Albany, California Updates (9/18/17): Samia ricini Egg Hatchlings; Actias luna Update; Manduca sexta Larva; Papilio zelicaon Pupae

Back in Albany, our eri silkmoth (Samia ricini) eggs have begun to hatch, luna moth (Actias luna) eggs have proven infertile, Carolina sphinx moth (Manduca sexta) rearing continues, and anise swallowtail (Papilio zelicaon) rearing finishes. 

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It's been a while since we have received updates from our mother about the ongoing rearing projects, but today she sent us pictures of several of the species.

The ricini's have finally begun to hatch, just short of two weeks since they were laid which is quite fast compared to previous rearings. This is probably because of the intense heat Albany is experiencing these days, with the temperatures hitting record high 80's and 90's °F at some point around the time during and after these were laid. Bear in mind that even 80 °F is a rare occurrence any time of year there. 

As for the Manduca's, our tells us that there aren't as many left as she had hoped there would be. She only ever obtained one pairing and got about 70 eggs out of that and there are apparently much less than that now. Based on last time's rearing when we did it ourselves, this species can be troublesome in the first two instars because they are so small (proportional to how big the full grown larvae and the moths are) and thin-skinned such that accidental deaths and desiccation is common. It is hard to see in the picture, but I would say that they are mostly third and fourth instars in there already. Again, this is surprisingly fast considering that the eggs were laid on September 2, even for this species, and probably has to do with the extreme heat. 

The luna (Actias luna) eggs were also laid on the 2nd and still have not hatched. When she told us this, we suspected that they may be infertile and these new photos confirm that. None of us know what exactly went wrong given that we know for a fact that at least one pairing occurred. These moths were second generation inbred (perhaps more if they were inbred before we received the original eggs), so that might have something to do with it? It seems somewhat doubtful though, but we really don't have any other explanations right now.

Finally, we have the zelicaon. It has been a long and messy ride with these with us making massive hand-pairings right and leaving a small plant in our front yard clobbered in hundreds of eggs right before we left. A good chunk of these eggs and resulting larva were clearly lost or killed somehow in the process (which is somewhat to be expected when rearing in bulk in an outdoor cage that doesn't provide complete protection from enemies) as she informed us a while ago that she only counted 80 or so larva of different sizes. Along the way, she also found a few wild larva and eggs scattered around our fennel (Foeniculum vulgare) plants, which makes the rearing even messier. At some point, we told her to take all the larva inside to try to minimize losses (especially when they are ready to pupate) and to try to get them to diapause with darkness. After all of this, it was a big relief when she told us that most of them had pupated and sent us this picture showing that a good enough amount of them had made it and that almost all of them were light tan (diapausing). When we asked her what she did to get them to diapause, she told us that she reared the larva in opaque tubs but put that she did it completely outside, opening the lids in the morning (around 8-9 AM) but making sure to put them in a shaded location as not to let them burn out from the sun. From this, we can only assume that the natural conditions of this time of year are probably enough to cue most larva into diapausing which is why this worked. 

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Authors
Brian Liang

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