Earth Notes
11:19 am
Wed August 22, 2012

Earth Notes: Milkweeds for Monarchs

If you’re out searching for one of North America’s most famed butterflies, the beautiful orange and black monarch butterfly, try looking in a patch of milkweed.

Monarchs sip nectar from milkweed flowers, and females lay their eggs on the plants. When those eggs hatch, the caterpillars feed exclusively on milkweeds. The milky white sap in the plants makes the caterpillars and butterflies taste horrible to any bird that tries to snack on them.

Over the last decade, though, monarch numbers have declined substantially in California, where most of the western population overwinters. That’s in part because host milkweeds are being lost to agriculture and development, mowing, and herbicide use.

The Xerces Society, an invertebrate conservation group, is turning to farmers for help. With support from the Monarch Joint Venture and the Natural Resources Conservation Service, it has launched “Milkweeds for Monarchs,” a program to increase the availability of milkweed seed in the southern part of the monarch’s breeding range. The group is working with growers in Arizona and New Mexico to produce seed of native plants and make it available for habitat restoration projects.

In Skull Valley, Arizona, the Painted Lady Vineyard transplanted two thousand seedlings of spider milkweed this summer. They hope to harvest several pounds of seed next spring, mostly by hand but possibly with machines too.  Even in tiny plots at home or near schools, a few milkweeds can help support the West’s embattled monarchs of the garden.