Notes on Larvae Rearing in Captivity:
As I had not been able to photograph a Goat Moth in the wild, when I saw that Devon Butterflies were advertising larvae for sale in September 2016, I decided to order some and attempt to rear them. In the wild, Goat Moth larvae can take 3 - 4 years to reach full size, but in captivity this can be reduced considerably to 1 year, and is just about possible in 6 months. This was my goal, as we were due to go on holiday at the end of March 2017 and I needed the larvae to pupate before we left.
They arrived promptly, but were being fed on apple. I had read that swede was readily accepted by the larvae and, being denser, lasted longer, so I immediately transferred them and they soon burrowed into the swede.
For a while, frass was being produced by all of them, but gradually some tunnels appeared to become inactive. After a fortnight of no frass production from all but one tunnel, I transferred the one active larva to a fresh piece of swede and discarded the rest.
It was difficult to monitor the health and growth of the larva, as I only saw it when I moved it to fresh food. This was a tricky process, since using a knife to cut the piece of swede was too risky as it was impossible to know where the tiny larva was, so I had to tear the swede apart until I could find it.
After 55 days, the larva moulted to L2. Until then, I had kept it in an unheated room, and in order to try and speed up growth, I moved the container into a much warmer room. However, although the container had holes in the lid, it was small, ventilation was poor, and the swede developed moulds and softened rapidly in the warm environment. As this may have been harmful to the larva, I transferred it to a small vivarium where there was much better air circulation and, although the small piece of swede became somewhat leathery, it did not rot so quickly.
As swede frass seemed to be much wetter than wood frass and may have caused clogging, I cleared the tunnel daily as much as possible to aid ventilation and drainage. It occurred to me much later that lack of air circulation and/or accumulation of liquid may have been why I lost most of the L1 larvae (the survivor had chosen a very small, rather dry, remnant of swede and frass was more readily pushed clear).
You are maybe thinking at this point that I was fussing unnecessarily but, having only the one larva, I wanted to give it the best chance of survival that I could.