Rearing notes for our cecropia moth (Hyalophora cecropia) cocoons. Stock originated as eggs from New York, June 2016; currently in the F1 generation.​

Late this evening, we found this whopping male cecropia (Hyalophora cecropia) in our pupae box. Granted, it is actually quite small, even for a male, but having not seen anything close to its size in so long it still comes off as being huge. What is interesting is that it is extremely pale for a male (which are generally darker than females); the black is sort of a dirty gray and the red is is rather mellow. This is unlike the phenotype we observed in the previous generation or what is typical. It may have something to do with the different rearing conditions that the current brood experienced, or it could simply be odd genetics.  

This male took 21 days to eclose, which is reasonably long for a moth of this size. Still, this is down quite a bit from the times that we observed in last year, where the moths took about two months to come out. Most likely, the pupae broke diapause immediately this time around because the juxtaposition of cold and warm was dramatic enough when they were taken out of the refrigerator; our dorm is set at about 70 °F 24/7. Last year when we took them out of the refrigerator, it was still February where it was only about mid 50-60s °F at room temperature. 

Anyway, hopefully, this timing is right. Now that it is mid-May with the weather warm, we are certain that the wild population should be stirring by now. Granted, cecropias are generally the latest of the saturniids, owing to their larger size (longer development time) and may not be in full flight until well into June. Nonetheless, if a female does comes out later, we will try to call in a wild male to avoid having to inbreed for a second time in a row. 

Since the weather has started to show signs of warming starting last Monday (not linearly but, on average, slowly but surely increasing) we had most of our pupae that were being kept refrigerated at our home in Albany, California sent to us which we received today. The pupae are, for the most part, in good condition. One Papilio eurymedon and one or two Smerinthus opthalmica dried out, several Manduca sexta seem to be rotting (may be disease as many of the last instar larvae of this brood died from disease), and a few lunas (Actias luna) are evidently dead (brood generally undersized and unhealthy). Surprisingly, all of the regals (Citheronia regalis) are alive. We can't quite tell with the cecropia (Hyalophora cecropia) at the moment since their cocoons are thick, but they seem more or less okay. ​All of the eastern festoons (Allancastria cerisyi) are alive. We did not have sent the rutulus (P. rutulus) for fear that they might eclose too early or in shipment, anise (P. zelicaon) because the umbels (Apiaceae) here have not grown out yet, or pipevines (Battus philenor hirsuta) because there is no pipevine (Aristolochia) here. 

The trees are just starting to leaf out, so the hope is that by the time that we eventually might obtain eggs from the pupae that we did receive, all of the food plants will be ready to use. For the native species, such as the cecropia and luna, we are also hoping that by taking them out of cold storage around the same time that the local weather is warming should help ensure that they eclose in sync with the local populations for the purpose of outbreeding with wild males. ​

Brian Liang
Brian Liang is a student at Cornell University in Ithaca, New York pursuing an undergraduate degree in entomology. He is co-owner and a main contributor of the Liang Insects blog, insects articles, and site design. ​

Ideally, we probably should have done it immediately when we returned to Albany California in mid-December or perhaps even ask our mother to do it for us even earlier, but as of today we have begun refrigerating (40°F/4-5°​C) our pupae that require it. 

These include: all of the Saturniidae--cecropia (Hyalophora cecropia), luna (Actias luna), and regal (Citheronia regalis); Manduca sexta; and, we are assuming, the pale swallowtails (Papilio eurymedon), which come from Utah/Oregon, and eastern festoon (Allancastria cerisyi). Although our Smerinthus opthalmica pupae are native stock that do not require cold treatment, we also decided to toss twenty of so of these in as well as a risk splitting measure because it is difficult to predict what the situation will be when the ones outside the refrigerator emerge. Ideally, we would have put all of the opthalmica pupae in the refrigerator as well as the diapausing pupae of the other species we have such as the western tigers (Papilio rutulus​) and anise (Papilio zelicaon) swallowtails but because all of these are native, it could potentially be harmful in the long run. 

A lot of strange things have happened with our cecropia moth (Hyalophora cecropia) larvae since we left to Ithaca, New York in August. It is already strange enough that they took such a long time to complete their development, which can probably be attributed to bad rearing conditions outside as well as inbreeding, but another thing that we have never figured out is how so many of them disappeared from their sleeves over time. Of course, a number of them fell to disease or were attacked by European paper wasps (Polistes dominula) that were able to bite through the netting, but where the rest of them went has always been a mystery considering that we started off with several hundred and ended now with less than twenty.

We can only assume that a significant number of them must have found a way to escape the sleeves, despite them seemingly being clipped completely shut. Our mother did find a cocoon on our apple tree outside a sleeve while we were in Ithaca and another one when we first came back home to Albany, California. We ourselves spotted another one a few days ago on the tree that is now completely bare. 

Although the cocoons are drastically smaller than the ones that we reared last year and are far smaller than what they should ideally be, they seem healthy for the most part with the exception of two that we ended up throwing out because of low weight. 

Back in Albany, the last of our cecropia moth (Hyalophora cecropia) larvae are finishing their cocoons. Stock originated as eggs from New York, June 2016.

It is mind-boggling to us that the first species to hatch this year is the last to finish. Our cecropia moth (Hyalophora cecropia) cocoons reared from last year first started eclosing near the end of April and we already had a thousand eggs by May. . . and yet five months later the last of them are still finishing up. Our mother sent us these two pictures today, first of two cocoons she recently collected from the apple (Malus sp.) tree sleeves and the second of a runaway larva that she found back that is only now spinning. 

We blame this slow growth on the horrible conditions that the larva had to endure in our California Bay Area weather as well as overcrowding. It was simply not a good idea to start the larva off immediately in sleeves where they get easily lost and killed by the cold, windy, and dry climate. The ones that did survive were simply not healthy either, growing at this sluggish rate and not attaining a very large size at all (a very steep drop from last year's average). At the same time, every last one that we attempted to rear inside were wiped out by disease, which is typical for this species. With that said, one of the things that we greatly look forward to here in Ithaca is rearing the eastern species in their proper climate.