TOLEDO, Ohio (AP) — Nine monarch butterflies released by the Toledo Zoo have been found in central Mexico, supporting the zoo’s belief that its captive-breeding program works.
Monarch researchers have said mass releases may lead to disease and accelerate the butterfly’s decline.
But Ryan Walsh, the zoo’s Wild Toledo coordinator, told The Blade (http://bit.ly/1TS5Cu8 ) that dozens of the 760 monarchs released last fall likely survived the migration.
“It’s a big sign that the monarchs we are releasing are having a positive impact,” Walsh said.
The Toledo Zoo is one of many zoos, universities, and groups breeding butterflies in greenhouses and releasing them into the wild to prevent monarchs from disappearing, Walsh said.
He said the zoo tries to keep its greenhouses as sterile as possible and that every incoming egg is bleached. Walsh said only milkweed — which Monarchs feed exclusively on — grown in the greenhouse is given to the butterflies.
The zoo plans to release another 700 to 800 captive-bred monarchs between late August and late September.
Wild monarch butterfly populations have fallen an estimated 90 percent over the past 20 years.
Experts said last month the butterflies have made a big comeback in their Mexico wintering grounds after suffering serious declines.
The area covered by the orange-and-black insects in the mountains west of Mexico City this season was more than three and a half times greater than last winter.
The number of monarchs making the 3,400-mile migration from the United States and Canada steadily dropped in recent years before recovering in 2014. This winter was even better.
The zoo first released 250 butterflies in the fall of 2014, but none of them were found in Mexico months later.
“Just because butterflies aren’t recovered doesn’t mean they didn’t make it down there,” Walsh said.
Information from: The Blade, http://www.toledoblade.com/
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