The caterpillars are growing and are approximately at their 6th instar stage. Seeing a whole cohort of caterpillars outside its nest during the day like this (see photo below) is unusual, so we had to have a closer look!
The last post featured a parasitic Tachinid fly egg attached on the head of a caterpillar. This time, we found a different fly species laying 1st instar maggots directly on the caterpillar’s body! Some caterpillars were weak/immobile because a fly maggot was growing inside the caterpillar’s body. Once the maggot is ready to pupate, it bursts out of the caterpillar’s body and forms a pupa. After a few days, a fly will emerge from the pupa and the life cycle will restart.