Morphological Description and Analysis of Octopus rubescens Testis and Sperm

Abstract

Octopus rubescens is a small, yet abundant cephalopod found all along the West Coast. There is little known and relatively few studies done on the morphology of octopus sperm. We acquired a live Octopus rubescens testis and divided it into 4 sections to sample the morphological differences of spermatophore structure. The sections of the testis were stained with DAPI and Tubulin and imaged using immunofluorescence to determine the presence of nuclei and microtubules. The same sections of the testis were also imaged with scanning electron microscopy to compare cellular ultrastructure. We hypothesized that there is a gradient of morphological differences in spermatozoa structure that correspond to the maturity of the sperm. We found that there is a gradient of spermatogenesis with the most immature spermatophores in the wall of the testis and the most mature towards the center of the structure. The length of the sperm tail is very long compared to the size of the head which could be a distinguishing factor for sperm fitness.