Giant Swallowtail (Papilio cresphontes) - Life Cycle 2014
Stan Malcolm Photos, Marlborough, Connecticut

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According to Jane O'Donnell, Lawrence F. Gall, and David L. Wagner in "The Connecticut Butterfly Atlas", Giant Swallowtails are only occasional visitors and breeders in Connecticut.  Most records are old.  Traditionally, we have been at the limits of the species' northern range.  However, with climate change, sightings of adults and caterpillars are on the increase.  I saw my first adult pass through my yard in 2012.  (I could hardly believe my eyes.)  The same year, I heard reports of caterpillars on Common Rue (Ruta graveolens) in Haddam (E. Falbowski) and Storrs (W. Henry).  In 2013, it was time to plant some Rue!  That year, I heard reports of caterpillars in Haddam again, and in 2014 in Haddam and Keene, New Hampshire (S. Jaffe). The Haddam reports were in August and September. I suspect they, and my caterpillar, may be the progeny of a late migration from further south.  So late in the year (October 8th), I'm not sure mine would have survived had I not transferred it to an indoor cage.  What happens next is anyone's guess: will it overwinter as a chrysalis or emerge shortly as an adult?  Or, worst case, will it harbor a parasitoid wasp. If it doesn't emerge in a couple of weeks, I'll store it in a cool place until spring.



October 8th.  Observed on Common Rue; Marlborough, Connecticut.












Many swallowtail caterrpillars are bird poop mimics in their early instars, but the Giant Swallowtail keeps it up through the entire series of larval stages.  That means a "mature" bird poop roughly 5 centimeters long.  When this photo was taken, it was a bit over 3 centimeters long.  (Note that many caterpillars besides swallowtails also mimic bird poop.)



October 10th. 












October 11th.



October 14th.












October 17th.  The caterpillar is suspended by a silken "belt" and button of silk at the tip of the abdomen.















October 18th.  The transformation.  Still images animated at three speeds: 15 frames per second; 2 frames per second; and 3 seconds per frame.



October 18th.  Key images from the video. 
2:10 PM.  No apparent changes externally except that the prolegs are shrunken.



2:40 PM.  Shortly before this photo, the caterpillar had straightened out and begun to vibrate, presumably to detach the old skin from the new one.  In this photo, you can see that the prolegs have moved posteriorly as the skin at the hind end has shriveled.  The white bands on the side are tracheal linings being drawn out and back.



2:40 PM.  The old skin behind the head has just begun to split.  You can just see a bit of the chrysalis emerging.



2:41 PM.  More of the chrysalis is visible, and the thoracic legs are being pulled further back.



2:43 PM.  The head is now almost free and the old skin is about to slip under the silken support loop.



2:43 PM.  Someone (I wish I could remember who - it was a long time ago!) described the process of sheeding the skin as equivalent to a woman removing her pantyhose without using her hands.



2:44 PM.  Head, antennae, and wings are now visible.



2:46 PM.



2:46 PM.  Wriggling to attach the cremaster (tip of the abdomen) to the button of silk under it.  At the same time, allowing the cast larval skin to fall away.



2:46 PM.  At this point, note how little of the abdomen is in contact with the stem.  That's about to change.



2:52 PM.  Activity has slowed down, but over several hours, the shape will change subtly.



3:28 PM.  The wings have grown larger and the body is arched backwards a bit.  Also, the abdomen has broadly molded itself to the stem, an element of the developing twig mimicry.



5:03 PM



October 21st.  The chrysalis has matured and hardened, slightly changing shape and color.  Note how...
...the abdomen appears broadly attached to the stem (but isn't, really);
...there are green specks resembling lichen or algae; and,
... the surface itself is craggy like a dead bit of twig.






Finally, note how the tip (head end) appears broken off with dark "annular rings" at the center.  As good as this broken twig mimicry is, imagine if I had provided a more mature Common Rue woody stem!



October 26th.  No significant changes.












November 18th.  No changes in the chrysalis.  One month since transformation from caterpillar.  Looks like it will overwinter.



I realigned the specimen to better show the wings, antennae, and legs.






December 10th.  The adult butterfly emerged today.












Note how the dark upper surface scales influence the perceived color of the yellow scales on the underside.


















Too cold for it to survive outside and representing the growing repopulation of Connecticut with this southern species, it will be placed in the UConn research collection for study.



The empty chrysalis.  The old skin split between the antennae and the forewings.



The specimen as prepared for scientific study at the University of Connecticut.


All photos Copyright Stanley E. Malcolm, 2014.  Permission for non-commercial purposes is generally allowed after contacting Stan (stan "at"  Commercial use at higher resolution is available for a reasonable fee.