Reproduction
Polyclads are hermaphrodites and reproduce by internal fertilization.
They have two male pores and one female pore (Figure 1).
Insemination can take place on any part of the surface of the flatworm. They have pseudotentacles to gather chemosensory information to find a mating parnter. Once a mating partner is found, the two hermaphrodites undergo “ penis fencing”. They attempt to stab each other using a pronged penis stylet to inject sperm into the body wall of the other (Newman et al., 2003; Michelis, 2006).
Figure 1. Ventral view with male and female pores labelled
Figure 2. Two P. bedfordi flatworms encounter one another and
start engaging in penis fencing.
Video 1. Mating via penis fencing strategy of 2 P. bedfordi flatworms |