Ultrastructural characteristics of spermatogenesis in Pallas's mastiff bat, Molossus molossus (Chiroptera: Molossidae)

Abstract

Despite the large number of species, their wide distribution, and unique reproductive characteristics, Neotropical bats have been poorly studied, and important aspects of the reproduction of these animals have not been elucidated. We made an ultrastructural analysis of spermatogenesis in Molossus molossus (Molossidae). The process of spermatogonial differentiation is similar to that found in other bats and is also relatively similar to that of Primates, with three main spermatogonia types: A(d), A(p), and B. Meiotic divisions proceed similarly to those of most mammals, and spermiogenesis is clearly divided into 12 steps, in the middle of the range known for bats (9-16 steps). Formation of the acrosome is similar to that known from other mammals; however, the ultrastructure of spermatozoa was found to have unique characteristics, including many wavy acrosomal projections on its surface, which seems to be specific for the family Molossidae. Comparing the ultrastructure of the spermatozoon of M. molossus with other bats already study, we observed that three characters vary: morphology of the outer dense fibers, of the perforatorium, and of the spermatozoon head. The great similarity of morphological characters between M. molossus and Platyrrhinus lineatus suggests that M. molossus is more closely related to the Phyllostomidae than to the Rhinolophidae and the Vespertilionidae.

Stages and duration of the seminiferous epithelium cycle in the bat Sturnira lilium

“…The cytoskeletal organization of S. lilium is typical of the cytoplasm of elongated spermatids, and the characteristics of the spermatids were similar to those described in other species of bats (Beguelini et al. , ).…”

“…The early stages of the formation of the flagellum were also apparent in the region that will originate the sperm tail. The cytoskeletal organization of S. lilium is typical of the cytoplasm of elongated spermatids, and the characteristics of the spermatids were similar to those described in other species of bats (Beguelini et al 2011(Beguelini et al , 2012.…”

Male reproductive cycle of hibernating Korean greater horseshoe bat,Rhinolophus ferrumequinum korai(Chiroptera: Rhinolophidae): annual cycle of the seminiferous epithelium and morphological changes of the testes

“…The maximum activity of spermatogenesis is known to be related to the diameter of the largest seminiferous tubules and the maximum testicle weight (Racey 1974;Racey & Tarn 1974;Gustafson 1976). Sperm production is directly related to the size of testes (Amann 1970;França & Russell 1998;Bedford 2008). Although body temperature does not inhibit sperm maturation in epididymis fluid, it has a significant effect on sperm viability and sperm maturation in storage capacity and cauda epididymis (Bedford 2008).…”

Structure, histochemistry and seasonal variations of the male reproductive accessory glands in the Pallas’s mastiff bat, Molossus molossus (Chiroptera: Molossidae)

“…It is the most common bat in the urban areas of Brazil. It is known to be polyestric with two annual reproductive breeding seasons in Brazil, one in March-April and another in November, and sexually active males are found almost year round (Fabián and Marques 1989;Beguelini et al 2010Beguelini et al , 20122013a;Morais et al 2012Morais et al , 2013. However, information about the reproductive process in males is still scarce.…”