Caterpillar capers

Four caterpillars devoured an entire shrub last night. I don't know if they were on the plant yesterday, but it  had all its leaves then. Is it possible that they grew to 2-3 inches overnight? They certainly had the food intake necessary for such a growth spurt!
They are a beautiful, almost transparent pale greeny-yellow, coincidentally the colour of the now non-existent leaves, with funny little tails that look as though they have pollen, like the middle of a flower (the name escapes me, but I'm sure you know which bit I mean).

So there they are, exposed to predation by some lucky passing bird, on the twigs of the shrub. I hope one comes along, because I am certainly not touching them and they are, after all, part of the food chain. Perhaps they will pupate, then I will be able to identify the guilty party when the butterflies emerge. I hope so, because I would hate them to transfer to another plant. It will be interesting to see what transpires. I'll come back later in the day to see how they are.

Later in the day...
The last leaf has been eaten and there are now 3. Maybe one escaped. One caterpillar is walking round the edge of the tub, which leads me to think that it hatched on the plant and believes that is the perimeter of its world. (Three hours later, it was still walking round and round and round.) An escapee was making its way across the lawn, heading for the neighbour.

Later...
They've all disappeared. Fate unknown. I think I'll just pop outside with the torch in case they've relocated to the other tubs nearby.