1 Tahrcountry Musings: Amazing compass sense of Moths

Sunday, April 06, 2008

Amazing compass sense of Moths

Migrating moths have always puzzled scientists. They had no clue about how the moths avoid being blown away from their seasonal breeding grounds by gusty winds. Recently an international team led by entomologist Jason Chapman of Rothamsted Research in Harpenden, U.K., tracked swarms of silver Y moths (Autographa gamma) leaving the United Kingdom for their winter breeding site in the Mediterranean. The insects have a penchant for cruising on faster, high-altitude air currents that mainly occur at night. The scientists found that during most of the mass migrations, a significant proportion of the moths pointed their bodies in the same direction. When the wind direction was off by more than 20 degrees, the moths changed their flight angle to stay on course. This clearly demonstrates a compass sense in the nocturnal migrating insects. Dragonflies and butterflies were already known to change their flight paths to compensate for wind drift. Full report appears in the latest issue of Current Biology. Amazing facts. The findings have unexpected spin-offs. The scientists say understanding the moths’ sense of direction could help in predicting future insect migrations, which are likely to increase as global warming makes northern countries more hospitable to pests.

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