Antheraea polyphemus Experiments and Observations

by Alan Lee, northern Alabama

Comments by Bill Oehlke: Alan Lee of Alabama had considerable success rearing Antheraea polyphemus during the summer of 2007.

In many of the older texts there were statements that Antheraea polyphemus was single brooded in the northern portion of its range (southern Canada) and double brooded in the southern portions of its range (Florida, Texas, California, etc.).

More recent studies and extensive collecting over a few decades (Vernon A. Brou Jr.) seem to indicate that there are as many as five broods annually in Louisiana. I often receive images of live Antheraea polyphemus moths observed in natural settings in Florida in January-February.

Dirk Bayer of southern Alabama provided some interesting observations on Callosamia securifera cocoons that he overwintered. The moths from sibling cocoons, treated exactly the same way, followed an emergence pattern that would suggest multiple broods when the source cocoons were from the same brood, i.e., some cocoons emerged in the early spring, while others from the same brood did not hatch until summer.

Alan Lee is going to do some experiments with his "overwintering" stock that may yield some interesting results. Alan sent me a letter explaining his plans for 2008 and his observations. My comments (in red) are interspersed amongst Alan's observations, plans and questions.


"Hi Bill,

"On January 3, 2008, I brought down my last sleeve of 2007. I had been watching them (Antheraea polyphemus larvae), and they were really big. I wanted to leave them out as long as possible. The low for January 2 was 27 F. The low for January 3 was 18 F.

"When I opened the sleeve on January 3, around 10:30am, the temperature had warmed to about 25 F, and all was as I expected. Some cocoons would be complete and the remainder of the caterpillars would be dead. There were fourteen complete cocoons, three translucent cocoons, twelve green caterpillars and one brown shriveled caterpillar.

"Of the complete cocoons, eight shook freely. Those eight had probably pupated prior to the cold. Pupation of the others had not happened yet. The caterpillars seen through the translucent cocoons were motionless but soft when pressed.

Of the twelve green caterpillars, five were soft and pliable and drooped over when held by one end. Seven were rigid as though frozen solid. They remained stiff when held up by one end and were "solid" when pressed. The shriveled caterpillar was discarded.

I kept the torpid, frozen caterpillars and took them home to show my wife and kids. After they had examined the larvae, I placed the caterpillars on the table to later feed to the chickens. Then the excitement began."

At 11:30 am, when I picked up the box of "frozen" caterpillars to take them outside, I noticed some movement. And sure enough, five of the caterpillars were intentionally crawling around! On further inspection, four others would flex to touch and three remained motionless. I checked the translucent cocoons, and even one of the encased larvae had resumed its spinning.

"I had heard fishermen say they would place catalpa worms (caterpillars) in the fridge the night before they went fishing, saying it made them easier to manage. They said they all "came back to life when they warmed up." So maybe polyphemus are the same. But 18 degrees is much colder than a fridge--that's a freezer!! So I placed a limb of oak over them and continued to watch. The notes below indicate how things progressed.

"Noon: Five had climbed up and were clasping limbs of the oak; five others would flex to the touch and two others remained motionless.

"12:10: Five were searching on the limbs, and the other seven would all flex to the touch.

"12:15: Five were searching, two more had climbed up and were clasping, the other five flexed to the touch.

"12:20: First frass dropped.

"12:30: Two more had climbed up and were clasping: now five were searching, four clasping, three crawling around.

"12:45: All twelve either clasping or searching in th eoak -- no eating noted. I checked the translucent cocoons and all three had enclosed larvae moving withone visibly spinning.

"3:00: Five caterpillars had dumped and were spinning up in the oak; one was eating; six were clasping very still.

"5:00 pm: Now three were eating, five were spinning and four were clasping.

"I went to work (night shift) and did not check again until morning.

"January 4: 8:00am: All translucent cocoons were opaque, five nearly complete cocoons on the limb, one beginning to spin up, four eating and two just clasping.

"Jan 5: 8:00am: six complete cocoons, two spinning, four eating

"Jan 6: 8:00am: eight complete cocoons, one spinning, three eating

"Jan 7: 8:00am: ten complete cocoons, one spinning and three eating

"Jan 8: 8:00am: eleven complete cocoons, andone had fallen off and was brought to me by the dog. It was dead.

"Jan 25: All fourteen cocoons from the original three translucent cocoons and twelve larvae seem to have good weight and sound during hand heft and shake test.

"I do not know if anyone has sent you any similar experience so maybe this wil be a good one for the website. Will they have different colours due to the cold exposure? I think I have read that some species have shown colour changes in response to cold exposure.

"If these do eclose and prove to be sexually viable, if there are colour changes, will these be passed on to the next generation?"

Many thanks to Alan for an interesting and well written article. I am quite surprised that the larvae which appeared to have been completely frozen were able to resume moving, feeding, spinning and apparently pupating. Perhaps because this was a fall brood, enzymes were already present in the larvae, preparing them for winter diapause, that would enable them to endure such cold. I am not sure that there would be a similar "resurrection" if summer polyphemus larvae were exposed to the same cold, artificially or otherwise.

It will be interesting to see if there is a colour change or if there are any other apparent differences.

If there are differences, I do not think they would be transmitted to subsequent offspring, as I do not think there would be any changes to DNA, but that remains to be seen.

Moths emerged from all of the cocoons of the "frozen" larvae. All cocoons were taken out of cold storage at the same time, early May, and placed in the same eclosion cage. The first moth emerged in mid June. Other eclosions were very sporadic throughout summer and some moths did not eclose until late July and even early August. There did not appear to be any difference in the appearance of these moths.

The sporadic eclosion pattern is a mystery!

Plans for 2008

"1) To expand the species that I raise to include cecropia, sepulcralis, and maybe regalis (if I get some to the lights)
2) To expand butterfly plantings
3) To make this a family project that will bring some sort of income
4) To continue to learn and have fun in the process

"We spoke before regarding the lack of information on southern region true diapause and how more information is needed. I hope that I understood and have done correctly.

"I have divided all my polyphemus cocoons into groups to determine eclosure times. I have ten groups (labeled A - J) based on date spun up and whether we raised on cut or sleeved leaves. These groups were further divided into three groups: one group placed in the fridge, one group placed in the barn, and one group kept in the house.

"To date I have placed 537 cocoons from November 23, 2007 to January 9, 2008. They were placed (northern Alabama) as follows:

276 - fridge
183 - barn
78 house

"I check daily or every other day for eclosures and record date, group, and sex of all eclosures. Since first placement on November 23, I have had 22 eclosures as of January 10, leaving me an inventory of 515 polyphemus. I also have sixty lunas grouped the same way. I will continue to monitor these cocoons for eclosures until they are all finished. I will release many of them, but wil keep anything that might look different. If any do not eclose, I will open them to see what is inside the cocoons.

Wow! That is a large number of polyphemus cocoons. Congratulations on a very successful fall rearing campaign. I suspect the ones (twenty-two) that have emerged so far are the ones that spun up earliest and have been at the more consistently warm temps, probably in the house.

I am sure your recording will be of much use to you and to others. I am very much interested in reading what you observe/learn.

"For the ones in the fridge, I don't know. Here's where I need your advice. I plan to keep a few for me throughout the year in sleeves, maybe one or two (broods??). I want to spend my time with the new species, raising all the cecropia that I can. They will finish up early, at least comparatively early. Then in the fall, I will sleeve up all the poly larvae for which I can find sleeves. Hopefully I will be able to sell some and have plenty left over for 2009."

Here on Prince Edward Island, the four large silkmoths, luna, polyphemus, cecropia and columbia are all single brooded. Once I have harvested them in the fall, I don't have to worry about them emerging until the following spring as long as I keep the cocoons from October til May in my refrigerator crisper. I do not think you can successfully suspend development for a prolonged period unless the moths are single brooded (cecropia and columbia) or unless the cocoons have naturally prepared for a diapause.

In New Jersey where there are two broods and sometimes even a partial third brood of both luna and polyphemus, my father rears relatively small numbers of both species during spring and summer. He keeps a few cocoons from the first brood to rear much larger numbers of those cocoons which he exects to diapause during the winter. The reason for this is simply marketability. First brood lunas can eclose within two weeks of spinup during a warm spell. We usually do not have a large market for summer lunas/polyphemus, and they would have to be sold very quickly so they would not be eclosing in the mail. Diapausing cocoons/chryslids/pupae can be sold at a much more leisurely pace from October until April even into May if they are kept cool.

Your decision to rear large numbers of the single brooded cecropia, I feel, is a good one. Once they have cocooned you will have about nine months to sell them. It wil be great to find out what transpires with your local lunas and polyphemus.

"This spring I will have about 200 potential females to call, mate and lay eggs. Only needing one or two for myself, I will hopefully have lots of extra to sell (as dried specimens ??).

"1. I can remove fridge groups at staggering times, recording eclosure dates and sexes as before. That way we will know how many survive the refrigeration (diapause).

"2. Then I can allow all the females to call and mate. That way, we know if the refrigerated cocoons perform normally.

"3. Then I will watch all the eggs to see if they hatch. To see if the refrigerated cocoons are fertile.

All are great ideas and should provide very useful information. Hopefully a high percentage of the cocoons that you have put into cold storage (refrigerator) in November will successfuly overwinter, eclose in the spring, mate and lay fertile eggs. If not, you will have to make adjustments to any marketing strategy.

"If I understood correctly, that was the information we needed to determine the effects of diapause (induced diapause) on my cocoons and viability of the cocoons I would be offering for sale. I hope I got it right."

Yes, the info will be very useful.

Now, for what I will have available for sale: I hope I am not being presumptious in planning to be able to sell something this year (when?). If so or if I have not understood, please let me know."

This year I reared approximately 750 polyphemus to diapausing cocoons. Many I sold in Canada and many I shipped overseas. Most of the cocoons that I sold in the United states were cocoons that were reared by experienced breeders in the U.S., and most of those naturally diapausing cocoons were shipped by the breeders in the fall to my U.S. shipping partner in New Hampshire.

If your cocoons are successfully diapausing and are of good size (sleeve reared material is generally prefered over stock reared on cut food), then I would be prepared to purchase them in bulk, with you shipping them to my U.S. shipping partner.

I do not want to set anyone up for a big disappointment. I cannot commit to purchasing large numbers of cocoons in advance. Last year I believe I purchased about seven hundred lunas, five hundred cecropia and five hundred polyphemus cocoons from experienced U.S. breeders for distribution in U.S.. Some years there are research projects for polyphemus and there is a much bigger demand than in other years. last year one customer ordered five hundred polyphemus. This year the largest single order for polyphemus by one customer was three hundred cocoons.

I cannot make a promise to you that I will buy all of your polyphemus cocoons in the fall.

I am prepared to include you in the group from whom I make purchases and I would try to spread those purchases around evenly. If there is a really big demand for polyphemus, then I might end up purchasing all of your stock and still not have enough. if there is a smal demand, then I might only request 100 cocoons. I would want you or anyone else to be aware of those possibilities. I advise all that they should be prepared also to market their own supplies.

I would be very happy to refer any spring summer requests I get for non-diapausing cocoons to you, but I have not tried marketing non-diapausing stock before. I suspect there wouldbe a much much lighter demand, but some requests definitely do arrive.

I am also quite prepared to work wth you as an egg subcontractor. To me there are real advantages for customers to purchase livestock close to their own region. Most of my U.S. orders for eggs come from more northerly state where people do not have leaf out until mid April or even mid May. Hope you understand that I cannot guarantee anything. Usually there are regular orders for eggs and for cocoons throughout the spring and summer (eggs) and fall and winter (cocoons).

If you are committed to producing quality non-diapausing stock, then I would change my website advertisements to include same, and you could work as a subcontractor for summer stock, and be prepared to start marketing on your own if no orders arrive to me.

Marketing is not always easy. Here is an actual correspondence that arrived here earlier this evening. My reponses are below each question.

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What do you recommend, for someone like me who hasn't done this before?
I recommend you start off slowly maybe with four cocoons each of two different species, any two would be okay, but I think the lunas and polyphemus would be best. You might even consider eight cocoons of just one species.

How many cocoons should I get?
Minimum of four of each species that you want to try.

I think I'd like to have at least one each (of polyphemus and cecropia), but is that too few?
We try to ship roughly equal numbers of males and females. If you order only a single cocoon, you might not get a female. If you order only two cocoons you wil likely get a male and a female, but they might not hatch out at the same time, so the more cocoons you have, the better your chances of having both genders out at same time for pairings.

Should I have two of each, or even more?
You might even want to try just one species in which case I would suggest the lunas.

About how soon after I get them will they hatch?
Please read about two dif methods of cold storage at http://www.silkmoths.bizland.com/bonniecocoonordersa25October2007.htm

The moths don't eat, right?
Correct

But how should I provide water? Cotton wool? Little pans?
They do not drink either as they have no mouth parts or feeding tubes. They live off fats stored from caterpillar days.

What should I use to make a container that the males can get into, for breeding?
Make a cylinder out of 3/4 inch hardware cloth. Once you have received cocoons, I wil send you an image of a cage with instructions.

If it's big enough for the males to get in, can't the females get out?
Males don't get in, they are able to mate with the females right through the openings in the hardware cloth cage. Also unmated females usualy do not fly for the first two or three nights after they have emerged. They save their flight reserve energy for depositing fertile eggs. Therefore they do not usually fly until after they have mated. You can put them in a cage with an open door and let the males fly in without having to worry (usually) about the females flying away.

Or can they mate through screen?
Yes, through the hardware cloth mesh.

How can I protect them all from birds?
Don't put cages out til birds have retired for the evening. Wait up til moths have paired or set your alarm clock and get up before the birds do. Quite fascinating to watch the males fly in.

(I have feeders out now -- but they're mostly for finches and seed-eaters. Are there any bigger birds that love to eat the big moths?)
Almost all birds love to eat moths, butterflies and their caterpillars.

Can you tell, from the cocoon size maybe, which ones will be female?
Usually the heavier cocoons are females as they are carrying a payload of 250-350 eggs and need the extra energy reserves for flight, but we don't sell just female cocoons.

If males hatch, should I just let them go, so they can find wild females?
You can let them go or leave in cages with females. They usually are more prone to mate (especially polyphemus) if they actually fly in to the calling females. For that reason, I often release males just after dark (protection from birds) on nights when I have females in the cages. The males will either mate with wild females in your area or wil fly into your calling females.

Clearly I need some "online support." :)
Will do my best to answer further questions.

But I'm definitely ordering some. I just want to make sure I'm prepared to take the best care of them when they get here.
Also a good article to read at http://www.silkmoths.bizland.com/emerge.htm

Thanks!!

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Some sales are quick and easy. Other times much time is spent answering questions for a small order or just helping someone out.

"In 2008, I will have eggs for sale, when available, several times throughout the year. (I will keep some eggs from each batch sold to verify fertility.) I will have larvae for sale, when available, several times this year. I will have spring, summer, and fall (non-diapause) cocoons for sale, and, depending upon the results of our study, I will have late season diapausal cocoons for sale. Is that right?"

I will try to market eggs for you where you work as an egg subcontractor. That is, I try to market eggs in advance, you advise me when you have eggs ready, I advise commited and potential customers that eggs are ready, to see if they are ready to accept the eggs. Maybe yes, maybe no!

For those customers ready to receive eggs, I forward to you the shipping address and quantity and species via a website with printable address labels that you can print, cut out and tape to package with eggs that you ship at agreed to rate. I answer all the questions. You gather and ship eggs. I keep tabs of your running total on website page with address labels where you can double check it. Then I hope customer sends me payment. I send you your share once every two months or so provided eggs prove fertile. I also send you instructions about how to ship eggs safely.

I do not try to market larvae as I find that shipping tends to stress them.

Sale of non-diapuasing and diapausing cocoons as explained above.

"I can keep you updated by email about what is available and how things are going.

"If I have all this correct, I will need to know when to have the first eggs available. That is, what schedule you suggest I follow I follow for removing my cocoons from the fridge. I will be doing this anyway for our study. But I wil need to know when to begin having eggs available. I can sell all the eggs I can. I wil need to know how to ship them. I can sleeve up all I want to keep. Then I can "seed" al the oak trees in my area with the rest."

Orders could come in at any time, so I cannot advise you as to when the first batch(es) might be needed. Here, to spread out my rearing season and to have eggs available at different times, I stagger the times when I take the cocoons out of cold storage. Therefore I usually have female polyphemus emerging form very late May into early July. I would suggest you also try for a staggered emergence pattern. Releasing a gravid female is much easier than seeding out larvae. Polyphemus cocoons coming out of cold storage, will usually emerge in 25-29 days if stored at room temperature indoors, longer if it is cooler, shorter if it is warmer. That is my experience here. Because the natural photo period is much longer where you are than it is where I am, your development times might not takeas long.

More to come!

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