This article is by Layne Cameron, Nate Haan and Doug Landis and was published by MSU Today on March 12, 2019.
You might think that mowing fields wouldn’t benefit monarch butterfly populations. New research from Michigan State University, however, shows that disturbances like mowing – at key times – might help boost the iconic butterfly’s numbers.
The results are published in the current issue of Biological Conservation, and they show that strategic grassland management benefits monarchs in two ways. First, monarchs lay more eggs on young milkweed – new growth after mowing – the sole food source for the butterflies in their larval stage. Second, fewer predators visit immature milkweed; more come during its mature stages, such as when it flowers.
“Monarch butterflies scout young milkweed to lay their eggs,” said Nate Haan, MSU postdoctoral research associate in entomology and the study’s lead author. “And in terms of a food source, milkweed is more like spinach when it’s young and comparable to cardboard as it ages.”