Anrtheraea polyphemus, Selective Breeding
by Bill Garthe.

In May of 2019, Bill Garthe sent me a series of images, courtesy of Nathan Boob, of very dark Antheraea polyphemus specimens. He indicated that the strain came about as the result of some selective breeding. I asked Bill if he could provide a writeup for posting on WLSS. Below is his reply.

Antheraea polyphemus "black" males,
courtesy of Nathan Boob, via Bill Garthe.

Eight dark brown-grey males and females highlight the differences between the "new" darker strain and a more typically patterned/coloured moth. The dark specimens seem to have lost all traces of red or pink in their markings. Bill Oehlke

Hi Bill, Just got the story from Nathan Boob who did the discovery and further breeding of these moths. Here it is copied in Bold from his email to me from tonight.

“On June 2nd, 2013 a dark male emerged from one of my sister's cocoons. The following day, another dark male and three dark females emerged.

My sister had received ova from me (Union co. PA. origin) the two previous years in 2011 and in 2012. She used one of her reared females to attract a wild male at her house, which is about 400 yards down the road from me. All those adults were normal colored and had originated from normal coloured stock. Their offspring (only 12 reached adulthood) were reared on Silver Maple with the first dark male appearing in 2013.
"The first dark adults were small and the females carried small compliments of ova.

"Initially I paired both dark males with all three of their dark siblings. Those pairings yielded 100% dark offspring. They were reared on Pin Oak and the resulting brood in 2014 were much larger than their parents. The females still carried small compliments of ova, one only about 60. I started pairing the females with the most ova to the largest males and within a few generations I was able to breed out that undesirable trait. To this day the females carry full compliments of ova.”

Antheraea polyphemus "black" male and female in copula,
courtesy of Nathan Boob, via Bill Garthe.

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Here is my (Bill Garthe) interpretation of the genetics of the black form polys. I came to this understanding after hearing the generation details from Nathan’s work.

"Normal polys, being tan, have two dominate genes for phenotypic expression for tan. I’ll call them TT. A black poly has two recessive genes for the phenotypic expression of black. I’ll call them tt. When pure recessive parents (both black tt x tt) are crossed, the resulting offspring are all tt and are black.

"Finding a black to start with is indeed rare and has statistically negligible odds, for several generations have to be involved within the same gene pool to result in a black specimen. When a pure tan is crossed with a pure black, the offspring are all Tt, or hybrid in color. These are all going to be tan, but carriers of the recessive black gene. When these hybrids are crossed (dihybrid cross Tt x Tt), 25% will be TT tan, 50% will be Tt tan, and 25% will be tt black.

"It might seem logical to only mate tt with tt, but after several generations of tt x tt inbreeding, the strain becomes weak ..... cripples as adults, little or no fertility, and even cocoon deaths. So, every so often, the tt black has to be outcrossed with a TT tan to revitalize the gene pool. This sets the breeding back three generations as an out cross of TT tan (fresh wild stock) with a tt black results in all offspring being tan Tt hybrids (generation one). Then these hybrids are crossed (Tt x Tt) making for the 75% tan and 25% black (tt) (generation two).

Antheraea polyphemus (orangey) TT female and "black" tt male in copula,
courtesy of Nathan Boob, via Bill Garthe.

Antheraea polyphemus "tan" male and "black" female in copula,
courtesy of Nathan Boob, via Bill Garthe.

Note that the 75% tan are undetectable as either TT or Tt, so these are relatively useless. Now, however, one is ready to cross tt black with tt black from the 25% of blacks from generation two making 100% tt black offspring. This is generation three.

"My moths from last year were wonderful, but very weak having been inbred for several generations. Of the 150+ tt ova I received, only abt 40 were decent with a mere 12-15 being truly A1. I had many many cripples, some decent with minor imperfections, and not one of my attempted pairings panned out along with many deaths in the cocoons. Btw....I tried several variations of mating using hand pairing, normal calling in different conditions, and even hand pairing with headless males....all to no avail.

Antheraea polyphemus tt black males and females and TT specimen,
courtesy of Nathan Boob, via Bill Garthe.

"I hope my input about the genetics is not confusing or frustrating. After writing down the details of Nathan’s discussion, it became quite clear to me how it works. Being a retired biology teacher helps. Nathan agreed/confirmed my Tt stuff. Also, I’m sending Nathan a CC of this just to be sure I presented things correctly on the genetic generational material. Nathan said he’ll send pics of the original blacks. When I get them, I’ll FW them to you.

"Sorry this was so long, but I’m trying to be thorough and respectful of the great job Nathan did with this unusual form. "Take care,

"Bill".

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Bill Garthe: "Some might wonder why I’m so sure abt the crosses. Since none of the offspring have ever exhibited “blending” where a pair of genes share the genetics resulting in a part black and part tan moth, the trait is controlled by a single gene. Had the black gene been dominant with a dominant tan gene, there may have been “co-dominance” or blending if this was a multiple gene trait. The same would hold true for recessive gene sharing. After Nathan’s many generations with the same results, it is evident that it is a single gene trait ..... much like Gregor Mendel’s work with tall and short pea plants. The work with pea plant flower blossoms illustrated the blending factor where more than one gene controls a given trait ...... Dominant Red gene meets Dominant White gene, making a hybrid blended Pink blossom showing co-dominance. Interestingly, crossing the two pinks will once again create some reds and some whites along with pinks.

"Hey ..... got abt sixty black polyphemus to enclose last year and am going for another round this year if ova are available. Can send numerous pics if you like.

"I am rearing Speyeria cybele krautwurmi, S. idalia, and S. diana at the moment which is the only insect stuff happening. Our spring has been terrible ..... just last week, we had six inches of snow. Hope to do more traveling this summer to black light.

"Btw.....a ways back I sent these pics of my gynandromorph polyphemus. I have searched the world over and have not found another gynandromorph of this species. It might be of interest at your site. Maybe u lost my past email....don’t know. It was caught in Unicoi Co., TN on July 29, 2017. Not trying to bother you, just wanting to share if u r interested. Hope all is well, Bill.

Below is a more typical "tan" polyphemus from Prince Edward Island, Canada.

Antheraea (Telea) polyphemus (Cramer, 1775). Photo by Dan Mackinnon.

Some specimens can be a much brighter reddish orange as per the specimen below.

Antheraeapolyphemus female, Montana,
courtesy of Patrick White.

I rear thousands of Saturniidae each summer on Prince Edward Island. I retain about twenty large polyphemus cocoons from my own brood stocks and occasionally purchase cocoons from other breeders.

My cocoons are stored in airtight ziplock tubs in my refrigerator crisper from October until May.

The female below surprised me. I first noted dark gray colouration of the sides of the thorax and abdomen and then observed the large ocelli and dark scales when the moth opened its wings.

Antheraea polyphemus, melanic characteristics, Bill Oehlke, June 2003

I do not know if this moth emerged from local stock or from a cocoon purchased elsewhere.

I placed the female in a "calling cage" and was able to get a subsequent pairing and viable eggs. Larvae progressed as per normal polyphemus and were just about ready to spin when we got hit by a hurricane and torrential rains that lasted for about a week. My sleeves were severely damaged and combination of wind and bird damage resulted in my loss of the entire crop. My only hope is that some of the caterpillars escaped from the shredded sleeve at night (not eaten by birds) and have cocooned and will be seen during normal flight season in June-July of 2004.

Unfortunately I have not seen any more melanic specimens as of June 6, 2019, in my area, but I keep looking.

I usually overwinter rather small numbers of cocoons of each species for breeding stock. Perhaps I will hang onto larger numbers just to see if anything unusual/exceptional emerges with the idea of selective breeding to ensure the different characters (size, colour, pattern) arise in greater numbers.

Steve Ife is currently 2019 going to see if he can capture the genetic code for multiple ocelli from the female below.

Antheraea polyphemus female with extra ocelli,
May 29, 2019, courtesy of Steve Ife.

Another advantage of hanging onto more cocoons and carefully examining specimens is the propect of encountering a gynandromorph such as the pne Bill Garthe discovered below.

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