Within-female sperm allocation in Enoploteuthis chunii is associated with polyandry and male-biased sex ratio.

Abstract

One of the unusual reproductive features in cephalopods is the flexibility of sperm deposition sites in females. Recently we reported that female Enoploteuthis chunii possess not only a major sperm receptacle (MSR) but also a cryptic sperm pocket (CSP) and CSP utilization increases towards the end of the reproductive season. This may occur due to male-male competition over insemination sites, as a male-biased sex ratio and CSP utilization are tightly correlated. The microsatellite-based genotyping revealed that both MSR and CSP are used by the same males, a similar phenomenon previously found in Loliolus sumatrensis , which is herein hypothesized to be a strategy associated with sperm allocation.