He was very laid back and just popped under the water every few minutes and and would pop back up with some food

and then he was gone
we have moved from France to our new home on the Wild Atlantic Way at Adrigole Bay in the Beara Peninsula South West Cork
It would appear that some of the caterpillars have been attacked by parasitic wasps as they are claiming the apartment wall and eggs emerge and the poor caterpillar covers them with silk and the stays and guards them untill it dies rather than pupate........
We had a few self seeded black radis in the front garden, we left them as the bees loved the flowers and now so it seems so do the large white butterfly caterpillars......like the leaves.