Booming Monarch Butterfly Population Faces Obstacles, Expert Says

September 6, 2006

Monarch butterfly followers can expect an unusually large population of the winged insects this season they make their way to their winter home in Mexico, but a University of Kansas professor says there may be trouble ahead.

Just-right weather conditions during the spring trip out of Mexico contributed to this year’s expanded population, said Orley “Chip” Taylor, professor of ecology and evolutionary biology and director of the Monarch Watch program at KU.

“The temperatures were perfect, the moisture conditions were perfect. It was neither too hot, nor too dry, nor too rainy or too windy,” he said.

The returning butterflies produced a large number of offspring, who reproduced even more as they traveled north.

“So every step of the way this year has been favorable for the butterflies, and that doesn’t happen often,” Taylor said.

Taylor said this year’s population is probably the biggest Monarch watchers have seen in 10 years. He is already receiving reports from long-time monarch observers who say they have never seen so many.

But a difficult road lies ahead for the monarch butterflies, who travel more than 2,000 miles from Canada to Mexico. This summer’s extreme temperatures and lack of rain have left dry conditions in Texas and some of southern Oklahoma and may diminish the population the farther south the butterflies go.

“It means there aren’t going to be any flowers. It means there isn’t going to be any water, and there isn’t going to be any nectar,” Taylor said.

The butterflies use nectar to acquire carbohydrates and water to fuel the long flight to Mexico. They convert carbohydrates into lipids, or fats, to store for the rest of their trip and the winter in Mexico.

“They’re going to be going through what looks like about 1,000 miles of really dry habitat,” Taylor said. “So unless there is rainfall in this region between now and October, the death toll for these butterflies going through Texas is going to be pretty severe.”

That death toll could have an impact on next year’s population.

The butterflies have already begun making their way to Kansas. Monarch watchers, Taylor said, should begin seeing the butterflies Sept. 8-11. They’ll peak about Sept. 23 before gradually fading out in early October.

Children can learn more about the butterflies during Monarch Watch’s annual Open House from 9 a.m. to 4 p.m. Saturday, Sept. 9, in Foley Hall on KU’s west campus. Some children will leave with a caterpillar or chrysalis, which is a monarch butterfly pupa, to take home and watch grow.

“We can capture the imagination of a lot of children and use this information to improve secondary education in primary and secondary schools,” Taylor said.

The annual tagging event will be from 7:30 to 11:30 a.m. Saturday, Sept. 16, at the Baker-Haskell Wetlands.

Source: University of Kansas