Gravestones! Ghosts! Goblins! exoSkeletons! You may have seen some of these at the Glencarlyn Library Community Garden this last day of October. Several black swallowtail caterpillars cling to the fennel. Will they grow large enough before the first frost to form chrysalises in which they can overwinter? As each races time and matures from one instar* to another, it sheds its exoskeleton, often devouring it for nourishment. Today’s demonstration seems to be in the Halloween spirit. Hope your treats are as satisfying.
Various instars of Eastern Black Swallowtail caterpillars
photographed at the Glencarlyn Library Community Garden, Arlington, Virginia.
*”Caterpillars go through 5 stages of growth. Each stage is called an “instar.”
As a caterpillar grows, it “molts” 5 times before it becomes a chrysalis. Each time it molts the caterpillar progresses to the next instar (1st instar, 2nd instar, 3rd instar, 4th instar and 5th instar).
Its skeleton is on the outside of its body, like clothes. So, as it grows, it can no longer fits in its skin.”
from Journey North
Here are additonal websites with more information on Black Swallowtails:
Thanks to the Extension Master Gardeners who contributed to this post: Mary Free (video and photos), Elaine Mills (photos), and Judy Funderburk (links).