How butterflies navigate using Earth's magnetic field

Washington, January 26 (ANI): Neurobiologists at the University of Massachusetts Medical School (UMMS) in US have linked two related photoreceptor proteins found in butterflies to animal navigation using the Earth's magnetic field.

This research builds on prior investigation into the biological mechanisms through which monarch butterflies are able to migrate up to 2,000 miles from eastern North America to a particular forest in Mexico each year.

The research team used fruit flies engineered to lack their own Cryptochrome (Cry1) molecule, a UV/blue-light photoreceptor already known to be involved in the insects' light-dependent magnetic sense.

By inserting into those deficient flies butterfly Cry1, a homolog of the fly protein, or the related butterfly protein Cry2, the researchers found that either form can restore the flies' magnetic sense in a light-dependent manner, illustrating a role for both Cry types in magnetoreception.

"Because the butterfly Cry2 protein is closely related to the one in vertebrates, like that found in birds which use the Earth's magnetic field to aid migration, the finding provides the first genetic evidence that a vertebrate-like Cry can function as a magnetoreceptor," said Dr. Reppert.

An interesting feature of the team's work disproved a widely held view about how these proteins can chemically sense a magnetic field.

"These findings suggest that there is an unknown photochemical mechanism that the Crys use instead, one that we are hotly pursuing," said Dr. Robert Gegear, research assistant professor of neurobiology.

One of the most exciting aspects of the work was showing that each of the two forms of butterfly Cry have the molecular capability to sense magnetic fields.

Reppert's group is now developing behavioral assays to show that monarchs can actually use geomagnetic fields during their spectacular fall migration.

"We believe we are on the trail of an important directional cue for migrating monarchs, in addition to their well-defined use of a sun compass," said Reppert. (ANI)