Caterpillar on a soapwort plant

Caterpillar on a soapwort plant

Observation - Caterpillar on a soapwort plant. Description: I think this is a caterpillar which I found on the underside of a soapwort plant on my garden balcony. Any ideas which species it belongs to?

I think this is a caterpillar which I found on the underside of a soapwort plant on my garden balcony. Any ideas which species it belongs to?