The Butterfly Effect

by | Aug 1, 2008 | Conservation

ON WARM, SUNNY DAYS when Patty Eason enters her Georgetown, Texas, garden, her mood always brightens. What puts that extra spring in her step? Butterflies.

The multi-colored winged visitors flitting about Eason’s all-native garden give her something to smile about. “Butterflies add movement and serenity to the garden and give you a light, happy feeling that there are good things going on around you,” says Eason, whose garden has been featured on the program “Central Texas Gardener,” which airs on the PBS affiliate KLRU. “People are intrigued by the certification of our landscape for being completely native and a diversity habitat and will wander down the driveway to look. They become more enthusiastic when they observe the abundance of butterflies and birds.”

Eason lives in the center of an old established urban neighborhood with her husband, Rick, and attributes the abundance of butterflies in her garden to her native landscape. It includes more than 33 species of natives that attract butterflies, including yellow passionflower (Passiflora lutea), yellow canna (Canna glauca), bushy bluestem grass (Andropogon glomeratus), Texas aster (Symphyotrichum drummondii var. texanum), coral honeysuckle (Lonicera sempervirens), soapberry (Sapindus saponaria var. drummondii), snapdragon vine (Maurandella antirrhiniflora), chile pequin (Capsicum annuum var. glabriusculum) and Texas lantana (Lantana urticoides).

The myriad butterflies inhabiting Eason’s backyard, such as Gulf fritillaries, blues and buckeyes, might give the impression that hers is a long-established garden, but the truth is she planted her landscape just a few years ago, in February 2003, and started seeing butterflies almost immediately. “Butterflies love my native plants, and they just keep coming,” she says. “Neighbors will tell me they have no butterflies, and I’ll tell them to come over and see the show.”

While gardens with non-natives do attract some butterflies, landscapes that feature native vegetation play the perfect host to these graceful beauties.

“In general, it’s better to use natives to attract butterflies because they’ve co-evolved and are well suited for one another,” says butterfly ecologist Ernest H. Williams, who is a professor of biology at Hamilton College, in Clinton, New York, author of “The Nature Handbook” (Oxford Press, 2005) and co-author of the “Stokes Butterfly Book” (Little Brown, 1991).

“Non-natives like [some] buddlejas do attract butterflies to the garden, but they are often one-dimensional,” adds Steve Castorani, owner and co-founder of North Creek Nurseries Inc., which specializes in Eastern regional native plants, as well as American Beauties, a regionalized line of native plants offered at independent garden centers. “Non-native buddlejas [like B. davidii] offer only nectar, whereas a native like milkweed (Asclepias spp.) provides nectar and a food source for insects.”

Watch a butterfly float in a seemingly aimless pattern through the garden and you might be tempted to think of it as simply a decoration, but the truth is this insect has a number of important environmental roles. Surprisingly, butterflies are important pollinators. In North America, there are more than 700 species of butterflies, while worldwide there are about 28,000 species.

“Butterflies play an important role by pollinating many species of flowering plants,” says Wildflower Center director of horticulture Andrea DeLong-Amaya. “Without this pollination, of which nectar is typically the reward, fertilization wouldn’t occur and seeds would not form to perpetuate the population.”

“While they generally aren’t as efficient as bees when it comes to pollination, in many cases butterflies are the predominant insect flying around flowers, and at specific times of the year and in certain situations they might even approach the effectiveness of bees,” says entomologist Mike Quinn, an invertebrate biologist with the Wildlife Diversity Program for Texas Parks & Wildlife. Some species of plants depend heavily on butterflies for pollination.

In their adult and larval stage, butterflies also are an important source of food for other animals, says Quinn. “Not all animals can digest plant materials, but most predators can digest caterpillars, which are an integral part of the food web. Songbirds, for instance, feed caterpillars to their nestlings.”

Besides their critical ecological contributions, butterflies provide a gateway to interest in other insects and raise awareness for insects in general, notes Quinn. “I had an epiphany regarding insects in my late 20s when on a hike during a bird project. I walked around a bend and ran into a giant swallowtail basking in the sun,” he says. “That experience ignited an intense interest in the insect world.”

Butterflies also can garner excitement among people – especially children – about gardening, says Castorani, who often has customers come into his retail nursery, Gateway Garden Center in Hockessin, Delaware, asking for plants that attract butterflies. This interest among gardeners in lepidoptera partially fueled his desire to start the American Beauties line of natives, which donates a portion of its proceeds to The National Wildlife Federation’s Backyard Habitat program. “We have four garden collections, and one of them contains plants that attract butterflies,” he says.

Gardens that lure butterflies have a variety of common features. “In order to design your butterfly garden, it’s important to understand the stages of butterfly growth,” says botanist and landscape designer Judy Walther, who designed the Wildflower Center’s Ann and O.J. Weber Butterfly Garden and is president of Environmental Survey Consulting in Austin, Texas, which does habitat restoration. (Her company designed the Easons’ native plant garden as well.)

“Creating a place for the butterfly to lay eggs and for the chrysalis to be safe from predators and weather is important, as well as providing food for the larval and adult stages of the butterfly growth,” says Walther. At the Center’s butterfly garden, which is home to 80 plant families and more than 300 species of plants to accommodate 90 of Central Texas’ most common butterflies, there are a variety of thickets that butterflies use to bask on and hide within as a refuge from predators, sun, wind and rain.

Basking (sunning) is important to a butterfly’s ability to fly, as for most species body temperature must be above 70 degrees to take flight, and its muscles must be warm, says butterfly ecologist Williams. (On a cloudy day, butterflies can shiver to warm up their flight muscles.) “The interesting thing to note is that with basking a butterfly’s body can heat up 10 to 20 degrees F higher than the ambient temperature,” he says.

“In the Northeast, for instance, the first butterfly of the season to appear is the morning cloak, which you’ll usually see flying around on a warm day in March when the temperatures are in the 50s.”

Most butterfly activity occurs when it’s sunny outside, although you’ll also see some flying around when it’s cloudy and warm, says Williams. There is very little activity when it’s cloudy and cool. If it is very hot, you will find butterflies seeking refuge inside vegetation and positioning their bodies to intercept as little sunlight as possible, as they must protect themselves from drying out and overheating.

Successful butterfly gardens contain both larval food and nectar plants. “Host plants attract butterflies to lay eggs, and the resulting caterpillars then feed and live on them, and nectar plants lure adults for feeding,” says John C. Abbott, curator of entomology at the Texas Natural Science Center at the University of Texas at Austin. In general, the more plant diversity in the garden, the more diversity in butterflies one can expect and the longer the butterfly season you will enjoy.

Some good nectar plants that keep butterflies coming include plants in the sunflower family, mallows like Turk’s cap (Malvaviscus arboreus), columbine (Aquilegia spp.), Mexican plum (Prunus mexicana), rock rose (Pavonia lasiopetala), mealy blue sage (Salvia farinacea), coreopsis (Coreopsis spp.), Indian blanket (Gaillardia spp.), black-eyed Susan (Rudbeckia spp.), button bush (Cephalanthus occidentalis), lantana (Lantana spp.), purple coneflower (Echinacea purpurea), gayfeather (Liatris spp.), mistflowers (Ageratina spp. and Conoclinium spp.) and yarrow (Achillea millefolium).

Others are milkweed (Asclepias spp.), buckwheat (Eriogonum spp.), deerweed (Lotus scoparius), coyote mint (Monardella villosa), goldenrod (Solidago spp.), California lilac (Ceanothus spp.), coffeeberry (Frangula californica), gooseberry (Ribes spp.), willow (Salix spp.) and cassia (Senna spp.).

Although nectar is a common goal of most butterflies, there are some species such as anglewings that don’t feed on the nectar of flowers but usually get their nutrients from plant juices, such as sap from a broken twig or split fruit.

Host plants where butterflies can feed and lay their eggs also are crucial to a successful backyard butterfly garden. Having a diverse collection of such plants is also important because certain plants are hosts to certain types of butterflies. Most notable is the monarch, whose caterpillars feed on milkweeds. Other larval plant-butterfly pairings include but are not limited to passion vine (Passiflora spp.): Gulf fritillary; flame acanthus (Anisacanthus quadrifidus var. wrightii): Janais Patch; oak (Quercus spp.): hairstreaks; nettles (Urtica spp.): red admiral; senna and partridge pea: cloudless sulphur; sunflower (Helianthus spp.): bordered patch; and California buckwheat (Eriogonum fasciculatum): Acmon blue. Some host plants also are good nectar plants, which makes them doubly useful.

Water is another important ingredient of the butterfly garden, but in deep water butterflies can’t swim and with wet wings they can’t fly. Instead, butterflies need puddles of wet sand, mud and/or animal manure from which they extract water, salts, amino acids and other nutrients. Known as puddling, this behavior is common with male butterflies because it allows them to develop the sperm packet for mating.

In the Wildflower Center’s butterfly garden, a puddling place resembling a natural limestone seep has drip irrigation providing enough water for shallow puddles on the rocks and a moistening of surrounding soil. In the home garden, Walther suggests creating a puddling spot with drip irrigation or with a rock that has depressions and holes that you can rinse and refill every few days. Place all puddling areas in a warm, sunny location.

A small number of butterflies are known for migrating. While the monarch is the most well-known traveler and makes a roundtrip migration (some populations travel from the Rocky Mountains to parts of Mexico, for instance), some other butterflies will do a partial migration or movement, as Williams refers to it. This is true of the cloudless sulphur, which moves up the Atlantic coast, and the painted lady, which travels along California’s coastline and throughout much of western North America. Laura Camp is with the Tree of Life Nursery in San Juan Capistrano, California, and she recalls one season in particular when thousands of painted ladies passed through. “It was surreal,” she says. “The butterflies came in droves and it felt like a plague, but a really nice one.”

When attempting to attract a butterfly species that travels, you must have the plant material it needs for the stage they will be in at the time they are migrating through your area, according to Samantha Elkinton, a gardener at the Wildflower Center. “If the butterflies are simply passing through, you will need a nectar source and plants en masse to attract them. When they are laying eggs, you will need the correct plant species for the larval food source.”

Many butterflies like the monarch will move through their migration pathways in the fall and spring, adds Abbott. In the fall, they will search for nectar sources, and in the spring they also will look for plants on which to lay eggs. A good butterfly garden changes with the seasons and with the community of butterflies that are expected throughout the year.

Written by Julie Bawden Davis