CLOSE
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."

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

nextArticle.image_alt|e
iStock
arrow
Animals
Where Do Birds Get Their Songs?
iStock
iStock

Birds display some of the most impressive vocal abilities in the animal kingdom. They can be heard across great distances, mimic human speech, and even sing using distinct dialects and syntax. The most complex songs take some practice to learn, but as TED-Ed explains, the urge to sing is woven into songbirds' DNA.

Like humans, baby birds learn to communicate from their parents. Adult zebra finches will even speak in the equivalent of "baby talk" when teaching chicks their songs. After hearing the same expressions repeated so many times and trying them out firsthand, the offspring are able to use the same songs as adults.

But nurture isn't the only factor driving this behavior. Even when they grow up without any parents teaching them how to vocalize, birds will start singing on their own. These innate songs are less refined than the ones that are taught, but when they're passed down through multiple generations and shaped over time, they start to sound similar to the learned songs sung by other members of their species.

This suggests that the drive to sing as well as the specific structures of the songs themselves have been ingrained in the animals' genetic code by evolution. You can watch the full story from TED-Ed below, then head over here for a sample of the diverse songs produced by birds.

[h/t TED-Ed]

nextArticle.image_alt|e
NOAA, Wikimedia Commons // Public Domain
arrow
Animals
Watch the First-Ever Footage of a Baby Dumbo Octopus
NOAA, Wikimedia Commons // Public Domain
NOAA, Wikimedia Commons // Public Domain

Dumbo octopuses are named for the elephant-ear-like fins they use to navigate the deep sea, but until recently, when and how they developed those floppy appendages were a mystery. Now, for the first time, researchers have caught a newborn Dumbo octopus on tape. As reported in the journal Current Biology, they discovered that the creatures are equipped with the fins from the moment they hatch.

Study co-author Tim Shank, a researcher at the Woods Hole Oceanographic Institution in Massachusetts, spotted the octopus in 2005. During a research expedition in the North Atlantic, one of the remotely operated vehicles he was working with collected several coral branches with something strange attached to them. It looked like a bunch of sandy-colored golf balls at first, but then he realized it was an egg sac.

He and his fellow researchers eventually classified the hatchling that emerged as a member of the genus Grimpoteuthis. In other words, it was a Dumbo octopus, though they couldn't determine the exact species. But you wouldn't need a biology degree to spot its resemblance to Disney's famous elephant, as you can see in the video below.

The octopus hatched with a set of functional fins that allowed it to swim around and hunt right away, and an MRI scan revealed fully-developed internal organs and a complex nervous system. As the researchers wrote in their study, Dumbo octopuses enter the world as "competent juveniles" ready to jump straight into adult life.

Grimpoteuthis spends its life in the deep ocean, which makes it difficult to study. Scientists hope the newly-reported findings will make it easier to identify Grimpoteuthis eggs and hatchlings for future research.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios