August 23, 2010

Monarch Caterpillar Season

It's monarch caterpillar season at High Point! Monarch butterflies have been busy laying their tiny eggs on the underside of milkweed leaves. 
(That's a dime next to the egg.)

The tiny caterpillar hatches and eats and grows, and eats and grows, and eats and grows, until it goes through five instars. At the end of each instar the caterpillar stops eating for a period of time and sheds its skin.

When the caterpillar has completed five instars it starts to take on a bit of a greenish cast, and leaves the milkweed in search of a safe place to transform into a chrysalis. It weaves a web and hangs from it in the shape of the letter "J."

When it is ready, the caterpillar begins to wiggle and contract, splitting its skin. Watch the video - it's hard to describe! At the end you'll see the chrysalis swing around like crazy. This is a delicate stage. It is twisting its cremaster, the little black stem-like appendage at the top of the chrysalis, into the silken web. If it doesn't do this successfully, the chrysalis will fall to the ground and will not complete its transformation into a butterfly.
(Be patient, the first 10 seconds of the video are blank.)


Once it is free and securely attached, the chrysalis continues to change shape over the next half hour to an hour, until it finally hardens into the beautiful jade-green chrysalis that most of us recognize.

Stay tuned for butterflies!
To learn more about monarchs and their host plant, milkweed, come to the Interpretive Center on Friday August 27th at 11:00 AM. (For more program details click the August tab at the top of the page.) You can also visit Monarch Watch which is an impressive clearinghouse of Monarch information.