Study reveals how monarch butterflies recolonize northern breeding range

Mar 19, 2012

Each year, millions of monarch butterflies (Danaus plexippus) migrate from overwintering grounds in central Mexico to colonize eastern North America, but just how these delicate creatures manage to reach the northern part of their breeding range in spring has largely remained a mystery.

Monarch ButterflyNew research from the University of Guelph led by Prof. Ryan Norris, Department of , former graduate student Nathan Miller and Environment Canada, reveals how monarchs recolonize the northern reaches of their — information that will help preserve this migratory species threatened by loss of critical food and habitat.

Every year, adult monarchs head north to lay eggs on milkweed plants in the United States. Subsequent generations continue north to reproduce, some eventually reaching southern Canada.

But this amazing migration has been declared "threatened" by the International Union for the Conservation of Nature. Because of milkweed destruction, the monarch butterfly has remained on Canada's list of species of "special concern" since 1997.

Norris said scientists need to learn more about the butterfly's migration to forecast how it will respond to environmental change such as habitat loss.

"It wasn't clear where these individuals were born and how long they lived," he said. "One possibility was that some monarchs that reach places like southern Ontario could have migrated all the way from Mexico."

Miller sampled monarchs from 44 sites across Ontario and the northern states. By analyzing chemical markers called stable isotopes and examining wing wear, the researchers found that about 10 per cent reaching the northern breeding range in the spring come directly from Mexico.

"This is an incredible journey from an animal this size, especially if you consider that these butterflies are little more than eight months old and have travelled thousands of kilometres over their lifetime," Miller said.

Ninety per cent of monarchs sampled by the researchers in the spring were first-generation individuals born en route that year. Surprisingly, most of these monarchs were born in the highly productive region of the central United States, not in the southern states as previously thought.

"Linking these periods of the breeding cycle provides us key information for conservation and identifies highly productive regions that fuel the migration further north," said Norris.

The study appears in the journal PLoS One.

Explore further: India's ancient mammals survived multiple pressures

Provided by University of Guelph

4 /5 (1 vote)
add to favorites email to friend print save as pdf

Related Stories

Research reveals how monarchs fly away home

Jul 26, 2010

Monarch butterflies -- renowned for their lengthy annual migration to and from Mexico -- complete an even more spectacular journey home than previously thought.

Monarchs fly south for the winter

Sep 12, 2005

As many as 300 million monarch butterflies are now flying south from Canada and the northern United States to winter in Mexico and Southern California.

Recommended for you

Scientists tether lionfish to Cayman reefs

1 hour ago

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

India's ancient mammals survived multiple pressures

20 hours ago

Most of the mammals that lived in India 200,000 years ago still roam the subcontinent today, in spite of two ice ages, a volcanic super-eruption and the arrival of people, a study reveals.

User comments : 0

More news stories

Scientists tether lionfish to Cayman reefs

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

Deadly human pathogen Cryptococcus fully sequenced

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

Leeches help save woman's ear after pit bull mauling

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...

Venture investments jump to $9.5B in 1Q

Funding for U.S. startup companies soared 57 percent in the first quarter to a level not seen since 2001, as venture capitalists piled more money into an increasing number of deals, according to a report due out Friday.