A superstar, an instar, a super suffocated interinstar,
August 30, 2011 8:53 PM Subscribe
Why caterpillars molt.
posted by Cold Lurkey (21 comments total)
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The lifecycle of the lepidopteran, from egg to caterpillar to winged butterfly or moth has long been a basic lesson plan of "hands on" biology
in grade school classes.
If one focuses on a single lifestage of this grand cycle, however, one sees that the caterpillar, after emerging from embryogenesis quite small
, goes through several stages
, or instars, becoming more grand
at each shedding of the skin, until at last the massive
beast pupates. So what triggers these transitions within the caterpillar? Recent research suggests a process triggered by suffocation by bulk
In short, the low oxygen, induced by constriction of the passive flow through the respiratory trachea of the caterpillar drives each successive molt up to pupation. The constriction is caused, of course, by the hungry hungry caterpillar eating anything in sight.