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(To compliment "Sam" The Story of a Cecropia Moth) What can we learn from the ordeals of Sam's life? |
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| Here is "Little Sam" just after chewing out of his egg. His birthday is June 11th 2010. | "Little Sam" is now four days old. He is already eating his fill on dogwood leaves. |
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In his wanderings from leaf to leaf, Sam has come across another colored caterpillar. This one seems even more different than Sam. It is a cecropia moth larva in third instar just like Sam is but has a much darker, almost black, body. |
How might this dark color effect survival in the wild? Could it help in not being noticed by predators? To Sam, in his travels, this color difference is not of any great concern. |
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By the fourth of July, the black caterpillar had shed into a normally colored fourth instar skin. It seems that, although outward differences were apparent, seemingly different individuals are often pretty much the same inwardly. |
Look closely and compare the third instar picture above with the fourth instar pictures below. Can you see the differences? |
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| Finally, on the evening of July 13th, Sam has shed into his 4th instar skin. He spent all day waiting for the new skin to develop inside. Then, Sam worked the old skin towards the rear, broke free and crawled out. |
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Views and hues of a pale colored caterpillar. July 17th: Sam is now four days into his fourth instar time of life.
Sam showing off his beautiful blue irridescence.This is how he is seen from above in bright sunlight.
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Above is Sam as the morning sun strikes him from a low angle. You can see the irridescent blue on the back just beginning to reveal itself. Why do you think cecropia caterpillars have evolved to show lighter blue hues when seen from the top but often look green when viewed from the side or below? Hint: Think of a bird in flight looking for a nice fat caterpillar to eat. Maybe the the light blue is harder for the bird to see looking down in direct sunlight from above. Darker green hues are also less visible viewed from within the shaded canopy below.
Sam is yellowish in color as is this sibling above. How might this effect their chances of survival; of being found and eaten by birds?
Above: Sam is now 8 days into his fourth instar of life. The blue color becomes more pronounced as the days pass. Also, a gradually deepening green ground color is noticed. Below: As Sam continues to eat and grow, his skin is stretching, allowing more green from his insides to show through.
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| July 22nd, Sam is found on a bed of silk. He is not moving around or eating. This behavior is a sign of another event in Sam's life.What do you think is going to happen? | The next day early in the morning the long wait is over. Within minutes, Sam will be seen in a new skin as he breaks free and crawls out of the old one. Here, the action has started. Compare the upper two pictures. Look at the head and segments. What is going on? |
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Working free and crawling out of the old skin was hard work. Look how the old dead skin is still fastened to the silk bed. If Sam had not obeyed the inner prompting to spin this before ecdysis he probably would have lost his grip while shedding and fell to his death. Can you find the old skin exuvia and head capsule in the photos above? |
After all this effort, Sam needs a good, nutritous meal. His jaws have not finished hardening, but the caterpillar is hungry. Instinct tells him to turn around. Why should Sam turn around? He does not need to know why; he just needs to follow the command of his being. In doing so, Sam finds a bountiful source of protein: his own skin! Within the hour, the skin is greedily consumed. |
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Look at this picture of Sam one week after his fifth instar shed. Folds seen on the skin show Sam still has a lot of growing to do. Right now the skin is not filled up. It is like a balloon only partially filled with air. In a few more days the skin will be stretched tight. He is usually seen eating and is always on the lookout for fresh leaves. |
Remember, Sam must eat his fill to last him through until next year and the rest of his life Sam has pretty much lost his gold yellow color. He is now indistinguishable from the other caterpillars. Does this increase Sam's chances of survival in the wild? |
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On August 11th Sam is prompted to do something very different from what he has done before. The urge to feel, poke around and pull leaves together is ovwerwhelming. |
Silk strands can be seen as Sam obeys the signal within to spin his cocoon. As Sam progresses the task becomes ever more complex. After a hard day of work, a complex cocoon will have been spun. |
| A month later, Sept 19th, Sam is now a golden brown pupa. Sam and his friend will spend the long cold winter deep inside their protective cocoons they worked so hard to make. |
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