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Post by Crake on Oct 16, 2021 11:07:29 GMT -8
Hi all.
I’ve been rearing a group of around 50 Attacus atlas larvae in mostly closed plastic containers with a few air holes. They have been feeding on ligustrum lucidum and doing quite well, except for the fact that almost 40% failed to shed their skins into the second instar. Their head capsules pop off, and that’s pretty much it. They sit in their old skins for a day then die (presumably) due to exhaustion. I understand low moisture can be an issue with this, but they’ve been consistently kept at 80%+ humidity. Does anyone have experience with this happening with other saturniidae?
Thanks in advance.
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Post by Paul K on Oct 16, 2021 15:19:35 GMT -8
Hm, it’s like trying to raise polar bear in Amazon.
My guess is there are many things that can go wrong with native species not to mention Attacus atlas in California.
Wish you good luck
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Post by Crake on Oct 23, 2021 13:54:33 GMT -8
Update: I've got six remaining L3 larvae; the rest succumbed to disease or failed ecdysis. I have the remaining six in individual plastic containers to save some from infection. The room temperature ranges from 66-74*F.
There seems to be a consensus on the forums that Attacus atlas can be an unpredictable species to rear. From what I've been experiencing, here is my advice to others to at least guarantee some survivors:
1. Keep them clean: It's pretty straightforward. Change the food and towels daily. I even rinsed their hostplant (Ligustrum lucidum) and enclosures with hydrogen peroxide as an extra prophylactic measure.
2. Keep them humid (70%+): They desiccate easily at younger instars. Plus, they need humidity to shed their skins, which this species seems to struggle to do. Keeping them in closed plastic Tupperware with a few small air holes should accomplish this.
3. Keep them separated: Probably the most important factor. In a large cohort, the separation of larvae into around a dozen (or more) groups to mitigate infection will almost always guarantee some survivors so long as environmental parameters are suitable.
4. Keep temperatures on the high side: Larvae develop much faster when temperatures are above 75*F. Also, I suspect that the mass failed ecdysis (despite the presence of 90%+ humidity), may have been a result of lethargy induced by cold temperatures.
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Post by exoticimports on Oct 23, 2021 14:34:25 GMT -8
When I raised them I treated them like any other- jammed into an aquarium that was rarely cleaned. Noting that this was through the warm, humid months.
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Post by Crake on Oct 23, 2021 14:41:59 GMT -8
When I raised them I treated them like any other- jammed into an aquarium that was rarely cleaned. Noting that this was through the warm, humid months. That checks out. I guess they really can be unpredictable. |
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Post by Adam Cotton on Oct 23, 2021 22:27:23 GMT -8
I think 75F (24C) is too cold. Tropical insects need to have a body temperature of at least 25C to be active, so 80F is probably ideal.
Attacus atlas larvae are basically solitary in later instars, so keeping them together in large numbers tends to increase potential for disease especially in low air circulation, as in plastic boxes. When I find larvae here I just sleeve them on the host plant in the garden. However, I can understand the problems of trying to rear them in unnatural places. If I understand correctly the air in much of California is very dry, so you would have to find a way to increase humidity while keeping airflow around the larvae as far as possible.
I don't normally rear Saturniids so certainly wouldn't call myself an expert, and have no idea how to rear them in a temperate climate.
Adam.
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Post by Deleted on Oct 24, 2021 7:01:37 GMT -8
I did mine in a temperate US location. I had the advantage of using my discus fish room which had avg temps between 80-85degrees F. I also wrapped my screen cage w plastic, and added still more humidity via misting and a water tray w towel beneath the cage. I fed them wild cherry and only had a few…..I think there were five in a large 3’long x 2’ high x 2’ deep cage just full of cut branches. Interestingly, most came out avg in size with one male being particularly large. My daylight hours (subdued lighting) was for 14-16 hours. I misted during the lighted time with RO water warmed to the same temp as the room and I didn’t overdo it.
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Post by Adam Cotton on Oct 24, 2021 12:47:11 GMT -8
Why did you give them such a long day length? The maximum day length here in June is no more than 14 hours if that, and nearer the Equator it will be less. The minimum day-length here is more than 10 hours in "mid winter".
Attacus atlas is polyphagous. I have found wild larvae on Liquidambar, several species of Annonaceae and even Zanthoxylum here.
Adam.
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Post by Deleted on Oct 24, 2021 14:42:00 GMT -8
Between the ambient diffused light from the morning and sunset times w the aquarium lights, I figured it was abt that much light. It was always a low light as I keep the room on the dark side generally. It was not a timer bright type of lighting. I did it bc that was the normal lighting for that time of year. Now, with mult generational/brooded species like certain Saturniids, I made sure that the fourth in star larvae got a bit more firm light totaling 16 hours so as to have them eclose wo going into diapause. My main effort with atlases was to not over crowd, provide constant warmth, humidity, and fresh food.
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Post by Crake on Oct 28, 2021 8:42:57 GMT -8
Update 2:
I've got four larvae left. Each is inside a small, individual plastic container kept at 82*F+ via a heat lamp. 2 have molted into the fourth instar but are only about an inch in length. Does their growth really skyrocket after the fourth instar? I'm aware this species can have 6 instars, but they're even smaller than Actias luna at L3 despite the abundance of food I've provided.
Other than that, they seem to be doing quite well.
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Post by exoticimports on Oct 28, 2021 9:39:19 GMT -8
That’s awfully small. I didn’t keep records but by fourth instar they should be the size of a Luna.
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Post by Crake on Oct 28, 2021 10:35:46 GMT -8
It was probably the cold. They seem to be doing okay but they're definitely going to be stunted if they make it to adulthood.
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Post by Crake on Nov 15, 2021 14:04:35 GMT -8
Update:
I've managed to get 2 larvae to near-prepupal sizes, the rest died of disease. Hopefully, I'll be fortunate enough to have a male/female pair to continue breeding these amazing moths.
I did notice a very strange shedding phenomenon that occurred between the 3rd and "fourth" instar. The reason I placed quotations around "fourth" is interesting: The larvae had progressed into their chronological 3rd instar (meaning they had shed their skins twice) and were beginning to enter apolysis for the chronological fourth instar. A day later, they had successfully ecdised into their "fourth" instar, and yet for this stage, they were identical to third instar larvae. They were chronologically, fourth instars, but displayed consistent proportions/colourations to the third instar and even exhibited the scarlet blotches on the sides of the A7, A8 abdominal segments. They proceeded to shed into the next stage, which appeared to be the fourth instar but was their chronological fifth. They shed again to their chronological 6th but resembled 5th instars. They are now in their chronological 6th stage, shedding their skins to the chronological seventh instar, but they will probably resemble sixth instars. I know about the supernumerary stages that atlas larvae undergo, but I've never heard of a "seventh" atlas instar, especially one in which there is an apparent discrepancy between the chronology of developmental stages and the physical development of a larva.
I keep thinking I've made some logical errors, but I was meticulous with the records I made. If I did miss something, please correct me.
Any ideas what this is?
Thanks in advance.
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