1
In brief – Research news and discovery WARM springs and wet summers make an outbreak of bubonic plague more likely. The plague is caused by the bacterium Yersinia pestis, which is carried by rodents. Using field data from Kazakhstan spanning 1949 to 1995, a team of researchers led by Nils Stenseth of the University of Oslo, Norway, studied how the number of gerbils infected by plague changes in plague-related deaths in people. “I think that there will be more incidences in animals and therefore more human cases.” Looking back through history, he and his colleagues note that tree-ring measurements suggest similar wet and warm conditions existed during medieval times, when Europe suffered the bubonic plague outbreak known as the Black Death, and around the middle of the 19th century, when another plague pandemic emerged from Asia. with the weather. Both rainy summers and warmer springs increased the bacteria’s prevalence (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0602447103). In particular, the team found a 1 °C rise in spring temperature increases the prevalence of plague in rodents by 60 per cent. Stenseth suggests that global warming may lead to an increase Warming up for a plague outbreak A RAT’S nose knows more about your family than you might think. It seems that rats can identify genetically related humans by similarities in their body odour. Erin Ables and colleagues at the University of Chicago familiarised rats with a human volunteer’s odour, then tested the length of their response to novel odours. The rats investigated odours from people who were genetically related to the volunteer for a shorter time than those who were unrelated. This supports the idea that closely related humans share similar odours, and that the odours have a genetic basis. Previous work suggests that humans can also distinguish between the odours of their relatives and non-relatives. Ables speculates that this ability may help us avoid behaviours such as inbreeding. She presented her work at the Animal Behavior Society meeting last week in Snowbird, Utah. Eau de family FINALLY we have a clue as to why African-American women are more than twice as likely to give birth prematurely as women of European origin. One in eight African- Americans carries a mutated version of a gene that may weaken membranes that support the fetus in the womb, a genetic analysis suggests, compared with just 1 in 25 Americans of European descent. The mutation is of a gene known as SERPINH1, which encodes a protein that stabilises the structural protein collagen, say Jerome Strauss of Virginia Commonwealth University in Richmond, Virginia, and colleagues (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0603676103). Gene is key to premature birth IT’S the speeding bullet of the natural world. The trap-jaw ant snaps shut its mandibles at speeds of 35 to 64 metres per second, over 2000 times faster than the blink of an eye. That makes it the fastest recorded strike in the animal kingdom, say Sheila Patek of the University of California, Berkeley, and colleagues. The previous record holder, the mantis shrimp, punched at a relatively sluggish 23 metres per second. The ant, Odontomachus bauri, cranks its mandibles open with a pair of huge muscles in the head, and holds them cocked with a latch called the clypeus. Releasing the latch unleashes the stored energy, much as a crossbow releases its energy when fired (Proceedings of the National Academy of Sciences, vol 103, p 12787). The ant doesn’t just use its mandibles for biting. If a predator threatens, the ant can strike its jaws on the ground and catapult itself to safety. Vertical jumps can reach over 8 centimetres, and horizontal jumps can throw it almost 40 centimetres. “Interestingly enough, the bite does not hurt,” says Patek. An ant cannot get its jaws around parts of our body as it can around its prey, she says. “The ants simply bounce off when they strike us.” ALEX WILD 18 | NewScientist | 26 August 2006 www.newscientist.com The jaws behind the fastest attack in the world
