Forest Feature: Butterflies
In July, our Pacific Northwest “Forest Feature” is the butterfly. Butterflies, like moths, are species of insects in the order Lepidoptra.
Nearly 200 species, representing seven families of butterfly, are found in the Pacific Northwest – Hesperiidae, Lycaenidae, Nymphalidae, Papilionidae, Pieridae, Riodinidae, and Satyridae.
Moths are also members of the Lepidoptra order, but, there are some differences between them and their butterfly cousins: Butterflies have thready antennae with a knobbed or hooked tip, while a moth’s antenna may be thready or feathered, but will tapers to a point at the end. Both moths and butterflies hatch as caterpillars, but moths will cover their cocoon in fiber, soil, or leaves; a butterfly transforms to its adult form inside a smooth-coated chrysalis. Butterflies fly during the day, while moths are usually active at night.
Three butterflies native to the Pacific Northwest are protected under the federal Endangered Species Act. The Oregon Silverspot (Speyeria zerene hippolyta) is federally listed as threatened, while the Taylor’s Checkerspot (Euphydryas editha taylori) and Fender’s Blue (Icaricia icarioides fenderi) butterfiles are listed as endangered species.
There are several reasons for this, but, a major one is that catepillars may be hungry, but some of them are picky eaters. Adult butterflies feed on pollen from many different sources. But as caterpillars, their eggs may need to be laid on on a specific species of plant to survive. This selectivity makes their species very vulnerable to invasive plants and noxious weeds, if those plants that crowd out the plants those caterpillars rely on, and to any environmental or other habitat changes that affect their preferred species for feeding or shelter.
You may think of butterflies as sun-loving creatures – and they are! Butterflies are cold-blooded, and must stay warm to fly. But forest meadows are a very important habitat to to Oregon Silverspot: The Siuslaw National Forest is one of the few remaining places you might spot it this butterfly; which thrives on foggy, breezy conditions.
Two of the six known remaining populations of Oregon Silverspot are on the forest, at Mt. Hebo and Cascade Head.
The butterfly’s survival is dependent on the early blue violet, Viola adunca, the only species on which the butterfly can successfully feed and develop as larvae.
Taylor’s Checkerspot butterfly has lost 99% of its native habitat to development and suppressed wildland fires; paved roads, new buildings, and even trees have overtaken the prairie meadows that once hosted the native plants the butterfly relies on to lay eggs and for its caterpillars to feed upon after hatching.
One of the last remaining breeding areas for Taylor’s Checkerspot butterfly is a military base, where explosives used in training set fires that have preserved the open prairie. Eggs are collected from Joint Base Lewis-McChord in Washington State each spring, raised under the supervision of scientists at the Oregon Zoo, and released back into the wild as caterpillars the following year.
The Fender’s Blue butterfly faces similar challenges in its native habitat, the upland prairies of the Willamette Valley. Establishing federally-designated protected habitat, using prescribed fire to expand prairies and reduce invasive grasses, and re-planting the prairie with native wildflowers – including Kincaid’s lupine, on which the butterflies lay most of their eggs – has helped increase the endangered butterfly’s numbers since it was federally listed in 2000.
The black-and-orange Monarch butterfly, Danaus plexippus, might be one of the most recognizable butterfly species in our region. This regally-named butterfly found throughout North America, including the Pacific Northwest. Its larvae grow on several species of milkweed.
Entymologists (researchers who study insects) warn that while the Monarch butterfly isn’t endangered yet, its numbers have been declining rapidly for a decade.
One theory is the butterflies are running into problems finding flowers, or flowers free of pesticides, when they migrate south for the winter. Another is that deforestation has reduced their winter habitat, and stressed the butterflies who crowding in to overwinter. But no one is quite sure.
Do you want to help butterflies survive and thrive here at home in the Pacific Northwest? One way to help is to plant species of flowering plants and shrubs that feed caterpillars for butterflies that are native to your area around homes or public spaces.
Have you heard of a “butterfly garden?” According to the Washington Dept. of Wildlife, you can plant a garden that feeds butterflies in a space as small as a container outside your home!
Butterflies like to feed on brightly-colored flowers planted in sunny places, especially those that are protected from the wind. You can find a list of suggested plants in this brochure. Not only will the flowers help butterflies (and moths), they may also attract other pollen and nectar-loving creatures – including hummingbirds, and bees!
Try to avoid using insecticides – even organic ones, like Bt (Bacillus thuringiensis) – when you can. If you do use them, follow the instructions and follow your state agriculture service’s recommendations to minimize the risk of exposure to beneficial worms, caterpillars, or insects in your area.
One plant that should not be part of your butterfly garden is the “butterfly bush” (Buddleia davidii). This bush is native to Chile, and is considered a noxious weed and a highly invasive plant in the Pacific Northwest – which means it could become a threat to native plants that our local butterflies depend on.
Did you know?
- Butterflies “taste” with their feet.
- Butterflies can “see” ultraviolet light.
- A butterfly’s skeleton is on the outside of its body. The exoskeleton protects it and keeps it from drying out.
- A butterflies tongue is like a long straw, which curls back up under their body when not in use.
- Some butterflies don’t poop! They burn everything they consume to generate the energy to fly.
- The largest butterfly in the world is Queen Alexandra’s birdwing, Ornithoptera alexandrae. It has an average wingspan of almost 10”! No one is sure what the fastest butterfly is
- Butterflies live in nearly every habitat, on every continent in the world – except Antarctica. This might be because butterflies are cold-blooded, and can’t fly if their body temperature drops below 86 degrees F.
Butterflies and Moths of North America (Butterfly and Moth Information Service):
Butterflies and Moths of Pacific Northwest Forests and Woodlands (USDA Forest Service):
Endangered & threatened species:
U.S. Fish and Wildlife Service: ESA listed species information
Oregon Zoo: Endangered and Threatened species conservation programs
Siuslaw National Forest: Oregon Silverspot butterfly info
North American Butterfly Association project (Butterflies and Moths of North America)
Butterflies and How to Attract Them (Washington Department of Fish & Wildlife):
Monarch butterfly lesson plans, activities, and projects:
Monarch Lab (University of Minnesota)
Forest Features highlight a new Pacific northwest species (or sometimes family, order or genus) each month as part of the USDA Forest Service Pacific Northwest Region’s regional youth engagement strategy. If you’re an educator who would like more information about incorporating Pacific Northwest environmental and forest science in your classroom, email us at R6Update@fs.fed.us.
USDA Forest Service, Pacific Northwest Region