Ultrastructural characteristics of the spermatogenesis during the four phases of the annual reproductive cycle of the black myotis bat, Myotis nigricans (Chiroptera: Vespertilionidae). Issue 10 (16th July 2013)

• Record Type: Journal Article
• Authors: Beguelini, Mateus R.; Taboga, Sebastião R.; Morielle‐Versute, Eliana
• Is Part Of: Microscopy research and technique. Volume 76:Issue 10(2013:Oct.)
• Page Start: 1035
• Page End: 1049
• Publication Date: 2013-07-16
• Subjects: Electron microscopy -- Technique -- Periodicals; Microscopy -- Periodicals; Microscopy -- Technique -- Periodicals; 502.825
• DOI: 10.1002/jemt.22264
• Languages: English
• ISSNs: 1059-910X

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p> <italic>Myotis nigricans</italic> is an endemic species of vespertilionid bat, from the Neotropical region, that resembles temperate zone bats in their reproductive cycle; presenting an annual reproductive cycle with two periods of testicular regression, which are not linked to the apoptotic process and seems to be not directly linked to any seasonal abiotic variation. Thus, this study aimed to ultrastructurally evaluate their reproductive cycle. The process of testicular regression could be divided into four periods: active; regressing; regressed and recrudescence; with all presenting distinct characteristics. The active period was similar to that of other bats, presenting the complete occurrence of spermatogenesis, with three main types of spermatogonia (A<sub>d</sub>, A<sub>p</sub>, and B) and 12 steps in spermatid differentiation; however, it differed in having the outer dense fibers 1, 5, 6, and 9 larger than the others. These three types of spermatogonia undergo considerable morphologic changes from regressing to the regressed period, and in the recrudescence, they return to the basic morphology, which reactivates spermatogenesis. In conclusion, our study described the process of spermatogenesis, the ultrastructure of the spermatozoa and the distinct morphologic variations in the ultrastructure of the testicular cells of <italic>M. nigricans</italic> during the four different periods of its annual reproductive cycle. <italic>Microsc. Res. Tech., 76:1035–1049, 2013</italic>. © 2013 Wiley Periodicals, Inc.</p> </abstract>