Sunday, August 31, 2014

Pandora Sphinx Moth


  Photo by Drew Albert
Drew Albert of our Master Naturalist chapter found this beauty hanging out in a tower of the National Weather Service where he works.  This was a restricted area and it wasn't wearing an ID, but he turned a blind eye and a camera onto the trespasser.

This is a Pandora or Pandorus sphinx moth, Eumorpha pandorusIt seems appropriate that it was hanging out at the airport as it resembles a stealth bomber that is painted in jungle camo, like Mother Nature had been watching too many Rambo movies that day.  They fly predominately at dusk on green to brown wings that can span 4.5 inches.  Their wing shape looks a lot like the somewhat smaller hog sphinx moth.


Hog sphinx, Darapsa myron - Chris Barnhart
Pandorus Sphinx Moth Pupa - Eumorpha pandorus
  Janice Stiefel
The larvae are just as impressive as the adult.  They grow up to 4 inches long by feeding on grape species (Vitis) as well as Virginia creeper.  There is considerable variation in the colors of their various instars.  The last instar climbs down to the ground and burrows into the loose soil.  There it will pupate in the fall, forming the cocoon that will be its home until it emerges next year as a beautiful moth.

caterpillar - Eumorpha pandorus
  Fifth instar - gkmarsh
The caterpillars will go through five molts, called instars.  Early instars have a horn like most sphinx moths, for example the familiar tomato horn worm.  Unlike their cousins, the Pandora's horn has a cute little curl.  This disappears in the fourth instar, replaced by a little eye mark.

Pandorus Sphinx - Eumorpha pandorus
Early instar - Erik Blosser

Pandorus Sphinx Moth Larva - Eumorpha pandorus
 Head tuck - Janice Stiefel*
Like many other caterpillars, their prolegs have special hooks which allow them to feed upside down, clinging to the underside of a leaf to hide from predators.  At times they will tuck their two front segments into the third, giving the otherwise some what pointed head a blunt appearance.  When they are threatened they use a vulture-like defense, vomiting up a sticky substance.

Pandorus Sphinx with parasites and wasp - Eumorpha pandorus

Pandora sphinx with parasites and wasp emerging - Jo Ann Poe-McGavin
It doesn't always turn out well for caterpillars.  In addition to their contributions to the food chain for birds, insects and even snakes, there are various parasites that utilize them as a nursery for their young.  The specimen above is still alive, but just barely.  It was infested by the eggs of a parasitic wasp whose young have just pupated and emerged.  The parasites preserve all the caterpillar's vital functions until the last minute to maintain their food source.  You can see a little wasp at the bottom, presumably newly emerged from the pupa.
 
 *  The late Jan Stiefel had submitted 779 photographs to Bugguide.net and over 129 Door County, Wisconsin moth records, which are documented with the state. She had served as editor of the "Wisconsin Entomological Society Newsletter" since 1999.

There is more information at the  uwm.edu/ website.

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