US and Mexican scientists have learned that the biggest threat to the local population of monarch butterflies may be the powerful storms and hurricanes which are becoming more frequent in the region.
The researchers made their discovery while studying the butterfly colonies in the Monarch Butterfly Biosphere Reserve located on the border of both Michoacán and the State of Mexico, which contains most of the overwintering sites of the eastern population of the monarch butterfly.
According to a study the scientists published in the American Entomologist, a severe late spring storm that hit central Mexico in March 2016 stripped the butterflies of the thermal protection that was normally afforded by fir trees in the region, with up to 38 percent of butterflies in the Sierra Chincua and Cerro Pelón overwintering colonies being killed by lethal freezing.
"The unexpected effects of this storm may take place at greater frequency in an era of changing climate," the scientists warned.
