28 July 2008

Monarch chrysalis formation



The last time I featured the monarch caterpillars, they were forming "Js" on the top of their enclosures.

I was lucky this week to capture one of the Js in the process of splitting open to reveal the chrysalis inside (upper photo). The process of metamorphosis requires shedding of the antennae, legs, and head, along with the skin; all of that material is wriggled into a ball and accumulates at the top near the attachment to the roof (then it falls off). What is left behind is the chrysalis, inside which the butterfly will form.

In the upper photo of the splitting "J" I think you can discern in the background a second - earlier - chrysalis, under the surface of which the monarch wingpattern is already evident. The lower photo shows the undersurface of the lid of the enclosure, with the cohort of cats and chrysalids. Monarch butterflies should begin emerging about 10 days from now.

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