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Microsoft revealed on Wednesday that it gained a court order that compelled VeriSign, the .com registry, to remove 277 ".com" names from its rolls, effectively cutting off communication between the Waledac's controllers and their infected machines. The legal action is unprecedented at the domain name level, said Andre' M. DiMino, co-founder of The Shadowserver Foundation, a group that tracks botnets and helped take down Waledac. In June 2009, a federal court ordered the shutdown of 3FN, a rogue ISP supplying connectivity to botnets such as Pushdo and Mega-D, but this appears to be the first major action at the domain-name level. "It's definitely pretty groundbreaking," DiMino said. "To disable and disrupt a botnet at this level is really pulling the weed out by the root." But behind the scenes, Microsoft's legal action was just one component of a synchronized campaign to bring down Waledac. Last year, researchers with the University of Mannheim in Germany and Technical University Vienna in Austria published a research paper showing how it was possible to infiltrate and control the Waledec botnet. They had studied Waledac's complicated peer-to-peer communication mechanism. Microsoft -- which was annoyed by Waledec due to its spamming of Hotmail accounts -- contacted those researchers about two weeks ago to see if they could perform their attack for real, according one of the University of Mannheim researchers, who did not want to be identified. "They asked me if there was also a way besides taking down those domains of redirecting the command-and-control traffic," said the Mannheim researcher. Waledac distributes instructions through command-and-control servers that work with a peer-to-peer system. Led by a researcher who did his bachelor thesis on Waledac, the action began early this week. "This was more or less an aggressive form of what we did before," the Mannheim researcher said. "We disrupted the peer-to-peer layer to redirect traffic not to botmaster servers but to our servers." At the same time, Microsoft's legal efforts brought down domain names that were used to send new instructions to drones. The result has been dramatic: Up to 90 percent of the infected machines, which amount to at least 60,000 computers, are now controlled by researchers, half of which are in the U.S. and Europe and the rest scattered around the globe.

Known as 'polyandry' among scientists, the phenomenon of females having multiple mates is shared across most animal species, from insects to mammals. This study suggests that polyandry reduces the risk of populations becoming extinct because of all-female broods being born. This can sometimes occur as a result of a sex-ratio distortion (SR) chromosome, which results in all of the Y chromosome 'male' sperm being killed before fertilisation. The all-female offspring will carry the SR chromosome, which will be passed on to their sons in turn resulting in more all-female broods. Eventually there will be no males and the population will die out. For this study, the scientists worked with the fruitfly Drosophila pseudoobscura. They gave some populations the opportunity to mate naturally, meaning that the females had multiple partners. The others were restricted to having one mate each. They bred several generations of these populations, so they could see how each fared over time. Over fifteen generations, five of the twelve populations that had been monogamous became extinct as a result of males dying out. The SR chromosome was far less prevalent in the populations in which females had the opportunity to have multiple mates and none of these populations became extinct. The study shows how having multiple mates can suppress the spread of the SR chromosome, making all-female broods a rarity. This is because males that carry the SR chromosome produce only half as many sperm as normal males. When a female mates with multiple males, their sperm will compete to fertilise her eggs. The few sperm produced by males carrying the SR chromosome are out-competed by the sperm from normal males, and the SR chromosome cannot spread.