CLOSE
Original image
kadavoor via Wikimedia Commons // CC BY-SA 4.0

Male-Killing Microbe Meddles With Butterfly Mating

Original image
kadavoor via Wikimedia Commons // CC BY-SA 4.0

In the animal kingdom, much of the evolutionary process boils down to one thing: sex. In mating and passing on their genes, animals shape how future generations will look and behave. A steady stream of successful reproduction shapes a species. So what happens when that stream gets stopped up? Weird things. Scientists in Kenya have found two closely related butterfly populations living in close proximity yet unable to interbreed, thanks to a microbe that keeps killing off all the males. The researchers published their findings in the Proceedings of the Royal Society B.

The richly colored African Queen butterfly (Danaus chrysippus, also known as the "plain tiger") can be found across Africa, Europe, and Asia. There are three known subspecies: D. chrysippus chrysippus; D. chrysippus alcippus; and D. chrysippus orientis. Many of these butterflies carry a companion: the parasitic bacterium Spiroplasma ixodeti. Throughout most of the Queen’s realm, infection with the parasite is harmless. There’s just one place where Spiroplasma starts acting up: Nairobi, Kenya. Two subspecies—D. chrysippus chrysippus and D. chrysippus alcippus—call this area home, and both undergo some pretty intense changes when infected with Spiroplasma.

The bacteria effectively kills their children. But not all their children—just the males. It works like this: a female infected with Spiroplasma will lay both male and female eggs, but the male offspring will fail to hatch, and may be eaten by their sisters.

As a result, there are very few male African Queens of either subspecies in this region. The two mostly-female populations coexist but never interbreed, since, well, they couldn’t. Most males in the area are travelers from other, more normal regions. They, too, may carry the parasite or get it from their mates, but it doesn’t hurt them.

Elsewhere, African Queen subspecies intermingle freely, creating new wing color patterns through hybrid generations. Here though, a tiny bacterium has driven a genetic wedge between the two lady-led societies. In time, the subspecies could diverge so drastically that they become two different species altogether.

It’s all very strange, the authors say. Typically, speciation is driven by big changes in the environment, not tiny microbes.

Co-author Walther Traut is a biologist at the University of Lübbek. "This is like a smoking gun for the way in which species become distinct,” he said in a press statement. “It is rare that we can find the molecular basis for how species develop."

Know of something you think we should cover? Email us at tips@mentalfloss.com.

Original image
iStock
arrow
Big Questions
Why Do Cats Freak Out After Pooping?
Original image
iStock

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.

Original image
RODRIGO ARANGUA/AFP/GettyImages
arrow
Animals
Listen to the Impossibly Adorable Sounds of a Baby Sloth
Original image
RODRIGO ARANGUA/AFP/GettyImages

Sometimes baby sloths seem almost too adorable to be real. But the little muppet-faced treasures don't just look cute—turns out they sound cute, too. We know what you're thinking: How could you have gone your whole life without knowing what these precious creatures sound like? Well, fear not: Just in time for International Sloth Day (today), we have some footage of how the tiny mammals express themselves—and it's a lot of squeaking. (Or maybe that's you squealing?)

The sloths featured in the heart-obliterating video below come from the Sloth Sanctuary of Costa Rica. The institution rescues orphaned sloths, rehabilitates them, and gets them ready to be released back into the wild.

[h/t The Kid Should See This]

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios