Missouri Master Naturalists- Springfield Plateau Chapter

Sunday, September 12, 2021

Raising Polyphemus

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 was 10 years ago without a waterproof camera but the shot was 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 giant in Greek literature, it has a single large eye spot on each hind wing.  Wikipedia gives a lot more information on these giant silk moths

A Polyphemus moth caterpillar can eat 86,000 times its weight in a little less than two months!  Chris Barnhart raised them for the Butterfly House and Insectorama, a prodigous task as seen here.

They have 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 below)

Polyphemus male with plumose antennas
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! 

This year the Insectorama was cancelled due to Covid.  With 40 + cocoons and no one to give them too, we distributed them to WOLF School students to raise and release.  One of the students noticed that after emerging, a female moth began laying eggs.  Unmated females will deposit eggs after a while and with their short life span they are unlikely to get a second chance at mating.


These eggs look at first glance a lot like a hamburger, possibly because I am hungry as I write this.  The upside down egg on the right shows the ragged dark ring where it was glued to the surface of the cage.  Thanks go to Kapri for bring me the find.