DISTRIBUTION:

The polyphemus moth (Antherea polyphemus) is North America's most widely distributed large silkmoth (wingspan up to 6 inches). Native populations exist in all U.S. states and Canadian provinces except Alaska, Arizona, Hawaii, Nevada, and Newfoundland.

David Tilden reports a polyphemus in Fort Smith, Northwest Territories, Canada, in June, 2011.

Antheraea polyphemus male, Trenton Ontario, May 27, 2009, courtesy of DSG.

These moths are quite common here on Prince Edward Island, Canada, despite being listed as absent from this province in an excellent resource, The Wild Silk Moths of North America, by Tuskes, Tuttle and Collins.

FLIGHT TIMES:

In Canada and U.S. border states Antheraea polyphemus is univoltine (single brooded). Most adult moths fly from late May to July.

In New Jersey, the Ohio River Valley, and westward the species is bivoltine (double brooded). Winter diapause stock (pupae that have remained in cocoons over the winter) usually emerges in April or May and second brood adults emerge in July or August.

"In Texas and Florida adults fly in every month except January."

On January 25, 2003, I received a report of a pair of polyphemus in Florida. Adult moths were seen in the same area in late November.

On January 30, 2004, in Palm Bay, Florida (Brevard County) a female polyphemus was observed at a laundramat by non-member Joan Molozaiy (even the moths have to wash their socks!), so it would appear this species is on the wing all months in Florida, and probably in south Texas too!

Ron Votaw reports a wild male, March 10, 2008, Comal County, Texas.

Eggs from the female polyphemus reported above on January 30, 2004 have hatched, so there had to have been a wild male on the go as well.

Vernon Brou reports that there are five peak flights in Lousiana at 47 day intervals from mid-March through September.

On January 30, 2003, I received a report of an outdoor polyphemus emergence from Baton Rouge, Louisiana on January 29. I suspect there is at least a partial sixth brood in La., or changes in weather patterns are creating changes in flight seasons.

Click to the right for an ongoing report of polyphemus flight times.

Fourth instar caterpillars experiencing sixteen hours of daylight/day progress directly from larvae to pupae to adult moths while those fourth instar larvae that experience only twelve hours of daylight/day enter a pupal diapause that will take them through the winter months. The diapause will be broken by increasing hours of daylight and warmer temperatures. Hence springtime weather conditions will determine whether there are one, two, or three or more broods in a given year.

Even in New Jersey there is sometimes a partial third brood. Males tend to emerge two to three days before females.

Here on P.E.I., Canada, cocoons removed from cold storage (refrigerator crisper) in spring produce adults in twenty-one to twenty-eight days when kept at room temperature (24-25 C or 75-77 F).

Stock that has been exposed to cold and then warmed will emerge out of season. Pupae that would normally diapause in the fall under cold conditions will emerge prematurely (as far as the weather goes) if stored under warm conditions.

ECLOSION:

The adults tend to eclose or emerge from their cocoons in the early afternoon.

The adult secretes a chemical called cocoonase to break down or soften the sericin that binds the silk strands of the cocoon. Hornlike projections at the base of the forewing are then used to tear at the silk while strong legs continuously heave the moth forward until it can escape from its valveless cocoon. Photo by Dan MacKinnon with inserts from Kurt Himmelbauer.

This event sometimes creates a racket in an indoor emergence cage, but the process usually only lasts a few minutes. The moth must now climb up the side of its emergence cage or up a stem or tree trunk so that its wings can hang freely while fluid is pumped into the numerous veins in the wings. After about twenty minutes this "inflation" process is complete and the wings soon stiffen in preparation for flight. Males tend to fly shortly after dusk. Females seldom fly until after mating.

SCENTING AND MATING:

Females begin releasing their pheromone, a 90:10 mixture of chemical attractant consisting of 6 cis-11-hexadecadienyl acetate and trans-6, cis-11-hexacadienal aldehyde, at approximately 10:00 pm and continue scenting until mating or around 1:00 am. Unmated females scent again just before dawn. The scent gland protrudes from the posterior end of the abdomen.

Photo courtesy of David Wilbur.

The same gland is used to expel and affix sticky eggs to the undersides of leaves.
Flying males zigzag into the wind to locate the female scent plume with their highly developed antennae: 60,000 sensilla and 150,000 receptors.

The female moth pictured on the left has much smaller antennae than the male to the right. The color differences are not typical of gender, but merely of variations within the species.

Photo courtesy of M. Whitmore.

Photo courtesy of Dan MacKinnon

Males can only fly in temperatures above 7 C or 45 F and have been known to fly many miles in a single evening. Colder temperatures prevent the males from thermoregulating body temperatues by vibrating the wings. This species mates readily in captivity, even in small cages (one cubic foot) according to some texts, but I have not found this to be so on P.E.I. Almost all of my matings occur when wild males fly in to my caged, scenting females. I seldom get pairings with males in the cages.

Once paired, the couple tend to stay paired until the following evening. A single mating will fertilize all of the 200-350 eggs. Males may mate again, but ova may not be viable. Sperm in the female receptacles triggers ovulation responses, but even unmated females begin laying eggs after two or three evenings.

Antheraea polyphemus male, Hampton Beach, Virginia,
courtesy of Jurgen Vanhoudt.

Antheraea polyphemus female, Hampton Beach, Virginia,
courtesy of Jurgen Vanhoudt.

Antheraea polyphemus hatchling, Hampton Beach, Virginia,
courtesy of Jurgen Vanhoudt.

Antheraea polyphemus second instar, Hampton Beach, Virginia,
courtesy of Jurgen Vanhoudt.

Antheraea polyphemus fourth instar, Hampton Beach, Virginia,
courtesy of Jurgen Vanhoudt.

Antheraea polyphemus fifth instar, Hampton Beach, Virginia,
courtesy of Jurgen Vanhoudt.

EGGS, LARVAE, COCOONS AND PUPAE:

Relatively large, off-white eggs with a brown band around the horizontal circumference are laid singly or in groups of three to five on host plant leaves. Incubation lasts ten to fourteen days. Emerging caterpillars chew through one side of the the egg. Photos by David Wilbur.

The larvae eat most of their eggshells and spend six to eight weeks passing through five instars as green caterpillars. The large brown heads, typical of polyphemus larvae, are evident even in the first instar. Larvae stop feeding and become quiescent for a day or two before shedding skins to make way for new growth. They should not be disturbed at this time.

Relatively few larvae fasten their cocoons to the tree branch with a peduncle, although this practice seems more common in southern latitudes. In the north more larvae spin cocoons in a leaf wrap that will fall to the ground, or larvae descend the tree to spin up in surrounding grasses. The larval gut is cleared via a loose, runny stool just prior to the spinning of a compact oval cocoon. The larvae secrete a substance that hardens the cocoon.

Ben Trott, who has sent me many outstanding images of Sphinigidae, sends this beautiful image of Antheraea polyphemus feeding on Populus grandidenta in British Columbia, Canada.

Antheraea polyphemus fifth instar on Populus grandidenta,
British Columbia, Canada, courtesy of Ben Trott.

Pupae can be sexed by removing them from cocoons. The outline of the antennae is clearly visible on the pupal shell.

I usually don't remove pupae from cocoons. If I want to sex them or check for disease or parasitization, I will usually just use a sharp pair of scissors to cut a slit across one of the longer axis.

IT IS INTERESTING THAT PUPAE ORIENT THEMSELVES SO THAT THE DORSAL SURFACE IS ALWAYS SKYWARD. IF THE COCOON IS ROTATED, THE PUPAE WILL WIGGLE SO AS TO REORIENTATE THEMSELVES TOWARD THE LIGHT.

In August of 2011 Ryan Saint Laurent reports he found wild polyphemus larvae feeding on Northern Bayberry (Myrica pensylvanica) in Rhode Island.

Myrica pensylvanica

Pupae can be sexed by removing them from cocoons. The outline of the antennae (male) is clearly visible on the pupal shell. I usually don't remove pupae from cocoons as per the picture. If I want to sex them or check for disease or parasitization, I will usually just use a sharp pair of scissors to cut a slit across one of the longer axis. This pupa should be returned to his cocoon or wrapped in loose paper toweling.

Photo courtesy of Kurt Himmelbauer.

IT IS INTERESTING THAT PUPAE ORIENT THEMSELVES SO THAT THE DORSAL SURFACE IS ALWAYS SKYWARD. IF THE COCOON IS ROTATED, THE PUPAE WILL WIGGLE SO AS TO REORIENTATE THEMSELVES TOWARD THE LIGHT.

Photo courtesy of David Wilbur.

Visit Antheraea polyphemus mature larva, Fort Worth, Texas, October 23, 2009, courtesy of Phyllis.

Acer rubrum......... Red maple
Betula papyrifera...... White/paper birch

---

Acer negundo........ Box elder/Manitoba maple
Acer pensylvanicum.... Striped maple
Acer saccharinum........ Silver maple
Alnus incana.......... White alder
Alnus serrulata........ Hazel alder
Amelanchier canadensis.... Thicket serviceberry
Arbutus menziesii....... Pacific madrone
Baptisia tinctoria...... Wild indigo
Betula alba .......... White birch
Betula lenta ........ Sweet birch
Betula pendula ....... Silver birch
Betula populifolia .... Gray birch
Betula pubescens ..... White Birch
Capsicum annuum ....... Cayenne pepper
Carpinus americana .... American hornbeam
Carpinus caroliniana ..... American hornbeam
Carya amara
Carya glabra .......... Pignut hickory
Carya ovata ........... Shagbark hickory
Carya tomentosa...... Hickory
Castanea dentata ........ American chestnut
Castanea pumila...... Chestnut
Castanea sativa .......... Spanish/Sweet chestnut
Castanea vesca............ Spanish chestnut
Corylus americana ......... American hazelnut
Corylus rostrata .......... Beaked hazelnut
Cornus racemosa ........... Gray dogwood
Crataegus coccinea ....... Scarlet hawthorn
Crataegus crus-galli..... Cockspur hawthorn
Crataegus tomentosa ...... Pear hawthorn
Cydonia oblonga ......... Common quince
Fagus ferruginea ........ American beech
Fagus grandifolia ..... American beech
Fraxinus .............. Ash
Gaylussacia dumosa ....... Dwarf huckleberry
Gleditsia triacanthos ..... Honeylocust
Hamamelis virginiana ...... Witch hazel
Juglans cinerea ......... Butternut
Juglans nigra ........... Black walnut
Liriodendron tulipifera.... Tuliptree/White poplar
Malus pumila ............ Apple
Myrica cerifera .......... Southern bayberry/Waxmyrtle
Myrica pensylvanica ....... Northern Bayberry
Ostrya virginiana ....... American hop hornbeam
Pinus ............... Pine
Platanus occidentalis ..... American sycamore
Populus grandidentata ..... Bigtooth aspen
Populus tremuloides ....... Quaking aspen
Prunus cerasus .......... Sour cherry
Prunus domestica ....... Garden plum
Prunus pensylvanica ....... Pin Cherry
Prunus persica ........... Peach
Prunus serotina ........ Wild black cherry
Prunus virginiana ...... Chokecherry
Pyrus communis ........ Pear
Quercus alba ........... White oak
Quercus coccinea .......... Scarlet oak
Quercus falcata ........... Southern red oak
Quercus lyrata .......... Overcup oak
Quercus macrocarpa ....... Bur oak
Quercus nigra ........... Water oak
Quercus palustris ........ Pin oak
Quercus phellos.......... Willow oak
Quercus robar ........... English oak
Quercus rubra........... Northern red oak *
Quercus stellata ........ Post oak
Quercus velutina ........ Black oak
Quercus virens
Rhamnus ............... Buckthorn
Ribes cynosbati ........ Pasture gooseberry
Ribes sanguineum
Ribes sativum ........... Common currant
Salix alba ........... European white willow
Salix babylonica .... Weeping willow
Salix fragilis ...... Crack willow
Salix humilis ....... Prairie willow
Salix interior ...... Sandbar willow
Sambucus ............ Elderberry
Sassafras albidum ...... Sassafras
Sorbus ............ Mountain ash
Tilia americana ....... American basswood/Linden
Tilia europea .......... Common lime
Ulmus americana ...... American elm
Vaccinium .......... Blueberry
Vitis ............. Grape
Weigela ......... Fairy trumpets

Goto Antheraea polyphemus life cycle, courtesy of Jeff Ausmus.

Patrick has also sent a series of beautiful images of Antheraea polyphemus from Montana.

Antheraeapolyphemus female, Montana,
courtesy of Patrick White.

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