Santa Clarita and Northern Los Angeles County Area
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Walter's Silk Moth [Saturnia walterorum] Rearing Images

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On 3-24-2006, I made a trip to Magic Mountain (not the theme park!) with a scenting female in hopes of finding wild males on the wing. I was happy to find them flying strong, with about 9 males arriving during a 90 minute calling period. By noon I figured the females would be flying, making their ovipositing runs, so I staked out a likely stand of Manzanita and watched. After about 30 minutes, what looked like a funny-flying, light-colored Monarch flew into view, making stops on various Manzanita bushes as it passed. I was not able to net her, but I did manage to find one of the ova she left. Pic below. Unfortunately, this egg dried-up and died for some reason.

Here are some shots of one of the very fresh males which came to the scenting female... 3-25-2006

I had hoped to get a few more days of baiting wild males with the calling female. However, by 3-27-2006, the weather had still not improved so I decided it was time to let the scenting female (now about 5 days old) and the male get together. This turned out to be pretty easy. I had found that Saturnia males are not always the best at locating a scenting female in a small cage - they tend to fly towards the light source instead of the female, so I decided to try holding the male by his wings and placing him directly on the female. He seemed to get the idea right away, and instead of flying away he grabbed hold and immediately started trying to couple with her. She seemed ok with this and before I could set the two down they were hooked-up.

I didn't want to disturb them since things were going so well, so I just held them carefully and snapped a few pictures. Saturnia don't stay together long and after about 5 minutes they seperated on their own.

The previous week I had watched a wild female's behavior in the field - pretty much continuous flight with ocassional stops to drop only one or two ova before immediately moving on to the next spot. When in a large stand of host, moves of only 15-20 feet between ovipositing stops were common.

In the lab, things are much different. About 90 minutes after mating, the female became active. She began vibrating to warm up, and then started typical (captive) ovipositing activity, which includes a lot of crawling and fluttering, followed by a few minutes of egg laying, a bit (perhaps 5-10 minutes) of rest, then the cycle starts over. I managed to get a few decent shots of her ovipositing. 3-27-2006. By the end of the day, she had laid all her eggs and even though she had energy left and became active on subsequent days, she had nothing left to oviposit.

The female laid 143 eggs, which began to hatch 23 days later. The larvae were placed on mature (old, tough growth) Manzanita leaves, which they ripped into immediately. A couple of weeks later, heavy new growth began and was provided to these 2nd instars on 5-4-2006. They grow rapidly under warm protected lab conditions and are quite hardy. A few of the very young larvae had died-off shortly after hatching, but from that point onward losses have been virtually zero.

The host cuttings are placed in a tub of water through small holes cut in the lid to prevent the larvae from crawling inside. The whole assembly is placed into an ice cream bucket to help catch any frass and fallen larvae, but is not otherwise enclosed. The larvae seem quite happy to stay on the plant and eat. They don't mind being crowded tightly as shown, so long as the host quality is good and the environment is well ventilated (open-air is best). As they approach 3rd instar, they will be sleeved on a larger plant outdoors.

These specimens were supplied by a local collector and are several generations-old captive stock. Not surprisingly, they look a lot like S. mendocino larvae, as the two species are very compatible and interbreed with each other to the north. These images were shot on 6-6-2005 Note the wide variety of color morphs.

The cocoons are also very similar to, if not identical to S. mendocino. Although many texts list the crotch of twigs and small branches as preferred cocoon sites, many of these sleeved larvae chose to spin-up in clusters of leaves at the end of branches. The sleeve over the branch may have helped create un-naturally dense areas of leaves for the larvae to choose over a crotch in a branch.

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