Polarized Ovaries of the Long‐tongued Bat, Glossophaga soricina: A Novel Model for Studying Ovarian Development, Folliculogenesis, and Ovulation

Abstract

Glossophaga soricina is a spontaneously ovulating, monovular, polyestrous bat with a simplex uterus, exhibiting true menstruation. Studies conducted on reproductively active, captive-maintained animals established that G. soricina also has polarized ovaries, with the ovarian surface epithelium (OSE) restricted to the medial side of the ovary, and primordial follicles limited to an immediately adjacent zone. Follicles selected for further development are recruited from the medullary side of this zone, and ovulation is restricted to the portion of the ovary covered by the OSE. To further develop G. soricina as a model for studying ovarian development and physiology, ovaries were collected from fetal, neonatal, and adult females and processed for morphological and immunohistochemical analyses. The latter included staining for factor VIII-related antigen (von Willebrand factor) to assess regional differences in ovarian vascularity. The ovarian structure in fetal and neonatal animals was very similar to that in other species that do not have polarized ovaries at comparable stages of development. This indicated that polarization of the ovary does not occur during fetal development, but rather sometime between the neonatal period and adulthood. Vascular elements were abundant in areas of the ovary surrounding early growing follicles, but sparse in the zone of the ovary containing primordial follicles. The polarized nature of the ovaries in G. soricina suggests that this species might be used as a model to investigate the formation, long-term maintenance, and activation of primordial follicles, and the role of the OSE in ovulation and folliculogenesis.

Ovarian morphology and folliculogenesis and ovulation process in the flat‐faced fruit‐eating bat Artibeus planirostris and the Argentine brown bat Eptesicus furinalis: A comparative analysis

“…Ovarian follicles unite (put together) in a specific region of the cortex, characterizing the polarized ovaries, which has been observed in some Phyllostomidae species such as Artibeus jamaicensis (Antonio‐Rubio et al., ), Glossophaga soricina (Komar, Zacharachis‐Jutz, Cretekos, Behringer, & Rasweiler, ), Leptonycteris curasoae (Hood & Smith, ), Phyllostomus discolor , Phyllostomus elongatus (Rasweiler & Badwaik, ) and Sturnira lilium (Antonio‐Rubio et al., ) and some Pteropodidae species, Otopteropus cartilagonodus and Ptenochirus jagori (Heideman, Cummings, & Heaney, ; Heideman & Powell, ; Pow & Martin, , ). Except for G. soricina , in which only the area with the primordial follicles is covered with the ovarian surface epithelium (OSE) (Komar et al., ), A. planirostris , as the other species, presented all the ovary covered by the surface epithelium. In G. soricina , ovulation takes place only in the region of the ovary covered by the OSE, while in A. planirostris and E. furinalis , it takes place at the largest part of the ovarian surface, similar to other phyllostomid species.…”

Morphological variation of the female reproductive organs of the bat Artibeus lituratus during its different reproductive phases

“…However, A. lituratus deviates from this pattern. Similar to the phyllostomid bats Glossophaga soricina (Komar, Zacharachis‐Jutz, Cretekos, Behringer, & Rasweiler IV, ) and Leptonycteris curasoae (Hood & Smith, ), A. lituratus presents polarized ovaries. In these animals, the cortex does not fully coat the medullary tissue and primordial follicles are concentrated only in a specific region of the ovary, generally the portion lined by the surface epithelium and in contact with the infundibulum.…”

Analysis of the reproductive stage and ovarian histomorphometry of Dermanura cinerea (Chiroptera: Phyllostomidae) in an Atlantic Forest fragment of Pernambuco, northeastern Brazil

“…This indicates a possible preparation of the ovarian cortex for maturation of the follicles during the months of high rainfall. Therefore, the events of the annual reproductive cycle of this species may be correlated with an ovarian dynamic through variations without follicular growth (Komar et al 2007).…”

“…However, approaches on the reproductive biology of females are limited and their reproductive pattern are defined based only on investigations of the external morphological characteristics of their body (dilated abdomen, visible nipples with secretion and the absence of hair around it) (Racey 1988, Gannon & Willig 1992, Esbérard 2002. In other countries, there is some recent research on female gonadal histophysiology focusing on folliculogenesis and ovulation of different species of bats located in Colombia (Komar et al 2007), China (Wang et al 2008), Canada (Rintoul & Brigham 2014), Mexico (Antonio-Rubio Porras-Gómez & Moreno-Mendoza 2013) and India (Sastry & Pillai 2013, Singh et al 2015.…”