Monday 25 February 2013

Butterfly Metamorphosis by Joyce Graham Fogwill

 
 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 GardenMuseum 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

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