Male reproductive system of spiders

Abstract

The male reproductive system of spiders is very diverse across taxa regarding its gross morphology and sperm ultrastructure. The primary male genital system, which consists of testis, deferent duct and ejaculatory duct, varies remarkably across taxa. Spermatogenesis occurs usually throughout male adulthood, but can be ceased and terminated with the final molt (permanent sperm depletion). The ultrastructure of spermatozoa is complex and reveals high phylogenetic potential. Nevertheless, the evolution and function of the sperm cell components and sperm conjugates is not yet well understood and should be addressed in the future with new methods including computer-based 3D reconstruction based on transmission electron microscopy sections. This will not only help to understand the organization of the often complex spermatozoa but also increase the reproducibility across taxa. The same is true for the recently revealed high structural diversity of seminal secretions. The influence of sex-related secretions was never studied but is indispensable to understand spider reproduction.