title: Morphological structures for potential sperm storage in poeciliid fishes. Does superfetation matter?
abstract: Sperm storage within the female reproductive tract has been reported as a reproductive strategy in several species of vertebrates and invertebrates. However, the morphological structures that allow for sperm to be stored and kept viable for long periods are relatively unknown in osteichthyes. We use histological and stereological tools to identify and quantify sperm storage structures (spermathecae) in 12 species of viviparous Poeciliidae. We found spermathecae in nine species, six of which exhibit superfetation (the ability of females to simultaneously carry within the ovary two or more broods of embryos at different stages of development). These spermathecae are folds of ovarian tissue that close around spermatozoa. We compared the number and size (volume) of spermathecae between species with and without superfetation. Species that exhibit superfetation had a significantly higher number of spermathecae than species that do not exhibit this reproductive strategy. In addition, we found that the mean volume of spermathecae and total volume of spermathecae present in the ovary are marginally higher in species with superfetation. Our results contribute to the understanding of the morphological structures that allow for sperm storage in viviparous osteichthyes and suggest a positive relationship between superfetation and the capacity of females to store sperm.
authors.affiliation: Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria 04510, Ciudad de México, México.
authors.forename: Claudia
authors.initials: C
authors.lastname: Olivera-Tlahuel
authors.affiliation: Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria 04510, Ciudad de México, México.
authors.forename: Maricela
authors.initials: M
authors.lastname: Villagrán-Santa Cruz
authors.affiliation: Departamento de Biología Celular y Fisiología, Instituto de investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria 04510, Ciudad de México, México.
authors.forename: Norma A
authors.initials: NA
authors.lastname: Moreno-Mendoza
authors.affiliation: Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria 04510, Ciudad de México, México.
authors.forename: J Jaime
authors.identifier: 0000-0002-9661-1521
authors.initials: JJ
authors.lastname: Zúñiga-Vega
mesh_terms: D000818:Animals; D003532:Cyprinodontiformes / Q000033:anatomy & histology*; D005260:Female; D016018:Least-Squares Analysis; D008297:Male; D010053:Ovary / Q000166:cytology; D010802:Phylogeny; D011247:Pregnancy; D013045:Species Specificity; D013094:Spermatozoa / Q000166:cytology*; D013476:Superfetation
keywords: Poeciliidae; sperm storage; spermathecae; superfetation; viviparity