It was an uneventful dive until I hit a sandy flat area at about 45 ft. off the island of Santo in the Vanuatu group. What appeared to be a turnip patch in the distance turned out to a gathering of Chelidornura varians exhibiting mating behavior. The individual "turnips" were in fact inverted C. varians with their head shields encased in an egg mass. How odd was my first impression upon settling down in the sand to watch the spectacle unfolding before me. In particular three C. varians were selected to observe. Two were in the inverted posture and the third was circling around interacting with the other two "turnips." By this I mean it would climb the inverted C. varians to the tail, go back down to the sand, head out into the sand about 6 to 8 inches but always return to repeat this strange behavior. After observing this for about ten minutes, the video light was turned on the the action recorded on video (Quick Time File). You can observe for yourself.
As it turns out this behavior is mentioned both on Bill Rudman's Sea Slug Fourm and also on page 121 of Dave Behren's Book, Nudibranch Behavior.
Our little sea slug friends continue to amaze me. At times you may think you've seen it all but you can bet mother nature has many more unplayed hands in her card deck of secrets!
Ali Hermosillo and Dave Behrens
Pacific Coast Nudibranchs and Nudibranch Behavior
Send Dave mail at firstname.lastname@example.org