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Female Butterflies Have A Second Stomach—Inside Their Vaginas

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The animal kingdom is full of examples that illustrate just how tough the mating game can be. But there is perhaps no better example of this than the female butterfly, which has evolved an entirely distinct organ to protect her own interests—in response to a similarly selfish evolution by the males, naturally.

Female butterflies have notoriously complex and convoluted reproductive systems, which include a relatively mysterious organ known as the bursa copulatrix. Recent research by University of Pittsburgh graduate student Melissa Plakke helped to illuminate what's going on in there, but to understand it you first have to understand the harsh game of strategy that is butterfly sex.

To help further their own lines, male butterflies—like many other insects—have evolved to deliver their sperm inside a package called a spermatophore. Spermatophores contain proteins to help improve their sperm's chances by giving sperm a speed boost, or by plugging a female's vagina so other males can't copulate with her.

This could potentially be bad news for the female, who would like to give herself as many chances as possible to reproduce and pass on her genes—which is why female butterflies have evolved the ability to dismantle those proteins and use them to maintain their own bodies and eggs. Because this is an evolutionary arms race of sorts, the outer shell of the male's spermatophore is surprisingly tough. 

This back and forth is where the bursa copulatrix comes in. Scientists initially thought the organ might be "digesting" the tough spermatophore shell and trapping useful proteins, but they weren't sure. Plakke's research studied the interior of the bursa copulatrix in cabbage white butterflies, using specimens that were sexually active and some that weren't. She and her team found nine different enzymes in the bursa that break down proteins—meaning the bursa copulatrix is "eating" the male's proteins like a second stomach. Because adult butterflies don't actually consume other proteins, this organ has been compared to the section of the caterpillar gut responsible for digesting protein—but it's just one-twentieth of the size, which means the bursa copulatrix is just as, if not more, digestively powerful.  

[h/t Discover]

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Animals
Where Do Birds Get Their Songs?
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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]

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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.

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