Tag: moths

A Bear You Can Hold in Your Hand

The Isabella Tiger Moth Caterpillar – AKA Woolly Bear

Covered in fuzzy bristles, some are more black or more orange, but all have both colors. The one I found today was a beautifully dressed banded woolly bear, with black at each end and orange in the middle. Better known than its adult form – the Isabella tiger moth, the woolly bear elicits more pleasant reactions from people of all ages than most other caterpillars. They are cute and harmless, and don’t seem to mind being picked up.

There are similar caterpillars that are solid black or brown or other colors, and they can be called woolly bears, but they are different species. Only the larva of Pyrrharctia Isabella, the Isabella tiger moth, is the familiar black and orange banded woolly bear. Their bodies have 13 segments covered in stiff hairs.

First named in 1797, it’s not clear who this moth was named for. I know there was Queen Isabella of Spain. But these moths are found only in North and Central America.

The folklore of the woolly bear is said to stretch back to the American colonial days. The lore suggests that the width of the color bands relate to the upcoming winter. The thought is, if the orange band is shorter than the black, its means a snowy winter.

How could this be? People have tried to prove this notion, to no solid evidence. Researchers have crunched the weather data over periods of time and compared it to the markings of the caterpillars, finding no scientific evidence to support the folk tales.

We typically see the caterpillars in fall simply because that’s when the eggs hatch, though some do hatch in summer. They spend the summer munching on a wide variety of plants, getting ready for winter hibernation. When fall comes, they find a sheltered place, under a stone or log, or even underground. They have a kind of antifreeze that helps them survive very cold temperatures.

Cocoon (not my photo)

As soon as it warms up the next year, they emerge and begin to feed. Soon after, they make their cocoon, and within two weeks, the adult moth emerges, to begin the cycle again.

Like other moths, the Isabella tiger moths don’t live very long. They live simply to mate and lay eggs.

Isabella tiger moth (not my photo)

The moths don’t eat. I have never seen one, but they are attractive, with yellow-orange body and wings, and little black spots. The wingspan is about two inches wide.

If you see one, you’ll know winter is coming. The question is, what kind of winter?

A Caterpillar Feast

In March, I journeyed back to the Anza-Borrego Desert in southern California. The big draw was an annual migration of Swainson’s hawks and the emergence of big colorful caterpillars, but as it happened, a third phenomenon blossomed simultaneously.

Big colorful caterpillars emerge every spring in Anza-Borrego.

They are the larvae of the white-lined sphinx moth and appear in various color combinations, from yellow with black stripes, to black with yellow stripes, to green with black stripes.

The caterpillars, sometimes called hornworms, feed on many types of flowers and plants, while the moths seek nectar.

The striking moths, also known as hummingbird moths, can be quite beautiful.

What I witnessed was the part of the life cycle when the larvae hatch and proceed to munch out on the desert flowers and plants.

It just so happened that this year the little guys were even luckier to hatch during a “superbloom,” a time when bountiful winter rains have produced carpets of wildflowers across the desert.

After eating nonstop and growing to 3-4 inches in length, the time comes for the next phase of their lives. The caterpillars burrow into the sand and pupate into a form that remains underground for 8-15 days. Then, the big transformation occurs and the moths emerge!

The moths spend their nights feeding and pollinating wildflowers, and then lay eggs on the undersides of flowers. The entire life cycle begins anew when the eggs hatch into very small caterpillars that begin to eat 24 hours a day on the flowers.

At the same time, Swainson’s hawks are making their way north from South America. They spend time in the desert around Borrego and have been known to feast on the caterpillars. Birders gather daily for the hawk watch. It was a gamble where or when they might be spotted. During my visit, I was disappointed to see that the hawks were in kettles a great distance away. Meer specks. I had expected to see them near the ground picking off the fat worms.

Unfortunately, I could not stick around long enough for the emergence of the moths, but I bet that’s something to see!

The superbloom, however, was a great treat.