'Migrating butterflies use body clocks to find their way'

London, Jan 8 (UNI) An internal biological clock that times the 24-hour cycle of night and day allows the monarch butterfly to calculate its direction of flight while migrating, depending on the time of the year, scientists have discovered.

A study by Steven Reppert, professor of neurobiology at the University of Massachusetts Medical School, has identified the key gene in the monarch butterfly that acts as a biological clock for estimating the 24-hour cycle of the circadian rhythm, the Independent reported.

Professor Reppert said the gene was responsible for a light-sensitive protein called Cryptochrome (CRY) which counts the passing hours of each day, and also communicates the information to the monarch's inbuilt solar compass for the insect to calculate its correct direction of flight.

It is the second CRY gene to be found in insects. The first, CRY1, was discovered in drosophila fruit flies but the monarch's gene is sufficiently different to warrant a distinctive name, CRY2, ''What we have in the butterfly is an astounding clock mechanism, one that is more similar to our own circadian clock and less similar to the clock of a fly,'' Professor Reppert said.

Monarch butterflies are famous for the journey they make each spring from their winter roosting sites in the mountain pine trees of Mexico to as far as the US-Canadian border and back again in autumn- an unparalleled migratory act for such a small creature.

UNI XC ARB BST1126