Monarch Butterflies Reared in Captivity Lack a Crucial Ability
Wild monarchs have faced a steep decline in recent decades, Ed Yong wrote in June. Some North American companies and hobbyists breed stocks of the insect, many with good intentions of bolstering the monarchs’ numbers. But according to a new study, monarchs raised in captivity tend to have poor migration skills, and so releasing them might do very little to save the imperiled monarch migration.
“As a species, it’s likely that the monarch will survive for a long time,” the leader of the study told Yong. “But this phenomenon that we all know and love—the migration—seems to be very fragile.”
As a gardener, I’ve planted milkweed for years to support the monarch migration through my neighborhood. In the past, I’ve been happy to watch the adults from a distance, but after reading of their declining number, I decided to do a little more to increase their chances of success. This is the first year I’ve invested in enclosures to help the caterpillars develop safe from the opportunistic parasites and bacterial infections that have been killing many of them before they can become butterflies.
I agree that the benefits of these local, backyard efforts outweigh the risks of interfering with the monarch’s migration and navigational abilities—especially when done in the warm summer months to ensure that the caterpillars are happily eating and going through their life cycle outdoors in natural settings.
There are currently a dozen or more caterpillars in various stages of development in two different enclosures on my patio. There are plants in the front and back yards to attract the adults, and I collect the eggs and small caterpillars on a daily basis.
It’s a fascinating process. I hope more people will do this in their backyards.
San Diego, Calif.
Monarch-butterfly populations have declined by approximately 90 percent since the 1990s. Scientists agree that habitat loss, the use of pesticides, and climate change drive this decline. Annually, 1 million acres of new urban-suburban developments fragment wildlife-habitat corridors. Specifically, the eastern monarch’s central migratory flyway has lost more than 90 percent of the grassland ecosystems to agricultural land conversion.
We applaud the millions who are part of the movement to restore monarch habitat across North America. Most understand that the best way people can make a difference is to plant native milkweed, the only plant on which monarch caterpillars survive, and add native nectar plants to fuel their journey. To create a clean habitat, Americans should also reduce or eliminate the use of pesticides and herbicides.
While some feel strongly that raising monarchs in captivity is the best way to safeguard the species, there is no evidence that this approach will work at the scale needed to support migration.
The National Wildlife Federation understands that passionate home rearers are just trying to help. With Garden for Wildlife, we invite all to address the root issues of decline in healthy habitats for monarchs where you live, work, play, learn, and worship.
Senior Director, National Wildlife Federation’s Garden for Wildlife Program
Co-founder, National Pollinator Garden Network