Elizabeth Murphy, age 12, of South Portland, Me., for her question:
What is the life expectancy of a butterfly?
When a beauteous butterfly emerges from a pupa, she has reached the fourth and final stage of her fantastic life cycle. Her one and only purpose is to mate and lay eggs for the next generation of her species. Usually this is completed in a week or so, after which she either dies or is eaten. However, a few species manage to survive the winter, and recent research suggests how they manage to escape their famished foes.
About 100,000 insects belong in the glamorous order of moths and butterflies. Each species starts life as an egg that becomes a hungry caterpillar that becomes a pupa and hatches into an adult winged insect. The basic life story is the same, though each species has a somewhat different story to tell.
The gorgeous adult butterflies attract a lot of attention. Most of them are soon caught and eaten by birds, bats, hornets and numerous other famished foes. Maybe this is why nature crowds this adult phase of life into just a few days or weeks. However, some species escape their enemies and live to welcome the following spring.
We know that certain butterflies live longer because their bodies contain unfriendly chemicals. Some discourage their hungry enemies with horrible smells and flavors. Others contain poisonous cyanides, acids or alkaloids.
For example, the handsome orange brown monarch butterflies migrate to warmer winter climates and return in the spring. When a sassy blue jay decides to eat one of them, he has a violent attack of upchucking and learns never to touch another. It so happens that two monarchs contain enough poison to stop the heart of a starling.
We need a lot more research on the life spans of the numerous different butterflies. Possibly the average winged adult must crowd her final stage into a couple of weeks because she tastes so good to her famished foes. Other species may be able to live longer because they contain repulsive or even deadly substances.
In any case, most of the adult butterflies around South Portland, Me., have life expectancies of a few days or a couple of weeks. By now they have departed from the scene, or so it seems. Actually the handsome morning cloak is hibernating in some woodsy crevice. She will survive until spring, and on a sunny winter day you may spy her large, dark wings as she flutters forth for an airing.