Wednesday, September 2, 2015

A Sticky Situation

Have you ever wondered how a Monarch Butterfly pupa clings to a leaf or other object while making the transition to an adult?  The gyrations of the pupa during the transition not only fails to dislodge the pupa but is actually necessary to insure a solid attachment that will anchor the  chrysalis through the next 14 days.

Super Glue? Elmers? Epoxy? Gorilla Glue?
No, but before there was Velcro there was nature!


The cremaster is the small black post that extends from the upper end of the chrysalis and the tip of this post is a round sphere covered with small barbs.  As the outer skin of the monarch caterpillar is forced to the upper end of the pupa the cremaster comes from under that skin and attaches to the web button that the caterpillar placed as a hanging location for its "J" position.  During this process the pupa seems to hang in mid-air,
 for seconds, during attachment of the cremaster. The aim of the pupa is perfect as the button is only slightly larger than the cremaster

The twisting and swinging of the pupa lodges the  hooks of the cremaster solidly in the fibers of the web as the skin drops free and the pupa's movement slows and gives it a much needed rest.
Photos by J. Ormiston 9/2/2015