Long-term sperm storage mechanisms in ant queens

Abstract

low metabolic activity of spermatozoa that prevents cellular damage and inhibits reactive oxygen species production. The immotile spermatozoa begin to swim when they are exposed to PBS buffer. This indicates that spermatozoa do not lack flagellum functions and continue to survive even after storage for 5 years. Sperm morphology of ants is similar to that of other hymenopteran species, however differences of the cellular characterization is still unknown (e.g. tolerance to oxida-tive stress) . Highly expressed genes in the ant spermatheca relative to those in body samples have been identified. The genes identified include those encoding antioxidant enzymes, chaperones, and energy metabolism enzymes as well as novel genes that have no similar sequences in the public databases. In future study, it should be necessary to identify the genes responsible for the sperm longevity in ant queens and shed light on molecular and cellular mechanisms of the long-term sperm storage.