Hundreds of Caterpillars Released to Benefit Endangered Butterflies

Caterpillar and Butterfly

Story at-a-glance -

  • Taylor's checkerspot butterflies are in imminent danger of extinction
  • There are only an estimated 2,000 adults left in the wild, 75 percent of which are located in Oregon
  • Washington state biologists, together with the Oregon Zoo, raised more than 500 Taylor’s checkerspot caterpillars and released them into prairie areas earlier this year

By Dr. Becker

Butterflies are revered for their beauty, but it’s often forgotten just how important these majestic insects are to preserving healthy ecosystems around the world. Butterflies have existed for at least 50 million years,1 and while bees are often thought of as the primary pollinators in the US, butterflies play a major role in this area as well.

In fact, many native flowers can only be pollinated by butterflies, which have a long proboscis that can reach into a deep flower blossom.2 Also, bees tend to stay contained to a local area (unless beekeepers physically move them), but butterflies travel over large areas.

Monarch butterflies, for instance, can travel from 50 to 100 miles a day, cross-pollinating all along their way. Aside from their work as pollinators, butterflies have long been recognized as indicators of biodiversity.

If butterflies are thriving, there’s a good chance the ecosystem is healthy and teeming with other invertebrate life. Many other species, from predators to parasites, depend on butterflies for their survival as well.3 But, being relatively fragile creatures, if butterflies are struggling it’s often an early warning sign that something is amiss.

This is why the declines in butterflies being experienced around the world are more than unfortunate; they’re an environmental tragedy. It’s also why efforts to increase butterfly populations are so incredibly important…

Hundreds of Caterpillars Released to Support Endangered Butterflies

Taylor's checkerspot butterflies are in imminent danger of extinction, according to The Xerces Society for Invertebrate Conservation. They report:4

“There are only fourteen known populations in Washington and Oregon, with almost three-quarters of the known population at only two sites. Taylor’s checkerspot is threatened most by the degradation and destruction of its habitat.

Agricultural and urban development, encroachment of trees, and spread of invasive plants all continue to threaten the native grasslands in which it is found. In addition, pesticide use and recreational activities pose a direct threat to the butterflies themselves.”

There are only an estimated 2,000 adults left in the wild, 75 percent of which are located in Oregon. Unfortunately, Oregon State’s Threatened and Endangered Species List excludes invertebrates, so even though these butterflies are nearly extinct, they’re receiving no extra protections – at least at the government level.

Fortunately, Washington state biologists, together with the Oregon Zoo, raised more than 500 Taylor’s checkerspot caterpillars in the zoo’s butterfly conservation lab. Earlier this year, the caterpillars were released into prairie areas that represent prime checkerspot habitat.

The hope is that, when the butterflies emerge from their chrysalises, they will begin to re-populate this area, which was once home to checkerspots in abundance. Since 2004, the Oregon Zoo has helped raise 19,000 checkerspots for release into the wild. According to their website:5

They once fluttered across prairies west of the Cascade Mountains from British Columbia through Oregon's Willamette Valley. Today, 99 percent of their range has become farmland, pasture and city. The zoo is rearing and releasing checkerspot butterflies to build populations and restore this pollinator to the remaining areas of its historic range.”

Other Butterflies at Risk of Extinction …

Taylor’s checkerspot butterflies are only one species in danger of disappearing from the earth. An assessment completed by NatureServe and The Xerces Society for Invertebrate Conservation revealed, in fact, that North America’s iconic orange-and-black monarch butterflies are also vulnerable to extinction.6

Due to the increased use of herbicides like Roundup on genetically modified crops, milkweed is disappearing. The monarch butterfly cannot survive without the ample presence of milkweed.

This perennial plant is the only plant on which the monarch will lay its eggs. Once the larvae hatch, the caterpillar eats the plant. Without milkweed along its migratory path, the monarch simply cannot reproduce.

The loss of milkweed, combined with other threats like logging at overwintering sites, extreme weather, diseases, parasites, and insecticides used in agricultural areas, has resulted in monarch populations facing a dramatic decline.

Like monarchs, the larvae of the Oregon silverspot butterfly also rely on just one single host plant to survive – in this case the western blue violet. As its habitat has disappeared, so too has the population in droves.

The Oregon silverspot butterfly is now listed as a threatened species; conservation efforts are underway to introduce more western blue violet into its range while raising and releasing more butterflies into the wild.7

How to Attract Butterflies to Your Backyard

If you want to help support monarchs and other butterflies, plant milkweed where you can and a butterfly garden, too (milkweed is poisonous, so keep it out of reach of children and pets.) Additional plants that will attract and help support butterflies include the following:8

Coneflowers Impatiens Marigolds
Phlox Sunflowers Verbena
Asters Bee balm Butterfly weed
Chrysanthemums Daisies Purple coneflower
Sedum Yarrow New England aster
Bergamots Black-eyed Susan Butterfly flower
Coreopsis Purple ageratum

Finally, butterflies love to warm up in the sun, so a few flat rocks, placed strategically in sunny, protected areas, will provide a perfect spot for butterflies to catch some rays. They also enjoy “puddling,” which is when butterflies gather on wet sand or mud to absorb the minerals from the soil.

If you want to create a puddling area for butterflies, place a shallow pan in your garden, fill it with coarse sand and keep it moist.9 With the proper plants, access to sun and puddling spots, butterflies will be happy to call your backyard home.