Morphological analysis of the male reproductive accessory glands of the bat Artibeus lituratus (Phyllostomidae: Chiroptera)

Abstract

Bats are distributed worldwide from tropical to temperate regions. Despite their wide geographical radiation and advances in studies using evolutionary approaches, aspects related to the reproduction of these animals remain poorly explored, especially those related to the male reproductive accessory glands (RAGs). Thus, the aim of this study was to analyze the morphophysiology of the male RAGs in the bat Artibeus lituratus. The RAGs in A. lituratus are composed of a compact intra-abdominal glandular complex, consisting of the prostate with two prostatic regions (ventral and dorsal), plus Littre glands and a pair of extra-abdominal bulbourethral glands. The ventral region of the prostate has an epithelium with variable morphology, due to its holocrine type of secretion. In contrast, the dorsal region has a typical cubic-to-columnar pseudostratified epithelium. Both regions contain two cell types, basal and secretory cells. Similar to the epithelial morphology, the secretion also varies, with the ventral region containing numerous PAS-positive globular vesicles, whereas the dorsal region has a more fluid, hyaline and PAS-negative secretion. Littre glands are dispersed in the connective tissue of the urethra, while the bulbourethral glands are located in the penile root, both glands with cubic-to-columnar pseudostratified epithelium and globular PAS-positive secretion. The results demonstrate that the RAGs of A. lituratus are composed of two prostatic regions, ventral and dorsal, and urethral and bulbourethral glands, with no seminal vesicles. Each prostatic region has unique and distinctive characteristics, with the ventral region presenting an exclusive holocrine nature and the dorsal region having similarities to the ventral prostate of rodents.

Light and Electron Microscopic Studies of the Seminal Vesicular Glands of the African Straw-coloured Fruit Bat, Eidolon helvum

“…The paired seminal vesicular glands of Eidolon helvum appeared as large milky coloured and somewhat spiral shaped tubes located dorsolateral to the urinary bladder and prostate gland ( Figs 1A and B). The seminal vesicular tubes appeared tapered at their openings into the urethra but enlarged as the tubes coiled centripetally outwards indicating availability of seminal vesicular glands unlike most bats that lacked this gland (Christante et al, 2015;Martins et al, 2015;Beguelini et al, 2016;Santos et al, 2018). The spiral shape in Eidolon helvum confirmed the variability in bats (Krutzsch and Nellis, 2006;Fard and Ghassemi, 2017) and other mammals (Badia et al, 2006;Samuelson, 2007;Adebayo et al, 2014;Nissar et al, 2014;Akbari et al, 2018) with seminal vesicular glands.…”

“…The seminal vesicular glands with other accessory reproductive glands produce and elaborate numerous secretions important in male reproductive functions. The secretions from the seminal vesicular glands are rich in prostaglandins, proteins, amino acids and fructose necessary for the motility, viability and survival of the spermatozoa (Stevens and Lowe, 2001;Rochel et al, 2007;Santos et al, 2018). The secretions also contribute to vaginal plug formation in some rodents (Chaves et al, 2011).…”

“…The glands are saccular in human, horses and rats, compact and multi-lobulated in pigs, bulls and hedgehogs and are branched and tubular in rodents (Samuelson, 2007;Adebayo et al, 2014;Akbari et al, 2018). In the bat species which showed great diversity in the male reproductive structures influenced greatly by latitude, abiotic factors and food availability (Puga et al, 2013), the seminal vesicular glands shows great variations in shape and availability, being present in some bat species (Krutzsch, 2005;Fard and Ghassemi, 2017) but absent in others (Pal, 1983;Krishna and Singh, 1997;Christante et al, 2015;Martins et al, 2015;Beguelini et al, 2016;Santos et al, 2018).…”

Three-Dimensional and Histological Observations on Male Genital Organs of Greater Horseshoe Bat, Rhinolophus ferrumequinum

“…The mammalian male reproductive organs comprise paired testes, epididymis, and accessory genital glands, with the testis, epididymis, and accessory genital glands exhibiting variation in shape and position (Miotti et al 2018;Santos et al 2018). Four types of testes locations (permanently abdominal, permanently scrotal, migratory, and external) are described, which do not necessarily reflect phylogenetic relationships (Table 1).…”

Seasonal variations in the morphology of the seminal vesicles of the African straw‐coloured fruit bat (Eidolon helvum)

“…The seminal vesicles, prostate, ampullary and bulbourethral glands constitute the accessory reproductive glands (ARGs) of mammalian males. The ARGs produce and elaborate numerous secretions in the ejaculate, which are necessary for the motility, viability and survival of the spermatozoa within both the male and female reproductive tracts (Dyce et al., 2010; Puga et al., 2013; Rochel et al., 2007; Santos et al., 2017; Stevens & Lowe, 2001). The seminal vesicles vary greatly in occurrence and morphology, even among closely related bat species (Krishna & Bhatnagar, 2011).…”