As I’ve mentioned, one of my sub-hobbies under the grand heading of Lepidoptera is rearing caterpillars. My latest ‘big’ rearing project is the Buff Ermine moth: the 16th species whose life cycle I’ve observed (well, technically 15th seeing as the Knotgrass caterpillar I captured last year was actually dead – and then again technically 14th since I mistook some sawfly larvae for moth caterpillars… but anyway.) I’ve finally got round to writing this, a month after it all started.

I was out weeding in the garden on 9 August when I found two little 15mm aterpillars: one hairy, and the other green and bald – so that’s what I named them: Hairy and Green. Guess which one is in this photo!

09Aug11 Buff Ermine caterpillar

Green, as it turned out, was bald becuase had shed his hair in preparation for moulting his skin, which he did two days later. Hairy followed suit (without shedding much hair) three days later – in fact he would do everything about three or four days after Green did it.

They went through two moults to get to their final instar – here Green has just emerged from his old skin to reach this stage. As you can see, his hair came out with a sheen that would put Pantene Pro-V TV ad models to shame, but he soon gave a little twist to puff the hair out, assuming the classic furry-caterpillar-style.

18Aug11 Buff Ermine caterpillar... feeling nourished after final moult

I kept them in separate containers – Green in a transparent one, Hairy in an opaque one, and they grew noticeably accustomed to the light levels: when I brought them outside into bright sunshine, Hairy would retreat under a leaf while Green would carry on regardless.

24Aug11 Buff Ermine caterpillars (last instar)

When Green lost interest in dandelion leaves and started running around his container I transferred both caterpillars to a pupation house (my fancy name for a peanut butter jar with a stick in it) and put it outside in a shady spot a few days later. After spinning a really bad excuse for a cocoon, Green pupated 1 Sep (below). Hairy did less running around, made a slightly better job of his cocoon, and pupated today, 5 Sep.

03Sep11 Buff Ermine pupa

They’ll stay as pupae over the winter, and emerge… some time next year. I am very much looking forward. As I am looking forward to seeing the 3 Large Whites, 5 Noctuids, 5 micros and 6 Geometrids of two different species, all of which have taken up residence of their own volition in my back yard, and some of which have pupated already. And I’ll try and post some photos of them… soon. Which, like the Biblical ‘eternal’, is an indefinite period of time.

Species study 16, project A: Buff Ermine (Spilosoma luteum)