Monarch butterflies down again this year as decline continues, says Texas A&M expert

March 21, 2012

COLLEGE STATION, March 21, 2012 - Unlike their colorful wings, the future of Monarch butterflies may not be too bright and their numbers are expected to be alarmingly down again this year, says a Texas A&M University researcher.

Craig Wilson, a senior research associate in the Center for Mathematics and Science Education and a long-time butterfly enthusiast, says reports by the World Wildlife Fund, private donors and Mexico's Michoacan state show that Monarch numbers will be down almost 30 percent in 2012 as they make their annual trek from their breeding grounds in Mexico and move across Texas.

The figures show an alarming decades-long decline in their numbers, Wilson says, adding that it is best "that we take the long view rather than yearly cycles.

"The latest information shows that Monarchs will be down from 25 to 30 percent this year, and that has been part of a disturbing trend the last few years," Wilson notes.

"Last year's severe drought and fires in the region no doubt played a part, resulting in less nectar for the Monarchs as they migrated south. But estimates show that each year, millions of acres of land are being lost that would support Monarchs, either by farmers converting dormant land for crop use - mainly to herbicide tolerant corn and soybeans - or the overuse of herbicides and mowing. Milkweed is the key plant because it's the only plant where the female will lay her eggs."

The loss of such lands is a critical factor in the Monarchs' survival, Wilson explains.

"Chip Taylor, who is the director of Monarch Watch at the University of Kansas, estimates that 100 million acres of land have already been lost that previously supported Monarchs," Wilson notes.

Most of the Monarch reserves are in the Mexican state of Michoacan. It's an area where Monarchs spend the winter and mate before heading north, Wilson points out.

In the spring, the butterflies leave Mexico and across Texas, and Wilson has noticed both eggs and young Monarch caterpillars feeding on milkweed in the Monarch Waystation, a butterfly garden outside his office. The adults will fly various routes through Texas, with the fourth generation eventually arriving in Canada.

This year, according to the Texas Monarch Watch, Monarchs covered about 7.14 acres of forest in their Mexican breeding grounds compared to 9.9 acres last year, and it shows a continued long-term downward trend in Monarch population since official surveys began in 1994.

Wilson says there has to be a national effort to save Monarchs or their declining numbers will reach the critical stage.

"We need a national priority of planting milkweed to assure there will be Monarchs in the future," he says. "If we could get several states to collaborate, we might be able to promote a program where the north-south interstates were planted with milkweed, such as Lady Bird Johnson's program to plant native seeds along Texas highways 35-40 years ago. This would provide a 'feeding' corridor right up to Canada for the Monarchs."
-end-
Wilson says there are several websites to monitor Monarchs. They include http://www.texasento.net/dplex.htm, also http://www.learner.org/jnorth, and http://www.monarchwatch.org.

Media contact: Keith Randall, News & Information Services, at (979) 845-4644 or keith-randall@tamu.edu; or Craig Wilson at (979) 260-9442 or cell phone at (512) 636-9031 or cwilson@science.tamu.edu

For more news about Texas A&M University, go to http://tamutimes.tamu.edu.

Follow us on Twitter at http://twitter.com/tamu.

Texas A&M University

Related Monarch Butterflies Articles from Brightsurf:

Two centuries of Monarch butterflies show evolution of wing length
North America's beloved Monarch butterflies are known for their annual, multi-generation migrations in which individual insects can fly for thousands of miles.

Native milkweed cultivars planted by the public can support monarch butterflies and bees
Millions of people plant pollinator gardens in an effort to provide monarch butterflies with food along their annual migration route from overwintering sites in the highland forests of central Mexico to summer breeding grounds in the United States and southern Canada.

New study on migration success reinforces need for monarch butterfly milkweed habitat
A recently published study presents evidence that the migration success of monarchs hasn't declined in recent years and thus cannot explain the steep decline in the monarch population over the last few decades.

Milkweed, only food source for monarch caterpillars, ubiquitously contaminated
New evidence identifies 64 pesticide residues in milkweed, the main food for monarch butterflies in the west.

Human handling stresses young monarch butterflies
People handle monarch butterflies. A lot. Every year thousands of monarch butterflies are caught, tagged and released during their fall migration by citizen scientists helping to track their movements.

What do soap bubbles and butterflies have in common?
A unique butterfly breeding experiment gave UC Berkeley researchers an opportunity to study the physical and genetic changes underlying the evolution of structural color, responsible for butterflies' iridescent purples, blues and greens.

Bacteria get free lunch with butterflies and dragonflies
Recent work from Deepa Agashe's group at NCBS has found that unlike other insects, neither butterflies nor dragonflies seem to have evolved strong mutualisms with their bacterial guests.

Team finds link between vitamin A and brain response in Monarch butterflies
Biologists at Texas A&M University are making strides in understanding biological clock function in several model organisms and translating these studies into broader implications for human health.

CRISPRed fruit flies mimic monarch butterfly -- and could make you puke
Monarch butterflies and a few other insects evolved essentially the same genetic mutations allowing them to eat toxic milkweed without getting sick.

Monarch butterflies rely on temperature-sensitive internal timer while overwintering
The fact that millions of North American monarch butterflies fly thousands of miles each fall and somehow manage to find the same overwintering sites in central Mexican forests and along the California coast, year after year, is pretty mind-blowing.

Read More: Monarch Butterflies News and Monarch Butterflies Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.