Calleta Caterpillar Ecdyses into Fifth Instar

Our first Calleta caterpillar (Eupackardia calleta) has ecdysed into fifth instar.

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After 2 days in apolysis, our first Calleta caterpillar ecdysed into fifth instar. Previously, each instar looked very similar, with a bright yellow body, stubby, uniformly sized tubercles, and black spots, but the fifth instar finally becomes a little different. The most obvious difference are the tubercles. They are now a bright, sky blue and are much larger and knob-like, resembling the thoracic tubercles of Hyalophora cecropia. The base of the tubercles has a dark yellow ring. The turquoise triangle on the head capsule is also more prominent due to the larger head capsule size. ​The rows of black spots down the body have been significantly reduced, giving the body a much yellower color. The prolegs are even hairier than they were in fourth instar. Overall, the fifth instar is the brightest and most colorful instar, possibly even aposematic. 

The caterpillar weighs 1.3g which is quite small compared to other newly ecdysed fifth instar Saturniidae, though we probably haven't reared it very well since the host plant and weather aren't ideal and this is our first time with the species. It also took 13 days in fourth instar (10/8-10/21) which is quite a long time. In fact, growth rate for this species has been quite slow since the beginning, as the oldest individual spent nine days in third instar from 9/29-10/8, five days in second instar from 9/24-9/29, and seven days in first instar from 9/17-9/24.

- Alan