Tuesday, August 3, 2010

Polyphemus' Perilous Perch

Polyphemus- Click to enlarge
My granddaughter spotted this Polyphemus moth, clinging below a rock shelf by a little waterfall. It was in the shade all day, had a cooling mist off the waterfall and was out of reach to most of its normal predators.  Its wingtips were barely an eighth of an inch above the water but the view must have been worth the risk.
This moth probably was tired after a long night of courting.  Unlike most other lepidoptera, its lacks a functioning digestive system and never feeds.  It exists to breed and lives only six days, so it probably earned a rock with a great view.
Polyphemus, Antheraea polyphemus, is the second largest moth in Missouri.  Named for the one-eyed cyclops in Greek literature, it has a single large eye spot on each hind wing.

Wikipedia gives a lot more information including these facts:
  •  A Polyphemus moth caterpillar can eat 86,000 times its weight at emergence in a little less than two months!  It has several broods between May and August, its caterpillars feasting on 20 different tree species including maple and oak.  The caterpillar usually wraps a host plant leaf around its cocoon. 
  • Males can be distinguished by their feathery antennae,  which are more plumous than the females.  Yes, I know- I had to look it up too- its Latin for "full of down or feathers".  (see photograph) 
  • The females emit pheromones which the male can detect through its large, plumose antennae.  The pheromones are released at a species-specific time, referred to as the "calling time". This “calling time” can help prevent moths with similar pheromone chemicals from finding the wrong mate.  (MDC)  Polyphemus' calling time is between 11 PM and 1 AM, and again from 3 AM to dawn.*   
  • Males can fly for miles in order to reach a female. After the moths mate, the female spends most of her remaining life laying eggs, while the male takes off and may mate several more times.  Editors note: No surprise there!

    Note Feathery Antennae- click to enlarge
    * Butterflies and Moths of Missouri, Heitzman

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