This photo demonstrates the mating behaviour of marine polyclads which can be described as an act of hypodermic insemination. During copulation, worms were observed to move towards each other, touch, then roll around together (= "rearing up"), simultaneously everting their penis papillae and stylets outward. They then try to stab each other anywhere (= "penis fencing"). When one animal is successful in penetrating the other, as shown on this photo, it holds on with its stylet embedded in the epidermis of its partner and spermatozoa are transferred (whitish patches of worm in front).
Picture details
Genus Pseudoceros
Species bifurcus
Family Pseudocerotidae
Order Polycladida
PHOTO © Copyright Leslie Newman, School of Resource Science and Management, Southern Cross University, PO Box 157, Lismore, NSW, Australia 2480
Comments: Check out the introductory page to learn more about the mating behaviour of marine polyclads!