Open your eyes to butterflies

From San Francisco to New York City, from the Canadian border to the southern tip of Argentina, Art Shapiro has traveled all across the Americas to study butterflies. But the winged wonders he knows best live right in his hometown of Davis in northern California. He's been chasing the insects since he was a kid.

"I got interested in butterflies around the fourth or fifth grade," Mr. Shapiro says. Growing up in Philadelphia, young Shapiro found butterflies were a way to get out of the house. "I had a dinky kid's net and a lot less savvy," he adds.

On a hot day last summer, Shapiro is armed with an adult-size butterfly net and decades of knowledge. We are in Davis, standing at a residential street corner. The owner of the house has planted a flower garden in the front yard. Not only can Shapiro spot butterflies I can't even see, but he can also - with a glance - usually identify the species.

"That's a gray hairstreak butterfly," he says, swiping his net. There are two techniques for catching butterflies. One is to pounce the net over the top of the insect. The other is a sideways swipe, followed by a flip of the net to keep the insect trapped in the mesh. Shapiro uses the swipe/flip method.

Carefully peeling back layers of net, Shapiro reveals a small, gray butterfly with tiny splashes of orange and black on its wings. On the the back edge of both wings, a hairlike piece extends. Shapiro explains that the "hairs" look like antennae and are a trick to fool anything trying to eat the insect.

Butterflies are fast, and any bird that wants to eat one has to move quickly. Birds usually try to bite the head of a butterfly. If a bird spots the hairstreak feeding on a flower, it may mistake the hairs for antennae. When the bird attacks, it ends up with a beakful of wings. The butterfly flits away, a little ragged but still alive.

"You can actually see that butterfly over there that is missing part of its wings," Shapiro says. Sure enough, there's a gray hairstreak missing the back part of its wings.

Butterflies come in more colors than the biggest box of Crayola Crayons. But the colors are not just to look pretty. They are important to the butterfly in many ways.

"I'm pretty sure we haven't figured out all the functions of butterfly colors," Shapiro says.

Colors help butterflies identify another butterfly of the same species, and whether it is male or female. The next time you walk through a grassy field, notice how two butterflies will flutter around each other, twisting and turning in the air. It looks like a dance. What is actually happening is that the butterflies are getting to know each other. If the butterflies are different species, with very different coloration, the "dance" ends quickly. But if the butterflies look similar, the dance lasts longer.

Color also helps butterflies get warm - or stay cool.

Humans are warmblooded, meaning that our bodies make heat. But animals such as lizards and butterflies get their heat from the sun. And this is how color becomes important. Dark colors absorb the sun's heat - think of a black T-shirt. Light colors, such as white, reflect the sun's energy and remain cool.

A common butterfly called the cabbage white uses color to warm its wing muscles. The cabbage white is originally from Europe but is now found all across North America. You've probably seen it in your backyard. It's medium in size with bright white wings. What you may not notice is that its tiny body is black.

Before the cabbage butterfly can fly away in the morning, it must get its wing muscles warm so they can function. It does this by aiming its wings to reflect the sun's rays. The white wings act like mirrors, concentrating sunlight onto the butterfly's body. Because it's black, it absorbs heat. This warms its wing muscles enough to allow the insect to fly away.

"Color also serves as a warning to animals that want to eat butterflies," Shapiro says.

Before becoming a butterfly, the monarch caterpillar feeds on the milkweed plant. Milkweed contains a foul-tasting toxin that the caterpillar stores in its body. The toxin remains in the body of the monarch butterfly. Many insects have muted or camouflage colors so that it's harder for birds to see them. The monarch butterfly does the opposite. It warns birds with bright orange colors to stay away. Any bird foolish enough to eat a monarch will get an upset stomach.

At the end of the day, Art found more than 20 kinds of butterflies. "Not too bad for one day," he says. Best of all, he found them all in his hometown. With practice, you could probably find just as many butterflies in your hometown as well.

When is a butterfly not a butterfly? When it's an egg, caterpillar, or pupa (PYOO-puh).

Butterflies are only butterflies for a few days to weeks. For most of their lives, they are caterpillars. The process starts when a female butterfly finds the perfect plant on which to lay eggs. Butterflies are very picky about their plants. Monarchs, for instance, lay eggs only on milkweed.

After spotting a plant, butterflies go in for a closer inspection. A butterfly's feet have special sensors that smell and taste a leaf. In the case of a monarch, the sensors make sure the plant is a milkweed and not, say, a rosebush. It's like having your tongue and nose on your sneakers.

If the plant is right, the butterfly lays eggs that hatch into caterpillars. Caterpillars do little more than eat and grow, eat and grow.

But the skin of a caterpillar does not grow. That means that, every once in a while, a caterpillar must shed its outer layer of skin so it can grow some more. The skin splits, and the caterpillar wriggles out the way you wriggle out of a sleeping bag: It "unzips" its old skin and emerges with a new one. Fresh and clean, it's ready to resume eating.

When the caterpillar reaches a certain size, two or three months after it hatched, it's time for it to become a butterfly. The caterpillar stops eating and usually spins a silk web around itself, making a cocoon. This cocoon will harden, forming what is called a chrysalis (CRISS-uh-liss).

Inside the chrysalis, the caterpillar changes dramatically: A mouth for chewing plants disappears, and a mouth for sipping flower nectar appears. Short stubby legs disappear; long, thin legs appear. Wings start to grow.

After some time, the chrysalis splits open. Out crawls a butterfly. It flaps its wings and takes off to begin the cycle anew.

Greg Kareofalas is a retired engineer living in a typical suburban home in Davis, Calif. At least, that's how it appears. But in his backyard, things are a little different. Mr. Kareofalas, you see, loves wild animals. But because he lives in a small city, he can't expect to see bears or deer out his windows.

So instead Kareofalas has made his backyard a perfect habitat for smaller wild things: butterflies. As he explains, two kinds of plants appeal to butterflies. Flowers are obvious because they attract butterflies that sip the nectar. Nectar is a butterfly's only food, so Kareofalas plants tons of flowers and flowering bushes, including "butterfly bush." But that's only part of it.

"You really want to make it attractive for caterpillars," he says. "A butterfly is only a butterfly for days or weeks, but a caterpillar is a butterfly for months."

To bring in butterfly caterpillars, Kareofalas plants "weeds" for them. Butterflies are picky about which plants they lay their eggs on, but six kinds of plants are especially butterfly-friendly. They grow everywhere in the continental United States. You could probably grow them, too.

Here are Kareofala's tips to attract butterfly caterpillars to your yard.

Now is the time to start thinking about where to put your butterfly plants. You need a place that won't be sprayed with pesticides. It should be easy to water, too. You don't want the plants to dry out.

These are the plants that attract the most common butterfly species in the US:

Alfalfa: It's a grass that will grow in just about any sunny location. You can find seeds at a plant store or health-food store. Alfalfa attracts such butterflies as the orange sulphur. Look for caterpillars that are green and wormlike.

Parsley: The same herb that garnishes your plate is the favorite food for caterpillars that become anise swallowtails. The caterpillar will be smooth skinned with a yellow-and-green checkerboard pattern. (It's very attractive, as caterpillars go.)

Baby tears: This plant grows wild in many yards. It attracts red admiral butterflies. Its caterpillars are spiny (which discourages predators).

Hollyhock: This old-timey plant might be in your grandmother's garden. It's tall, with beautiful, trumpetlike flowers. Best of all, it grows in just about any sunny location. Look for the spiny caterpillars of painted lady butterflies.

Millkweed: You can often buy milkweed from local garden groups selling native plants. Milkweed is not very pretty, but it attracts beautiful monarch butterflies. The caterpillars are a showy black, yellow, and white.

Broccoli: It may taste yucky to you, but it may be crawling with little green caterpillars that find it delicious! They will turn into cabbage white butterflies, an import from Europe that is common across the US in the warmer months.