In this photo taken Feb. 15, 2013, Monarch butterflies are collected in a net to be tested for the ophroyocystis elektroscirrha parasite that inhibits
In this photo taken Feb. 15, 2013, Monarch butterflies are collected in a net to be tested for the ophroyocystis elektroscirrha parasite that inhibits their flight, at El Capulin reserve, near Zitacuaro, Mexico. Every year, millions of monarchs migrate from the eastern United States and Canada to central Mexico, a journey of over 2,000 miles. (Associated Press)