Nudibranch predation

This week Mood – one of our repeater guests that has been here at NAD Lembeh many times – found this yellow Nudibranch at Nudifalls: a Bristly Jorunna (jorunna pavra). He had never seen this particular Nudi before, so he stayed there for a while. Eventually he recognized a little white “Blob” at the gills of the Nudibranch and wondered what this could be. As the yellow nudi was already quite small, it was not easy to determine with the eye. As so often in Lembeh a photograph and a look on the LCD screen helped a lot …
That “Blob” actually turned out to be a Nudibranch as well – a predator Nudibranch: a juvenile orange spotted Gymnodoris. And as a predator, it was feeding on the gills of the jorunna. Several species of Gymnodoris can be seen here in Lembeh Strait, with this kind of orange spotted Gymnodoris arguably beeing the most common one. All Gymnodoris  feed on other dorid nudibranchs … usually they follow their trails and then catch them. Juveniles are either catching small dorids or – like seen here in the picture – feeding on the gills of bigger nudibranchs.