They're growing
The caterpillars have been busy eating and growing over the last few days. On Saturday, they climbed up to the lid of the jar they call home and started the process of entering pupal stage.
By Sunday, two of them (ones on the right) had turned into cocoons. This morning, all of them have turned into chrysalises and the fifth one is hanging upside down. By the time we get home, they'll all have completed this next step in their life cycle.