experts—if anyone is said to qualify as an expert in post-poop moods—aren’t exactly sure, but they’ve presented a number of entertaining theories. From a biological standpoint, some animal behaviorists suspect that a cat bolting after a deposit might stem from fears that a predator could track them based on the smell of their waste. But researchers are quick to note that they haven’t observed cats run from their BMs in the wild.

Biology also has a little bit to do with another theory, which postulates that cats used to getting their rear ends licked by their mother after defecating as kittens are showing off their independence by sprinting away, their butts having taken on self-cleaning properties in adulthood.

Not convinced? You might find another idea more plausible: Both humans and cats have a vagus nerve running from their brain stem. In both species, the nerve can be stimulated by defecation, leading to a pleasurable sensation and what some have labeled “poo-phoria,” or post-poop elation. In running, the cat may simply be working off excess energy brought on by stimulation of the nerve.

Less interesting is the notion that notoriously hygienic cats may simply want to shake off excess litter or fecal matter by running a 100-meter dash, or that a digestive problem has led to some discomfort they’re attempting to flee from. The fact is, so little research has been done in the field of pooping cat mania that there’s no universally accepted answer. Like so much of what makes cats tick, a definitive motivation will have to remain a mystery.

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

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Animals
Watch a School of Humpback Whales 'Fish' Using Nets Made of Bubbles 

Just like humans, humpback whales catch many fish at once by using nets—but instead of being woven from fibers, their nets are made of bubbles.

Unique to humpbacks, the behavior known as bubble-net feeding was recently captured in a dramatic drone video that was created by GoPro and spotted by Smithsonian. The footage features a school of whales swimming off Maskelyne Island in British Columbia, Canada, in pursuit of food. The whales dive down, and a large circle of bubbles forms on the water's surface. Then, the marine mammals burst into the air, like circus animals jumping through a ring, and appear to swallow their meal.

The video offers a phenomenal aerial view of the feeding whales, but it only captures part of the underwater ritual. It begins with the group's leader, who locates schools of fish and krill and homes in on them. Then, it spirals to the water's surface while expelling air from its blowhole. This action creates the bubble ring, which works like a net to contain the prey.

Another whale emits a loud "trumpeting feeding call," which may stun and frighten the fish into forming tighter schools. Then, the rest of the whales herd the fish upwards and burst forth from the water, their mouths open wide to receive the fruits of their labor.

Watch the intricate—and beautiful—feeding process below:

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