The monarch butterflies that migrate from North America to Mexico these days incorporate a 24-hour "clock" in their antennas that helps them stay on their path as the sun changes position during the day, according to a study published today. in Science .
To reach this conclusion, neurobiologist Christine Merlin and her colleagues at the University of Massachusetts School of Medicine surgically removed the antennae of some butterflies and flew them outdoors in a flight simulator. As a result of the operation, the insects lost their normal orientation ability, even though the clock molecules in their brain were still "on time."
Later experiments in which the antennae of the butterflies were covered with an enamel of white or black paint confirmed that these organs incorporate a kind of GPS for orientation directed by the sun . Merlin suggests that other insects that navigate by solar position might use their antennae in a similar way.
