Tiny Bluetooth tags are helping researchers uncover new details about the butterflies’ annual journey south across North America

NEED TO KNOW

• Researchers have been tracking monarch butterflies on their annual migration across North America using tiny Bluetooth tags
• A butterfly has been detected across the border in Mexico for the first time, more than five weeks after they began their journey in Utah
• Hundreds of millions of the insects travel nearly 3,000 miles from the north of the U.S. and the south of Canada down to Mexico, where they breed, each fall

The annual monarch butterfly migration is well underway — and some of them are flying with tiny transmitters strapped to their backs.

The U.S. Fish and Wildlife Service’s Center for Pollinator Conservation recently teamed up with Monarch Joint Venture, Three Rivers Park District, the University of Minnesota and the Minnesota Zoo to add tiny Bluetooth tags, weighing just six milligrams each, to a number of the butterflies following the program’s success last year, according to a release from the agency.

Smartphones detect the trackers as the monarchs fly past on their nearly 3,000-mile-long journey south to Mexico, and people can track and log them with the Project Monarch app. Just a few weeks into the migration, one of the monarchs was detected south of the U.S. border for the first time.

The monarch, given the name UB26-UT-06-Chew, began their journey in northeast Utah on Sept. 2, and became the first tagged butterfly to cross the U.S. border, being detected in the Mexican city of Santa Catarina, about 140 miles from Texas, on Oct. 11, per the release.

Another monarch, Mona-MJVFWS-MN26-028, began in northwest Minnesota. The male butterfly flew to the Missouri River in central South Dakota in a direct line, before traveling southwest through Nebraska, Kansas, Colorado, the Oklahoma panhandle and Texas.

He was last detected in the Lone Star State’s Big Bend area, near the border with Mexico, the release stated.

The monarch butterfly’s pattern of migration is the most highly evolved of any species, according to the World Wildlife Fund. Hundreds of millions of the insects fly nearly 3,000 miles in total, from the north of the U.S. and the south of Canada, where they breed, to central Mexico.

At the end of winter, they then fly another 600 miles north back to the U.S., where they lay eggs, before continuing further north again, the charity says.

Monarch butterflies usually only live for between three and five weeks, so it takes multiple generations to complete the migration cycle.

To find out more about monarchs and similar species, the Center for Pollinator Conservation has launched the Tri-National Insect Movement Collaborative along with partners from Canada, Mexico and the U.S., per the release.

Researchers are currently analyzing data from last year’s migration to understand more about migration pathways, successful migrations and roosting — or resting — locations.

Never miss a story — sign up for PEOPLE’s free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from celebrity news to compelling human interest stories.

Tagging is set to continue beyond the fall, to help scientists learn more about how these butterflies behave throughout the year.

It’s hoped that the methods used to track these butterflies might also be used to monitor and learn more about other pollinator species in the future.

#Monarch #Butterflies #Wearing #Tiny #Transmitters #Reveal #Glimpse #Epic #3000Mile #Migration #Mexico