ヤリイカ類の繁殖戦略:性淘汰研究の新たなモデルをめざして

摘要

Cephalopods are attractive models for us who are interested in integrative biology involving animal behavior, evolution and reproduction, as they use sophisticated body-color patterning for intra-specific communications and elaborated sperm transfer methods during copulation, which arrows us to estimate their favorable mating systems both at pre- and post-copulatory stages. Especially, squids in the group loliginidae provide rare and ideal opportunities to study pre- and post-copulatory sexual selection and their mutual interactions. Female squids have two distinct sperm storage sites, one at the external body surface and another within the mantle cavity, and these sperm storage sites are tightly linked to alternative male reproductive tactics (ARTs); guarding/consorting and non-guarding/sneaking. The fertilization process that sperm should take after copulation would differ between tactics, which can be a strong selection force driving unequivocal diverged evolution in various aspects of sperm traits. We believe that the squid ARTs can be a suitable model system to uncover some unsolved questions in the area of sexual selection research.