Tags: science & technology

[ ghostbusters: egon ]

Penis Fencing

There are a large number of fascinating creatures that live in coral reefs, leaf litter, and the ocean floor. One animal that inhabits all three ecosystems is the flatworm (phylum Platyhelminthes), and in particular the non-parasitic Turbellaria. The larger members of this sub-division are often brilliantly-hued and share a few other special characteristics. All flatworms lack a body cavity and specialized organs for the respiratory and circulatory systems, and in addition to this they use ocelli to sense light and dark rather than 'true' eyes, and expel waste material through their mouth, since many also lack an anus.

Of course, the trait that catches most people's attention is in relation to their reproductive habits. I first caught mention of penis fencing in Tim Birkhead's Promiscuity: An Evolutionary History of Sperm Competition but the behavior is discussed, not surprisingly, in a number of other sources. Flatworms are hermaphrodites - each animal possesses male and female reproductive cells - and obtain a much greater evolutionary pay-off by playing the male role during copulation. Pregnancy is such an energy-intensive endeavor that each member of a mating pair would prefer to inject their sperm and be done with it. As a result, mating flatworms each try to impregnate the other without falling victim to the same fate themselves; the circling and jousting that often takes place during these sessions is what gave rise to the term 'penis fencing'.

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[ bee's knees ]

Ants in Korea

I caught an interesting article from BBC Earth News last night that involves a study of 'super-colonies' among Linepithema humile (Argentine ants). The general idea behind the report is that transplanted ants from the Paraná River basin have set up massive-sized colonies stretching along the coasts of the Mediterranean (6,000km), southern California (900km), and western Japan. These ants all share a common genetic make-up, which means that groups from neighboring sites do not attack one another as they would within other ant populations. In particular, the chemical make-up of hydrocarbons on the ants' cuticles seems to hold the key in recognizing friend from foe.

According to the BBC piece, representatives from all of the super-colonies "rubbed antennae with one another and never became aggressive or tried to avoid one another". Meanwhile, those from 'smaller' colonies (in Catalonia, Spain and Kobe, Japan) were very aggressive toward their colonial brethren -- the ants taken from the super-colonies of the Mediterranean and western Japan. And what does "very aggressive" mean? Well, the San Diego Union-Tribune has a piece on Argentine ants that mentions research conducted by David Holway, Andrew V. Suarez, et al. and includes the following:

At territorial boundaries where ants of different colonies confront each other, full-fledged battles are frequent, murderous and epic on a miniature scale.

During one six-month study, for example, Thomas [Melissa Thomas, a University of California-San Diego postdoctoral fellow involved with the study] estimated that border skirmishes around one of the smaller colonies at Lake Hodges resulted in the deaths of at least 15 million workers.

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[ moche condor ]

I'll bring the Hershey's if you guys pick up some Corona ...

One of the gifts my parents always gave me for Christmas was a year-long subscription to a magazine of my choice. During the first half of elementary school they bought me subscriptions to Ranger Rick or National Geographic World (which apparently hasn't existed for several years now), while my interests in sixth grade prompted them to sign up for Discover magazine. My transition from elementary to middle school was accompanied by further issues of Discover, and it continued to be my magazine of choice into high school. I still have the old issues stored at my parents' house.

I recently came across an article from Discover's online site that I found interesting. It's pretty short, so I'll include it here in its entirety - including the somewhat humorous image that went with the article.

Getting Drunk on Chocolate in 1100 B.C.
Ancient pottery shows traces of a chemical found in cacao.
by Clara Moskowitz
published online April 7, 2008

Not only were the first chocoholics tinkering with cacao around 1100 B.C.—500 years earlier than previously thought—but they might have been doing so to get a tipsy buzz. A recent chemical analysis of 3,000-year-old pottery shards in northern Honduras turned up traces of theobromine (its name means “food of the gods”), a chemical that is found in cacao. The discovery is the oldest evidence of cacao manipulation. The analyzed ves­sel had a narrow spout, and the researchers speculate that the locals were imbibing a winelike drink made by fermenting the pulp that surrounds the seeds of the cacao plant. In contrast, the nonalcoholic concoction favored by Aztecs some 2,000 years later was prepared in wide-lipped jugs, and the liquid was poured back and forth to create froth.

Beer enthusiasts can look forward to a loose re-creation of the ancient brew sometime this year. Dogfish Head Craft Brewery in Delaware is producing a drink based on the original recipe, with the help of biomolecular archaeologist Patrick McGovern of the University of Pennsylvania Museum, who aided in the Honduran study. “We tweaked the recipe, adding hops for the modern palate,” says Sam Calagione, Dogfish Head founder and president, “but I still think of it as a liquid time capsule.”

Hey kutay, are you interested in trying this stuff and reporting back on how it tastes?
[ ghostbusters: egon ]

limax redii

Because I don't see why I should be the only person who knows this:

Slugs and their shelled cousins, snails, are hermaphrodites, and copulation usually involves the slimy intertwining of two individuals and the simultaneous insertion of penises. In some slugs the penises themselves do the intertwining and sperm exchange occurs outside their bodies. Courtship in the common European garden slug, aptly named Limax maximus, involves two animals following each other in a clockwise manner on a vertical surface. On making contact they produce a mucus anchor rope from which they suspend themselves. As the entwined animals dangle in space they each evert and entwine their gigantic penises which far below their owners exchange sperm at their tips. In the slug Limax redii the penis is 85cm long - seven times the length of its owner's body. We have no idea whether the slug's giant penis and the unusual pattern of copulation have evolved in response to sperm competition or any other kind of sexual conflict. But we do know that for some species they can be a cause of the worst kind of sexual conflict. Their entwined penises frequently become knotted during copulation and the only way individuals can release themselves is to bite off their own penis at its base! It is not clear whether both individuals have to do this to ensure freedom. If not, there is presumably protracted negotiation about who will sacrifice his masculinity. Thereafter, those individuals that have lost their penis in this way operate only as females.

- Tim Birkhead, Promiscuity pp 98-99