The Birds and the "Bugs"

For many years I have had great success rearing large numbers of Saturniidae outdoors in sleeves. During the summer of 1999 I reared over 3000 Antheraea polyphemus in close to one hundred, twelve-foot-long sleeves made out of the lightweight, spun-bonded remay cloth that is often used to protect garden crops. Image courtesy of Leroy Simon.

The remay was perfect for my needs as it was tough and extremely light weight, allowing good air circulation and sunlight penetration.

For the polyphemus, I would bend over a fifteen to eighteen foot tall white birch tree and hold it down with one hand and pull the sleeve over the foliage with the other.

Once the tree was capped, I would release it to its upright position and insert the larvae and then tie off the bottom of the sleeve. Little work was required thereafter, except to periodically open the bottom and empty frass. With thirty-five to fifty larvae per sleeve, I usually only had to move the larvae twice (sometimes thrice), once to the original tree and then a second time when the first tree was defoliated.

It was in midsummer of '99 that I had my first encounter with two immature blue jays that had torn through my sleeve material and were feasting on the mature polyphemus therein. Either they could not find their way out, or my presence put them into a panic. I opened the bottom of the sleeve, bent the tree down and removed the sleeve to get rid of the birds as they would not fly out through the tear in the side. Once the birds were gone, I was lucky to find just a few larvae. Most had been eaten and there was bird "frass" widely distributed on the bottom of the sleeve. They must have been in there for some time.

Photo courtesy of Michael Myers

I did not have any more problems that summer with birds tearing through the sleeves, but I did notice some of my larvae were being pecked at and eaten through holes pecked by birds roosting on the top of the sleeves. Fortunately, I was only loosing a few larvae, the ones that ventured to the upper reaches of the foliage.

I was not so lucky during the summer of 2000, however, when it seemed that just about every one of my polyphemus sleeves was being torn and entered by birds. I lost hundreds, possibly thousands, of mature polyphemus larvae that summer. I do not know if it was the same bluejays or another species, but it was most depressing to see the torn empty sleeves when I would go to harvest cocoons. For some reason, the birds did not bother the other species I was rearing. I brought what I could find of the polyphemus indoors and had some success.

I decided I would try two different approaches in 2000: I bought many rolls of fibreglass screening and sewed up big sleeves to go over the top of the remay sleeves, and I also purchased large quantities of birdnetting, the type often used over fruit trees to protect crops from foraging avians.

I would tie the birdnetting together with string every five to six inches through the 3/4 inch mesh to fashion large sleeves to pull over remay. It would take me close to 45 minutes to tie up each sleeve.

Fibreglass screening and the birdnetting brought considerable extra expense to my operation and also required considerable time so I worked with larger numbers of larvae in fewer sleeves. Sleeves had to be changed many times due to the increased numbers of larvae enclosed.

I planned to only protect the polyphemus as the other species had not been bothered the previous year. I soon changed my mind when one of my luna sleeves was attacked.

The bird netting over remay worked best, but even then I had some problems with birds landing on smaller horizontal sleeves or on the top of my large sleeves. The birds were able to tear right through the fibre glass when it was not protected with netting.

A few of my columbia cocoons were pecked at through the netting and remay near the bottom of the sleeves. Fortunately the birdnetting is very tough and durable and can likely be used for many years.

To try to totally eliminate losses for 2002, I will cover all sleeves with birdnetting and fasten some sponge material to inside of netting to keep it some distance from remay, at least on any horizontal surfaces. I will also wrap the bottom of the columbia sleeves with old material to protect cocoons spunup near base of sleeves.

I continue to use the remay as it offers excellent protection from parasitic wasps, hides the larvae somewhat, and also traps heat, hastening development in this relatively cool northern environment. It is also easy to work with and relatively inexpensive.

I think I have my current predator problems nearly solved, but the next villain may require still yet another approach.

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