Alternative male mating behaviors dependent on relative body size in captive oval squid Sepioteuthis lessoniana (Cephalopoda, Loliginidae).

We observed the reproductive behavior of the oval squid Sepioteuthis lessoniana in captivity. The male used three different mating behaviors: male-parallel (MP), male-upturned (MU) and sneaking. Male competition over females frequently occurred before and during the female egg-laying period, and the outcome of most fights depended on male body size. Larger males guarded their partners from other males and performed MP mating during the egg-laying period of the paired females. In contrast, there was no pairing and mate guarding in MU mating and sneaking, which were adopted by smaller subordinate males as alternative tactics outside female egg-laying period and during the period, respectively. MP matings were 95% successful, but more than half of MU matings were unsuccessful. Higher mating success in MP mating was achieved through pairing, whereas males in MU mating were less successful because mating attempts without pair formation were often foiled by escape of the female. Sneaking was successful in all cases but occurred less frequently. Spermatophores were attached at the opening of the oviduct in MP mating, whereas they were attached around the female buccal membrane in MU mating and sneaking. Considering the route of egg transportation, higher fertilization success can be expected in MP mating because of the advantageous location of the attached spermatophores. Our results suggest that MP mating is used by larger, paired males during the female egg-laying period, and that MU mating and sneaking are alternative tactics adopted by smaller, subordinate males. These alternative mating behaviors would be conditional strategy dependent on relative body size, because some individual males displayed both MP and MU mating behaviors.

Aortopulmonary fistula due to perforation of the aortic wall of a freestyle stentless valve.

Aortopulmonary fistula occurring as a result of a rupture of the aortic wall of a stentless valve has not been previously reported. A 71-year-old woman suffered aortopulmonary fistula 15 months after replacement of the aortic root with a Freestyle stentless valve (Medtronic, Inc, Minneapolis, MN) and Dacron graft extension to replace the aortic valve and the ascending aorta to the aortic arch. We describe the successful repair of the fistula and simultaneous mitral valve replacement. The cause of deterioration of the aortic wall of the stentless valve, which gradually developed and ruptured, may have been primarily structural injury at the previous operation, with additional insult from the surgical adhesive used.