Perhaps someone has an explanation for this. I collected the caterpillars (photos 1 & 2)from a fleshy Isotoma. A few days later I noted some cocoons (photo 3) in the container, which puzzled me as I had previously hatched parasitic wasps from a similar cocoon. Sure enough, a few more days later and there were four wasps in the container (photos 4 & 5). I checked the Isotoma again and collected two more caterpillars and also two more cocoons (now a total of eight). One of these has now been moving for the past three days and I suspect a wasp will emerge. My puzzle is that I had not seen any wasps around and would find the odds of all of the caterpillars being paratisied, but even if so, why did the larvae form wasp cocoons rather than moth cocoons if they were moth larvae?
The wasps develop inside the caterpillar carefully not killing it until they are ready to form their cocoons, they then break out of the caterpillar and spin their cocoon