How migrating butterflies use body clocks to find their way
The spectacular migration of the monarch butterfly, which covers a 2,000-mile round trip in a year, uses an inbuilt precision clock that enables the insect to use the sun as a compass, a study has found.
An internal biological clock that times the 24-hour cycle of night and day allows the monarch butterfly to calculate its direction of flight when migrating either north or south, depending on the time of the year, scientists have discovered.
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 feat for such as small creature. As the monarchs fly north in spring they breed several times during their summer journey. Four or five generations later, their offspring make the long journey home again, often landing in the same Mexican valley and even on the same tree that their great, great grandparents left the previous winter.
Scientists have known for years that the monarchs use the sun as a compass to guide them on their journey, and as a calendar for telling them when to begin the return journey to Mexico. But a compass based on the sun's moving position in the sky would not work unless the insects also have an accurate clock to tell them the time of day.
No one had been able to locate this internal timepiece, until now. 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.
Professor Reppert said that 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, Professor Reppert said. "This is a very interesting realignment of how one thinks about insect-clock models. There was no reason to suspect the butterfly clock would be different," he said.
"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," he said. "We have still to understand how the tiny brain of the monarch butterfly, which is no bigger than the head of a ballpoint pen, can arrange information about time and space that leads it to carry out the appropriate flight behaviour," Professor Reppert told the online journal Public Library of Science.
New UK station Russia Today gives a very bizarre view of Britain
By performing as African Americans or Indians, white people get to play act a kind of 'imaginary liberation', writes Michael Mark Cohen
New essay by JK Rowling went live on Pottermore site this morning
Top Gear presenter is no stranger to foot-in-mouth controversy
Video: Watch the amazing moment a beluga whale gives birth in Chinese aquarium
Global warming ‘will make our winters colder’
Here are the top 10 trees nominated for 'tree of the year'
Ladybirds are invading our houses this autumn, often in their thousands. What's going on?
Humanity's 'inexorable' population growth is so rapid that even a global catastrophe would not stop it
- 1 Canadian actor punched in face after 'Islamophobia' experiment goes wrong in wake of Ottawa shooting
- 2 Topshop at centre of row over body image as 'shocking' skinny mannequin photo goes viral
- 3 Top Gear presenter Jeremy Clarkson criticised for beer tweet
- 4 The bubble bursts for Sodastream
- 5 If you think Russell Brand’s new book is confused, you should read what his critics have to say about it
Pope Francis declares evolution and Big Bang theory are real and God is not 'a magician with a magic wand'
Huge surge in Ukip support after EU funding row, according to new poll
Ukip ‘exploiting grooming scandal’ to secure party’s first police chief
Nigel Farage: 'There’s nothing wrong with white people blacking up'
Maureen Lipman says 'she can't vote Labour while Ed Miliband is leader'
Muslims, immigration and teenage pregnancy: British people are ignorant about almost everything
£40000 - £65000 per annum + bonus + benefits + OT: Ampersand Consulting LLP: M...
£22800 - £33600 per annum: Randstad Education Manchester Secondary: The JobAt ...
£22800 - £33600 per annum: Randstad Education Manchester Secondary: Calling al...
£100 - £125 per day: Randstad Education Chelmsford: EYFS Teachers - East Essex...