Category: Sex and reproduction

Cuttlefish woos female and dupes male with split-personality skin

By Ed Yong | July 3, 2012 7:00 pm

Imagine trying to talk to two people at the same time. I don’t mean just talking to one and then the other – I mean simultaneously saying different things to both of them. And in one of those conversations, you’re pretending to be someone of the opposite sex. That’s exactly the exchange that Culum Brown from Macquarie University has witnessed off the east coast of Australia.

The speakers were mourning cuttlefish – relatives of octopus and squid, and masters of camouflage. By rapidly expanding and contracting sacs of pigment in their skin, cuttlefish can turn their entire bodies into living video displays. Colours appear and vanish. Mesmeric waves cascade across their flanks. They can even produce different patterns on the two halves of their bodies.

Brown saw a male cuttlefish swimming between a female and a rival male, and displaying different messages to both of them. On his left half, the one the female could see, he flashed zebra-stripe courtship colours to advertise his interest. But on his right half, facing the rival male, he flashed the mottled colours of a female. As far as the competitor was concerned, he was swimming next to two females, oblivious to the act of cross-dressing/seduction going on right next to him. The cheater, meanwhile, prospers.

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Male spider castrates himself and gets more stamina

By Ed Yong | June 12, 2012 7:00 pm

To become both a lover and a fighter, the male spider Nephilengys malabarensis snaps off his penis inside his partner while they have sex. He becomes better at fending off other males who try to mate with her, because his now-lightened body can fight for longer without tiring. And while he’s playing the guardian, his detached genitals can continue pumping sperm into the female. Through self-castration, he gets more stamina, and he gets more stamina.

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Bumphead parrotfish use bumpy heads to bump heads [VIDEO]

By Ed Yong | June 8, 2012 9:00 am

Some animals are poorly named. The flying lemur doesn’t fly and isn’t a lemur. The mantis shrimp isn’t a mantis or a shrimp. The killdeer couldn’t. But the giant bumphead parrotfish… it’s a giant fish with a beak like a parrot and a bump on its head. Nice one, biologists. You can have a point for that.

The giant bumphead parrotfish (Bolbometopon muricatum) is the biggest herbivorous fish in coral reefs. It can reach 1.5 metres in length and weigh over 75 kilograms, and it has a distinctively bulbous forehead. Why? There are rumours that it uses its head to ram corals, breaking them up into smaller and easier-to-eat chunks.

But Roldan Munoz from the National Oceanic and Atmospheric Administration has discovered one definite use for the bump: headbutting rivals. Check out the video below – it all kicks off at the ten-second mark, and I love the “Whoooah” that follows.

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Will we ever clone a mammoth?

By Ed Yong | June 6, 2012 9:00 am

Here’s the eighth piece from my BBC column

Tens of thousands of years ago, woolly mammoths roamed the northern hemisphere. These giant beasts may now be extinct, but some of their bodies still remain in the frozen Arctic wilderness. Several dozen such carcasses have now been found, and some are in extremely good condition. Scientists have used these remains to discover much about how the mammoth lived and died, and even to sequence most of its genome. But can they also bring the animal back from the dead? Will the woolly mammoth walk again?

Akira Iritani certainly seems to think so. The 84-year-old reproductive biologist has been trying to clone a mammoth for at least a decade, with a team of Japanese and Russian scientists. They have tried to use tissues from several frozen Siberian specimens including, most recently, a well-preserved thighbone. Last year, Iritani told reporters, “I think we have a reasonable chance of success and a healthy mammoth could be born in four or five years.”

A few months ago, a second team led by Korean scientist Hwang Woo Suk also expressed interest in cloning a mammoth. While Iritani comes with impressive credentials, Hwang’s resume is less reassuring. He is perhaps best known for faking experiments in which he claimed to have cloned the first human embryo and produced stem cells from it. The fact that he has confessed to buying mammoth samples from the Russian mafia does not help to instil confidence.

Regardless of their pedigree, both teams have their work cut out. Any attempt to resurrect the mammoth faces an elephantine gauntlet of challenges, including the DNA-shattering effects of frost and time, and the rather unhelpful reproductive tract of the eventual surrogate parent—the elephant.

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Insects that skate on the ocean benefit from plastic junk

By Ed Yong | May 8, 2012 7:00 pm

Imagine a world of two dimensions, a world with no up or down… just across. No climbing, falling, jumping, or ducking… just shimmying and sidling. Welcome to the world of the sea skater.

Sea skaters, or ocean striders, are small bugs. They’re relatives of the pond skaters or water striders that zip spread-eagled across the surface of ponds and lakes. Except they skate over the open ocean, eating plankton at the surface. “They skate through storms and wind and waves,” says Miriam Goldstein from the University of California San Diego and the Deep Sea News blog. “They even have a little ‘life jacket’ – the hairs on their body trap air so if they get sunk by a wave, they pop back up. They’re amazing!”

There are only five species of sea skaters, all belonging to the Halobates group. Of all the millions of insect species, these five are the only ones to live out at sea. Now, Goldstein has discovered that one sea skater Halobates sericeus actually benefits from what most people would regard as an ecological disaster – the circling mass of plastic and debris known as the Great Pacific Garbage Patch.

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Male water striders evolved antennae to grab females by the eyes

By Ed Yong | May 3, 2012 2:00 pm

The worst sex you have ever had pales in comparison to what female water striders have to put up with. Put it this way: you have never been held down by your eyes.

As the female skates over the surface of ponds and lakes, males will try to force themselves upon her. She resists by struggling vigorously. But in some species, males can avoid being thrown off with antennae that have evolved into antler-shaped restraints. They bend in on themselves and are loaded with an array of prongs and spikes that perfectly fit to the shape of a female’s head.

Locke Rowe from the University of Toronto has been studying water striders for almost 20 years. In many species, males have evolved structures that give them an edge in their indelicate liaisons with females. “But the traits I studied before were rather simple – a spine here or there,” says Rowe. The subject of his latest study, a species called Rheumatobates rileyi – is… well, the opposite of simple.

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Spotted bowerbirds get more sex by cultivating fruit

By Ed Yong | April 23, 2012 12:00 pm

The sexual success of the male spotted bowerbird depends on his gardening skills. In his patch of forest, where he displays to mates, he cultivates a small fruiting shrub called the ‘bush tomato’, with purple flowers and green fruit.

It’s not clear if his actions are deliberate or inadvertent, but it is clear that he doesn’t eat the fruit. The plant is there to provide him with decorations, to make his boudoir that much more enticing to a female. Aside from humans, the spotted bowerbird is the only other animal that grows a plant for purposes other than food.

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Kangaroos have three vaginas

By Ed Yong | April 17, 2012 11:20 am

We interrupt your regularly scheduled news programming to bring you this wonderful piece of trivia about kangaroo genitals.

Regular readers will know of my love for Inside Nature’s Giants, the British documentary where anatomists cut up large animals to examine how their bodies work and evolved. It’s a truly incredible show, combining unbridled joy at the natural world, drama, and solid educational value.

So far, it has brought us the horrifying throat of a leatherback turtle, the mysterious bloodsweat of a hippo, and the exploding insides of a beached whale. But this week’s episode may have topped all of that with the triple vaginas of the female kangaroo. The diagram above (an annotated screengrab from the show) explains the complicated plumbing.

This set-up is shared by all marsupials – the group of mammals that raise their young in pouches. Koalas, wombats and Tasmanian devils all share the three-vagina structure. The side ones carry sperm to the two uteruses (and males marsupials often have two-pronged penises), while the middle vagina sends the joey down to the outside world.

Note that the ureters, which carry urine from the kidneys to the bladder, pass through the gaps between the three tubes. In placental mammals, like us, the ureters develop in a different way, and don’t go through the reproductive system. As we develop, the precursors to the reproductive tubes eventually fuse into a single vagina. In marsupials, this can’t happen.

The programme also suggested that this might explain why marsupial embryos are born at such a premature stage of development. A kangaroo’s joey is about the size of a jellybean when it leaves the vagina, and it must endure an arduous crawl into the pouch. It’s possible that with such a narrow tube to go down, it couldn’t get any bigger before its birth.

With its complicated reproductive set-up, a female kangaroo can be perpetually pregnant. While one joey is developing inside the pouch, another embryo is held in reserve in a uterus, waiting for its sibling to grow up and leave. Indeed, a mother kangaroo can nourish three separate youngsters at a time – an older joey that has left the pouch, a young one developing inside it, and an embryo still waiting to be born.

Mind-controlling virus forces parasitic wasp to put all its eggs in one basket

By Ed Yong | April 10, 2012 9:00 am

Leptopilina boulardi by Alexander Wild

In a French meadow, a creature that specialises in corrupting the bodies of other animals is getting a taste of its own medicine.

Leptopilina boulardi is a wasp that lays its eggs in fly maggots. When the wasp grub hatches, it devours its host form the inside out, eventually bursting out of its dead husk. A maggot can only support a single grub, and if two eggs end up in the same host, the grubs will compete with one another until only one survives. As such, the wasps ensure that they implant each target with just one egg. And if they find a maggot that has already been parasitized by another L.boulardi, they usually stay away.

Usually, but not always.

L.boulardi is sometimes infected by a virus called LbFV, which stands for L.boulardi filamentous virus. And just as the wasp takes over the body of its maggot target, so the virus commandeers the body of the wasp. It changes her behaviour so that she no longer cares if a maggot is already occupied. She will implant her eggs, even if her target has an existing tenant. After infected wasps are finished, a poor maggot might have up to eleven eggs inside it.

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Sri Lankan safari – green turtles mating

By Ed Yong | February 27, 2012 5:50 pm


turtle_mating_claw
turtle_mating1
turtle_mating2
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[After a brief problem with the slideshows, they should be working again – Ed]

I can’t escape animal sex, even on holiday.

On our Sri Lankan boat trip, it took us an hour or so to find some blue whales. But the first animals we saw were no less spectacular. From a distance, they looked like buoys, gleaming bright and white against the sea. As the boat drew closer, we realised that the light wasn’t reflecting off a man-made object, but the shell of a green turtle.

Then we realised that the light was actually reflecting off the shells of two green turtles. They were mating at the surface.

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