Butterflies
In
a kaleidoscope of color, the butterfly lilts from plant to plant
with a quiet grace. Butterflies belong to a group of insects
called Lepidoptera. With approximately 500 scales per every inch
of wing, Lepidoptera, which means “scaly wings,” is appropriate.
Like all insects, butterflies have a hard outer covering called
an exoskeleton, three distinct body parts: a head, thorax and
abdomen, and three pairs of segmented legs.
There are over 550 different species of butterfly in North
America, and they come in a breath-taking array of colors.
Butterfly wings are clear, but pigment in and structure of wing
scales create colors. Pigment produces familiar colors like
brown, black, tan, orange, yellow and red. The way light
reflects off or moves through the structure of a scale creates
metallic and iridescent sheens, blues and greens. Both pigment
and scale structure work together to create white, purple and
ultraviolet color.
An adult butterfly can see a wider spectrum of color than
humans. Males and females of some species, like whites and
sulphurs, look identical to the human eye. A butterfly is able
to see the ultraviolet color on the males. Many flowers that
butterflies get nectar from have ultraviolet color, as well. To
most animals, the daisy appears as two colors - white petals
with a yellow center. Butterflies see a third color,
ultraviolet, outside the yellow center. Green vegetation absorbs
ultraviolet light, so ultraviolet-colored flowers boldly appear
to a butterfly.
A butterfly’s body temperature must be between 85 degrees and
100 degrees Fahrenheit to fly well. When the sky is cloudy or
the air temperature cool, butterflies can be seen basking. They
use their wings like solar panels to warm their bodies.
A few hundred years ago, the developmental stages of the
butterfly were not understood. Early naturalists thought
caterpillars and butterflies were completely different animals.
For centuries it was believed that caterpillars came from the
morning dew that formed on tree leaves.
Today biologists know that a butterfly progresses through four
life stages. It begins as a tiny egg attached to the leaf of a
host plant. The larva, or caterpillar, emerges and begins to eat
the leaves of the host plant. Because the skin of a caterpillar
does not stretch, it forms a second layer of skin and molts the
older, outer layer in order to grow. After molting four to six
times, the caterpillar has grown to its full size and is ready
to become a pupa, or chrysalis.
The final stages of development are called a metamorphosis,
which means, “change of form.” To prepare for the pupal stage,
the caterpillar spins a patch of silk from itself to a plant or
other object. The pupal skin begins to form beneath the
caterpillar skin. When complete, the caterpillar skin splits and
exposes the soft pupal skin, which gradually hardens into a
pupal case.
Growth cells that were not allowed to develop during the
caterpillar phase now form into structures and organs that are
found on the adult butterfly such as antennae, wings and
tongue-like mouthparts. After two weeks to four months,
depending on the time of year and species, the pupal skin
splits. The adult butterfly crawls out, its wings folded up and
moist. The butterfly hangs upside-down until its wings harden.
The transformation is complete, and it will spend the remainder
of its life in winged-form, proving the adage that beauty truly
does arrive with age.