Monarka Biological Butterfly Watch

2003/05/23 Elhuyar Zientzia

• Biologia

Before beginning the winter, monarch butterflies leave the north of the United States and Canada and head towards the Mexican jungles to spend the winter and reproduce in spring. The cycle of four thousand kilometers of travel is completed every four or five generations, that is, the butterflies heading towards Mexico are heading towards an unknown place, but are not lost on the road.

The researchers are almost convinced that they use the sun to know the direction, but they do not know how they adjust each day that direction as they change the position of the sun. They believe the secret is in the genes that regulate the biological clock. In fact, in butterflies they have detected a gene that is expressed more or less depending on sunlight. As proof of the hypothesis, several monarch butterflies have been introduced in flight simulators designed specifically.

Inside they have played with light/dark cycles to analyze the behavior of butterflies under different cycles and the results have been striking. Those who were under the solar cycle of autumn, when they left the simulator, left towards the southwest, towards Mexico. Those who were under shorter solar cycles were heading to the southeast and those who remained under light for all the time directly toward the sun.

Photo: David Weaver/Science