1/15/2005

Interplanetary flights and lying flies

I’m jazzed about the successful landing of the Huygens probe on Titan. San Francisco Chronicle science writer David Perlman, covering the event from Darmstadt, Germany, described the early scenes beamed back from the probe: “The black and white images, taken during the descent at 95 miles above the surface, then 10 miles above, and a final one at the surface itself, revealed solid, rough-sided hills with deeply shadowed drainage channels, most likely carved by liquid hydrocarbons flowing down from above; clusters of rough boulders, and what appeared to be a shoreline, possibly fronting a dark lake or perhaps a hydrocarbon sea.” The European Space Agency website downplays expectations that we'll discover life on Titan: “Titan is not a pleasant place for life. It is far too cold for liquid water to exist, and all known forms of life need liquid water. Titan's surface is -180°C. According to one exotic theory, long ago, the impact of a meteorite, for example, might have provided enough heat to liquify water for perhaps a few hundred or thousand years. However, it is unlikely that Titan is a site for life today.” Meanwhile, here on earth, I noticed this item worth a chuckle. Male flies offer females gifts of food in exchange for sex – but sometimes substitute fakes for edible treats. This bait-and-switch tactic may offer tricky males an evolutionary advantage, study author Natasha LeBas of the University of St Andrews in Scotland told New Scientist magazine. Males who hunt for food expose themselves to danger, while those who offer spoof mating gifts take fewer risks in the act of passing on their genes. Spoof gifts worked so long as the ruse was elaborate, UC Davis entomologist Steven Heydon told Animal Planet: "By the time the female finishes unwrapping her gift and discovers that it is empty, the male has mated with her." An article on the Animal Planet website noted that, when it comes to gifts, size matters: “The researchers also found a link between the size and quality of a gift and the duration of copulation. Impressively large, real food gifts presented before mating led to the longest copulation periods. Smaller, real gifts were next in line, followed by the big fake token presents and then small, worthless gifts.” Tom Abate

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