Butterfly Metamorphosis by Joyce Graham Fogwill
Metamorphosis may be defined as a fundamental change in the structure and habits of an insect which accompanies
the transformation of a larva into an adult during their normal growth cycle. Some
insects like the butterfly or bumblebee undergo complete metamorphosis with different, distinct stages - egg, larva, pupa and adult, which look completely different
from each other. Other insects like grasshoppers
and termites undergo incomplete
metamorphosis or gradual
metamorphosis-the stages are egg,
early nymph, late nymph, adult. The nymphs resemble the adults
mostly in appearance, shares the same habitat and food, and have similar
behaviors. In winged insects, wings
develop as the nymph molts.
A few summers ago I watched and photographed the larva, pupa and emerged adult stages in process of Complete Metamorphosis in the Green Comma butterfly at Cape Broyle, Newfoundland. Please excuse the quality of the photographs
Egg:
Since I could not find eggs laid by butterflies in this garden, for information purposes I have included an image of the Monarch butterfly mating and egg stage. The eggs are very small and are laid on the leaves of the host plant by the adult female butterfly.
Monarch butterfly egg on underside of a leaf.
Monarch Butterflies mating
.
Photo by Joyce Graham Fogwill
from the Butterfly Garden – Museum
of Science and Industry (MOSI)Tampa, Florida.
The eggs hatch in 3-5 days into a.............
Larva or Caterpillar
This
stage lasts 5-10 days and the caterpillars have chewing mouth parts, tiny eyes,
stubby legs, short antennae and they eat and eat and eat. Each species will eat
only a single or single related plant species. The larva keeps eating, grows,
forms a new skin underneath and the old skin splits. This is called molting-
changing its skin to accommodate its growing size. After each molt the larva is
called a 1st, 2nd, 3rd and 4th instar.
The larva then finds a place to rest. In this example –the wall of the house.
A silk thread-spinneret is formed from a hole below its mouth and this is used to spin a pad to which the forming pupa attaches. After the final molt the skin splits open to reveal a dull straw colored, …………
Larva and Pupa (Chrysalis)
Danger - as a spider spins its web and waits to trap the emerging butterfly
The pupa is re-formed into a butterfly in 7-10 days. The pupal case splits open and the
adult butterfly struggles out.
My 7 year old neighbor M., a young nature lover and budding Naturalist, collected caterpillars, placed them in a jar, and after several days, this adult butterfly emerged from its pupal case. The body of pupa has now been transformed into the adult butterfly, having a segmented body with six legs, two antennae, wings and sucking mouth parts. The wings at first are soft and wet and the butterfly rests as it pumps fluids through its veins to its wings, which then expand and harden.
Imago-Adult
stage and empty pupal case on the side of the jar
empty pupal case
Newly emerged adult butterflies with
wings closed. Resting emerged adult butterfly with open wings
Some
species of butterflies live for about 10-14
days, while others live much longer. Some butterfly species hibernate during winter and may live
for several months, while others like Monarch butterfly migrate hundreds of
miles to warmer climates.
Joyce Graham Fogwill is a former Instructor in Biological Technology at Red River College of Arts, Science & Technology in Winnipeg, Manitoba, Canada.
Joyce is the author of the
Bubs the Bumblebee children's nature books by Joyce
Graham Fogwill.
Book 1: Bubs the Bumblebee and her most unfortunate, fortunate
adventure.
Website: http://www.BubstheBumblebee.com
