I posted about the Operation a few posts earlier and went back to check on the caterpillars. Some have disappeared, just as I feared, possibly due to the heavy splashing rain on the remaining leaves of the Calotropis gigantea (common name: Crown Flower) in recent days.
The good news is the remaining caterpillars have grown bigger on the few leaves and I found a jade-coloured pupa. Nature builds it to be so unique and it is hard to imagine how a pupa like this can emerge as the orange colour Plain Tiger butterfly.