To learn about what happens to our butterflies in the winter, we need to cover the life cycle of these beautiful creatures.
Butterflies pass through four stages- egg, larva (caterpillar), pupa (chrysalis), adult. This sequence can occur within one month or last up to ten months. A species can be identified at any of the stages.
Let's look at each of the stages:
First - the egg. They can be laid singly or in large groups. Often they are laid on the host plant twigs, so that the caterpillars immediately have a food source when they emerge from the egg. However, some species lay eggs on the ground or on other plants next to the host plant.
Second - the caterpillar. The eggs can hatch in five days. The caterpillar then passes through four or five stages, called instars. This can happen in fifteen days. The young caterpillar is an eating machine. At its youngest age, it eats more tender leaves or flower buds. As time progresses, it grows and molts its tight skin. Underneath, it has grown a new skin. One can identify the particular instars by its colors, and the sizes and densities of hairs.
Most caterpillars live alone, although, there are some that feed in groups. Few eat during the open in the day. They usually hide folded in leaves, under bark, or in leaf litter. If they do feed in the open, they probably have spines or taste awful to discourage predators. Tiny wasps or flies, however, consume most butterfly eggs and caterpillars. Out of one hundred, only two are needed to survive to continue the next generation of the species.
Third - the chrysalis. The chrysalis might be formed while the caterpillar is in the soil underneath the host plant or on tree trunks. Most caterpillars, however, develop a spinasilk pad, from which tiny hooks located on the posterior end of the chrysalis attach. Inside the chrysalis in that hanging position, the caterpillar parts are broken down and replaced by the adult butterfly parts.
Fourth - the adult. After it emerges from the chrysalis, it pumps fluid into its wings and then rests for about an hour before it flies. The males usually emerge before the females. This makes it easier for the latter to find a mate.
With this background, now we can talk about how butterflies survive cold temperatures.
Some butterflies migrate north during the spring and their offspring return to the south in the fall. The most well known one is the Monarch. About 100 million arrive in the Transvolcanic Range of mountains in central Mexico. Many have followed natural areas like coastlines, mountains and rivers. Like birds, they rest in Point Pelee in Ontario, Long Island beeches, Cape May, New Jersey, and Texas. Going back north in the spring is a different story. Few make it to the northern United States. They rest in the southern United States and northern Mexico and lay eggs on the milkweed. Their offspring finish the trip.
Some butterflies hibernate or over winter here. It is interesting that all the individuals of a species pass hibernation in the same stage- egg, larva, pupa or adult. Then, they do not enter a new stage until the hibernation is over. Those that hibernate in the adult stage have blood that does not freeze. Freezing would form ice crystals that would kill them.
The Cranberry-Bog Copper hibernates in the egg stage. They are laid underneath leaves and stems of their host plants-even under water. Then, the larvae eat the shoots and leaves of the plants. The adult visits cranberry flowers to sip raindrops.
The Great Spangled Fritillary first-stage larvae hibernate. The adults emerge from late June through July and early August. Look for them mating on flat-topped flowers like milkweed or Joe-Pye Weed. After that the female searches for a suitable site for her eggs- usually near violets which are usually dormant by this time.
The Cabbage White chrysalis hibernates. After it emerges, the adult can last from April to September or October. This is unfortunate for those of us who garden because if feeds on plants in the mustard family like cabbage, broccoli and nasturtium.
The Mourning Cloak adult hibernates. They might hide behind bark. The adult emerges in June or July. After mating, the male usually expires while the female lays her eggs to begin the new generation. The adults feed on tree sap from such as specimens as willows, poplars and sometimes elm trees. They also sip flower nectar and mud nutrients. This interesting butterfly may be one in our area that lives longer than most species as an adult- ten to eleven months.
There is much research yet to be done concerning butterflies. I hope that this introduction at least makes you aware of the diversity in this interesting creature.
Sanctuaries like the Jamestown Audubon are wonderful habitats to observe butterflies. We are located at 1600 Riverside Road, off of route 62 between Jamestown and Warren. On Saturdays and Mondays the center is open from 10 to 4:30. It is open from 1 to 4:30 on Sundays. The trails, which are great for walking and cross-country skiing, are open from dawn to dusk. Call 569-2345 or visit www.jamestownaudubon.org for more information.
Ann Beebe is a volunteer in charge of the gardens at the Audubon. Many thanks to Ted Taft for his expertise.