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

Male-Killing Microbe Meddles With Butterfly Mating

kadavoor via Wikimedia Commons // CC BY-SA 4.0
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."

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Big Questions
What's the Difference Between Gophers and Groundhogs?
Gopher or groundhog? (If you chose gopher, you're correct.)
Gopher or groundhog? (If you chose gopher, you're correct.)
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Gophers and groundhogs. Groundhogs and gophers. They're both deceptively cuddly woodland rodents that scurry through underground tunnels and chow down on plants. But whether you're a nature nerd, a Golden Gophers football fan, or planning a pre-spring trip to Punxsutawney, Pennsylvania, you might want to know the difference between groundhogs and gophers.

Despite their similar appearances and burrowing habits, groundhogs and gophers don't have a whole lot in common—they don't even belong to the same family. For example, gophers belong to the family Geomyidae, a group that includes pocket gophers (sometimes referred to as "true" gophers), kangaroo rats, and pocket mice.

Groundhogs, meanwhile, are members of the Sciuridae (meaning shadow-tail) family and belong to the genus Marmota. Marmots are diurnal ground squirrels, Daniel Blumstein, a UCLA biologist and marmot expert, tells Mental Floss. "There are 15 species of marmot, and groundhogs are one of them," he explains.

Science aside, there are plenty of other visible differences between the two animals. Gophers, for example, have hairless tails, protruding yellow or brownish teeth, and fur-lined cheek pockets for storing food—all traits that make them different from groundhogs. The feet of gophers are often pink, while groundhogs have brown or black feet. And while the tiny gopher tends to weigh around two or so pounds, groundhogs can grow to around 13 pounds.

While both types of rodent eat mostly vegetation, gophers prefer roots and tubers (much to the dismay of gardeners trying to plant new specimens), while groundhogs like vegetation and fruits. This means that the former animals rarely emerge from their burrows, while the latter are more commonly seen out and about.

Groundhogs "have burrows underground they use for safety, and they hibernate in their burrows," Blumstein says. "They're active during the day above ground, eating a variety of plants and running back to their burrows to safety. If it's too hot, they'll go back into their burrow. If the weather gets crappy, they'll go back into their burrow during the day as well."

But that doesn't necessarily mean that gophers are the more reclusive of the two, as groundhogs famously hibernate during the winter. Gophers, on the other hand, remain active—and wreck lawns—year-round.

"What's really interesting is if you go to a place where there's gophers, in the spring, what you'll see are what is called eskers," or winding mounds of soil, Blumstein says [PDF]. "Basically, they dig all winter long through the earth, but then they tunnel through snow, and they leave dirt in these snow tunnels."

If all this rodent talk has you now thinking about woodchucks and other woodland creatures, know that groundhogs have plenty of nicknames, including "whistle-pig" and "woodchuck," while the only nicknames for gophers appear to be bitter monikers coined by Wisconsin Badgers fans.

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 Christmas Island’s Annual Crab Migration on Google Street View
Google
Google

Every year, the 45 million or so red crabs on the remote Australian territory of Christmas Island migrate en masse from their forest burrows down to the ocean to mate, and so the female crabs can release their eggs into the sea to hatch. The migration starts during the fall, and the number of crabs on the beach often peaks in December. This year, you don’t have to be on Christmas Island to witness the spectacular crustacean event, as New Atlas reports. You can see it on Google Street View.

Watching the sheer density of crabs scuttling across roads, boardwalks, and beaches is a rare visual treat. According to the Google blog, this year’s crabtacular finale is forecasted for December 16, and Parks Australia crab expert Alasdair Grigg will be there with the Street View Trekker to capture it. That is likely to be the day when crab populations on the beaches will be at their peak, giving you the best view of the action.

Crabs scuttle across the forest floor while a man with a Google Street View Trekker walks behind them.
Google

Google Street View is already a repository for a number of armchair travel experiences. You can digitally explore remote locations in Antarctica, recreations of ancient cities, and even the International Space Station. You can essentially see the whole world without ever logging off your computer.

Sadly, because Street View isn’t live, you won’t be able to see the migration as it happens. The image collection won’t be available until sometime in early 2018. But it’ll be worth the wait, we promise. For a sneak preview, watch Parks Australia’s video of the 2012 event here.

[h/t New Atlas]

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