The marked dextro-dominance causes accentuated morphophysiological variations in the female reproductive organs of the bat Molossus molossus.

Molossus molossus is an insectivorous molossid bat that is important in the control of nocturnal insects. It is the nominal and the most representative species of the family. However, there are few studies about its reproduction. Thus, this study aimed to evaluate variations of its female reproductive organs during the different reproductive phases. Twenty adult females, divided into four sample groups (non-reproductive, early and advanced pregnancy and lactation), were submitted to morphological and morphometric analyses. Results show that the female reproductive system of M. molossus is composed of ovaries, a short bicornuate uterus, slightly convoluted uterine tubes and vagina. The system presents a distinct morphofunctional asymmetry, with a marked dextro-dominance. The right ovaries of all analyzed groups (NON, P1, P2, and LAC) showed follicles at different stages of development, a large number of interstitial glands and a small, but persistent corpus luteum. Ovulation is simple, unilateral and preferential, occurring exclusively in the right ovary. Follicular development in the left ovary usually does not pass the secondary stage. Implantation is fundic and preferential, occurring exclusively in the right uterine horn. The placenta is formed with two distinct chorioallantoic portions, one diffuse endotheliochorial, which covers the entire uterine cavity and regresses in the final stages of pregnancy, and the principal discoidal hemochorial portion, formed in the implantation site. The uterine cervix presents a pseudostratified epithelium, while the vagina has a little keratinized stratified epithelium, which does not accentually vary in the different reproductive stages, but can disrupt and shed in some cases.

Annual reproductive cycle of males of the great fruit-eating bat, Artibeus lituratus: Testicular variations, abiotic regulation and sperm analysis.

Artibeus lituratus is one of the most well-known bat species in the Neotropics, probably due to its high abundance and the ability to inhabit urban areas. It plays an important ecological role in the ecosystem due to its ability to disperse seeds, which contributes to the regeneration of degraded areas. Actually, the species has been used as an important experimental model for ecotoxicological studies of the impact of pesticides on male reproduction. Despite that, the reproductive pattern of A. lituratus is still controversial due to inconsistent descriptions of the reproductive cycle. Thus, the aim of the present work was to evaluate the annual variations of the testicular parameters and sperm quality of A. lituratus and analyze their responses to annual variations in abiotic factors in the Cerrado area in Brazil. Testes of five specimens were collected each month for one year (12 sample groups) and submitted to histological, morphometric, and immunohistochemical analyses. Analyses of the sperm quality were also performed. Results demonstrate that A. lituratus presents a continuously active process of spermatogenesis throughout the year, with two significant peaks in spermatogenic production (September-October and March), which indicates a bimodal polyestric pattern of reproduction. These reproductive peaks seem to be related to an increase in proliferation and, consequently, in the number of spermatogonia. Conversely, seasonal variations in testicular parameters are correlated with annual fluctuations in rainfall and photoperiod but not with temperature. In general, the species presents smaller spermatogenic indexes with a similar sperm quantity and quality to other bat species.

Morphophysiology of the male reproductive accessory glands of the bat Pteronotus gymnonotus (Mormoopidae: Chiroptera).

Mormoopidae is an exclusive Neotropical family of bats, distributed from southern Mexico to northeastern Brazil. Possibly due to its endemic distribution and very low occurrence (rarity), descriptions of their reproductive accessory glands (RAGs) are still lacking. Thus, this study aims to characterize the male RAGs of Pteronotus gymnonotus (Mormoopidae: Chiroptera). Results demonstrate that the RAGs of P. gymnonotus is composed of a prostatic complex, comprising two regions (ventral and dorsal prostates); urethral (Littre) glands, a pair of bulbourethral and ampullary glands, with the absence of seminal vesicles. The ventral prostate has an atypical epithelium, due to its holocrine secretion; which contains numerous PAS-positive globular vesicles. The dorsal prostate has a cubic-to-columnar pseudostratified epithelium, containing fluid PAS-negative secretion. The ampullary glands present cubic-to-columnar pseudostratified epithelium, with secretion varying from granular and PAS-negative to fluid and PAS-positive. Urethral glands are dispersed in the submucosa of the urethra, while the bulbourethral glands are located in the penile root. Both glands have cubic-to-columnar pseudostratified epithelium with PAS-positive globular secretion. In conclusion, we propose that the RAGs of P. gymnonotus possibly evolved from a common emballonurid ancestor, shared with the families Phyllostomidae and Noctilionidae, but with the development of an exclusive apomorphy, the ampullary glands.

Comparative analysis of male reproductive accessory glands in bats Histiotus velatus (Vespertilionidae), Molossus rufus (Molossidae), and Peropteryx leucoptera (Emballonuridae).

Despite the high number of species and wide geographic dispersion, reproductive accessory glands (RAGs) of bats have traditionally received little attention in the literature, with some species not even having a basic description of their composition and structure. Thus, this study aimed to analyze and compare the composition, anatomy, and histology of male RAGs of bat species belonging to three of the largest (cosmopolitan) bat families: Vespertilionidae (Histiotus velatus), Molossidae (Molossus rufus), and Emballonuridae (Peropteryx leucoptera), in order to understand the variations in the bat RAGs. The results showed that the RAGs of H. velatus, M. rufus, and P. leucoptera are composed of an intra-abdominal prostatic complex, associated with the urethra, urethral glands, and a pair of inguinal bulbourethral glands; without ampullary glands or seminal vesicles. The prostatic complex can be composed of two (M. rufus and P. leucoptera) or three (H. velatus) prostatic regions, and can be compact (P. leucoptera), semi-lobed (M. rufus), or multilobed (H. velatus). Each prostatic region has unique and distinct characteristics, with the ventral region presenting a holocrine nature, exclusive to bats; while the dorsal and/or dorsolateral regions have similar characteristics to the ventral prostate of rats and to the human peripheral zone.

The prostate of the bat Artibeus lituratus: Seasonal variations, abiotic regulation, and hormonal control.

The prostate is an important gland that contributes to the male reproductive process, producing secretions that are essential for maintaining ideal conditions for the survival of sperm. Studies indicate a wide variation in the occurrence, morphology, and physiology of this gland in mammals, especially in bats, with this variation being related not only to the number of regions and their degree of compaction/lobulation but also to fluctuations in their functioning throughout the year. Thus, the aim of this study was to evaluate the annual morphological and physiological variations of the male prostate of Artibeus lituratus and analyze their responses to annual abiotic variations and hormonal control. Sixty sexually adult males of A. lituratus were analyzed in this study, with five specimens collected monthly. Blood samples were submitted to serum hormone measurements and the prostates were morphologically, morphometrically, and immunohistochemically analyzed. The results indicated that the two prostatic regions (ventral and dorsal) of A. lituratus had different morphology, as well as different physiology and regulation. Annual fluctuations in abiotic factors seemed to influence the dorsal region more than the ventral region. Conversely, variations on testicular factors, such as testosterone and estradiol, influenced the ventral region more than the dorsal region. Despite these differences, both prostatic regions were strongly synchronized to the main reproductive peak of the species in September. The holocrine pattern of the ventral prostate was not directly affected by abiotic factors or by factors released by the testes.

The process of testicular regression also impacts the physiology of the epididymis of the bat Molossus molossus, although with a delay in epididymal response due to sperm storage.

Responsible for post-testicular maturation, concentration, protection and sperm storage, the epididymis is an organ that can be easily subdivided into three segments: caput, corpus and cauda. Each epididymal region displays different morphology and functions within the sperm maturation process. Despite the great importance of this organ, studies on its morphology and hormonal control in bats remain scarce. Thus, the aim of this study was to morphologically analyze the epididymis of the bat Molossus molossus (Chiroptera: Molossidae), in order to evaluate its morphological and morphometric variations, as well as some aspects of its hormonal control during the annual reproductive cycle. For this purpose, 60 sexually adult males were used in this study, comprising five specimens collected monthly for one year to form 12 sample groups. The epididymis was subjected to morphological, morphometric and immunohistochemical analyses. The results demonstrated that the processes of total testicular regression and posterior recrudescence suffered by M. molossus also impacts the physiology of the epididymis, however, a delay in the epididymal response is seen due to the storage of sperm. Similar to other mammals, the epididymis of M. molossus has a large predominance of principal and basal cells. The epididymal seasonal variations appear to be directly correlated to rainfall and photoperiod, but not to temperature. Meanwhile, epididymal physiology appears to be regulated, at least partially, by the expression of the androgen receptor in epithelial cells, which has agonist effects on cell proliferation.

The hormonal control of the uterus of the bat Myotis nigricans during its different reproductive phases: emphasis on progesterone and estradiol.

Myotis nigricans is a species of bat from the Vespertilionidae family that is endemic of the Neotropical region. Its insectivorous feeding habit plus its large range of prey species, great geographical dispersion, wide colonies, and anthropomorphized behavior make this species an important ecological agent that acts in the control of nocturnal insects. Reproductively, M. nigricans presents geographic variations, having different patterns of reproduction according to its geographical location. Despite these extremely interesting characteristics, no more detailed study of the hormonal control of the reproduction of this species has been conducted. Therefore, the aim of the present study was to evaluate the variations in serum hormone concentrations and in uterine hormonal control of this bat during its different reproductive phases. Twenty adult females were collected, divided into four (4) sample groups, according to the reproductive status (nonreproductive, initial, and advanced pregnancy and lactating), and submitted to hormone dosage and immunohistochemical analyses. The results demonstrated that the uterus of M. nigricans is strongly regulated by the interaction/cross-talk between serum concentrations of estradiol (E2) and progesterone with their respective hormone receptors. Significant increases in the concentration of E2 and progesterone are needed to regulate the early pregnancy. The persistence of the corpus luteum throughout pregnancy is necessary, since its placenta does not express aromatase. The expressions of ERα and PR appear to be synchronized in order to coordinate a large portion of the processes that occur inside the uterus of M. nigricans during pregnancy and lactation.

Annual reproductive cycle of males of the bat Molossusmolossus: Seasonal bimodal polyestry, testicular regression, and some aspects of the hormonal control.

Bats are mammals that play a fundamental role in the regulation of the ecosystems by, for example, controlling the insect populations. Therefore, insectivorous species, such as Molossusmolossus, have become the target of great scientific interest. Despite the different studies that exist on the species, there is still no consensus regarding its reproduction. Thus, this study aimed to analyze the morphophysiology and some aspects of the hormonal control of the testes of M. molossus (Chiroptera: Molossidae), by evaluating its morphological and morphometric variations throughout the annual reproductive cycle. Sixty sexually adult males of M. molossus were used in the study, with five specimens collected each month for one year, forming 12 sample groups. The testes of each bat were submitted to morphological, morphometric, and immunohistochemical analyses. Molossusmolossus presented an annual reproductive cycle with two peaks of spermatogenic activity, one in April and the other in September, and a period of total testicular regression in December, which has never been described. The cycle appeared to be regulated by rainfall and was, at least partially, controlled by the expression of the androgen receptor in Sertoli cells, which has agonist effects on cell proliferation.

Morphophysiological variations of the female reproductive organs of the vespertilionid bat Myotis nigricans during its different reproductive phases.

Myotis nigricans is an important species of insectivorous bat from the Vespertilionidae family, which is endemic of the Neotropics. Despite its wide distribution, no detailed study of the reproduction is found for this species. Thus, the aim of the present study was to evaluate and characterize morphological and morphometric variations of the female reproductive organs of M. nigricans during its different reproductive phases. Twenty adult females were collected, divided into four (4) sample groups, according to the reproductive status (nonreproductive, initial and advanced pregnancy and lactating), and submitted to anatomical, histological and morphometric analyses. The results demonstrated that the female reproductive organs of M. nigricans were composed of the ovaries, the uterus, the uterine tubes and the vagina, in addition to the mammary glands. The ovaries present a great number of interstitial glands and a small but persistent corpus luteum. Ovulation is simple, unilateral and non-preferential, possibly alternated in successive ovulations and may be sequential with the occurrence of postpartum estrus. The uterus is bicornuate, implantation is fundic and the placenta is chorioallantoic, discoidal and hemochorial. The vaginal epithelium is weakly keratinized and shows great disorganization during the periods of pregnancy and lactation.

Evaluation of the uterine hormonal control of the bat Artibeus lituratus during the different phases of its reproductive cycle.

Artibeus lituratus is a frugivorous bat that directly assists in the restoration of degraded habitats through the effective dispersion of seeds and fruits. Given its great importance, this work aimed to evaluate the uterine hormonal control of A. lituratus during its different reproductive phases. The uteri of 30 sexually mature adult females, five specimens for each of the six sample groups (NON, nonreproductive; P1, initial pregnancy; P2, intermediate pregnancy; P3, advanced pregnancy; LAC, lactating; P + LAC, pregnant-lactating), were submitted to analyses of serum estradiol and progesterone concentrations, in addition to immunohistochemical analyses. Both estradiol and progesterone, gradually increased during pregnancy, with a marked significant increase in P3 females. Both returned to low levels in LAC-females; however, estradiol levels decreased further in P + LAC-females, while progesterone increased in the same group. In general, signs indicative of aromatase expression were observed in the endometrium of all analyzed groups and in the placenta of bats in the gestation groups. Similarly, ERα and PR were expressed in the myometrium, endometrium and placenta at varying levels of intensity. The results indicate that the uterine microenvironment of A. lituratus is directly regulated by serum concentrations of estradiol and progesterone, and fluctuations in these concentrations control morphological and physiological changes of this organ during different phases of the reproductive cycle. RESEARCH HIGHLIGHTS: Increases in serum concentrations of estradiol and progesterone coordinate the gestational period of A. lituratus. Estradiol activates ERα, stimulating cell proliferation in the uterus, in addition to activating the expression of PR, which trigger the quiescence of the myometrium and stimulation of the secretion and differentiation of the endometrium. Results showed several similarities to humans, indicating the use of A. lituratus as an animal model in reproductive studies.

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

Artibeus lituratus is one of the most recognized bat species in the neotropics, probably due to its high abundance in urban areas. Despite its wide distribution, the morphology and physiology of its reproductive organs remain unclear. Thus, the aim of the present study was to describe the morphology and histology of the female reproductive organs of this species, and evaluate morphological variations during its different reproductive phases (nonreproductive, pregnant, lactating, etc.). Thirty adult females were collected, divided into six (6) sample groups, according to the reproductive status, and submitted to anatomical and histological analyses. We show that the ovaries of A. lituratus are polarized, present a low number of interstitial glands, have large and well-developed Graafian follicles and a persistent corpus luteum, and may present a functional everted corpus luteum. Ovulation is simple, unilateral and nonpreferential, possibly alternated in successive ovulations, and may be sequential, with the occurrence of postpartum estrus. The uterus is simplex, the implantation is fundic and interstitial and the placenta is chorioallantoic, discoidal, and hemochorial. The female reproductive organs of A. lituratus share similarities with the pattern observed in human, which indicates that A. lituratus may be an interesting animal model in reproductive studies.

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

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.

Structural, ultrastructural and immunohistochemical evidence of testosterone effects and its ablation on the bulbourethal gland of the Artibeus planirostris bat (Chiroptera, Mammalia).

This study evaluated the effects of testosterone in the bulbourethral glands (BG) of the bat, Artibeus planirostris, by performing castration and posterior hormonal supplementation of the animals. The results showed a decrease in testosterone levels in animals 15days after castration, which induced a small reduction in epithelium height, percentage of AR+ cells, and an increase in the amount of basal cells. This reduction became more severe in groups castrated for longer periods (19 and 22days), where there was also an increase in apoptotic cells. Moreover, the hormonal supplementation increased testosterone levels (after 3 and 7days of supplementation), causing a glandular reactivation that increased the epithelium height and AR expression. In conclusion, BG took longer to respond to ablation of testosterone than other reproductive glands, since it showed evident aspects of regression only in animals 22days after castrated.

Comparative analysis of the male reproductive accessory glands of bats Noctilio albiventris (Noctilionidae) and Rhynchonycteris naso (Emballonuridae).

In eutherian mammals, the male reproductive accessory glands (RAGs) comprise the prostate, bulbourethral glands, ampullary glands, and the seminal vesicles. Their composition, anatomy and function vary widely between species. This study aimed to characterize histologically and compare the RAGs of bats. The RAGs of Noctilio albiventris (Noctilionidae) and Rhynchonycteris naso (Emballonuridae) were studied using anatomical and histological methods, and were reconstructed three dimensionally. The RAGs of N. albiventris and R. naso are composed of a compact glandular complex that surrounds the urethra and a pair of bulbourethral glands, which are extra-abdominally located in the inguinal region. In both species, the glandular complex is composed of two well-defined prostatic regions (ventral and dorsal). The ventral region showed an atypical epithelium (holocrine), where no obvious cellular limits were observed, and PAS-positive secretion. The dorsal region had a pseudostratified cuboidal epithelium, with basal and secretory cells, and PAS-negative secretion. Noctilio albiventris also had urethral glands (Littre glands) surrounding the urethra, however, R. naso had only muscles. Both species had bulbourethral glands, with simple columnar epithelium and PAS-positive secretion. In conclusion, the RAGs of N. albiventris and R. naso comprised a pair of bulbourethral glands and an intra-abdominal complex, composed of a prostate with two different regions (ventral and dorsal), while the ampullary glands and seminal vesicles were missing in both species. This morphology was more closely related between N. albiventris and R. naso, and to species of the family Phyllostomidae than to families Molossidae and Vespertilionidae. J. Morphol. 277:1459-1468, 2016. © 2016 Wiley Periodicals, Inc.

Morphophysiology and ultrastructure of the male reproductive accessory glands of the bats Carollia perspicillata, Glossophaga soricina and Phyllostomus discolor (Chiroptera: Phyllostomidae).

The male reproductive accessory glands (RAGs) are important organs that contribute to the secretion of different substances that composed the ejaculate. Despite this important function, their composition, anatomy and function vary widely between species. Thus, the RAGs of three species of phyllostomid bats were morphologically and ultrastructurally characterized and compared in this study. The RAGs of the three analyzed species are composed of a prostate and a pair of bulbourethral glands (BG). In all species, the prostate is composed of three well-defined regions (ventral, dorsolateral and dorsal regions). The ventral region showed an atypical epithelium (undefined) with no obvious cellular limits and a holocrine PAS-positive secretion. The dorsolateral region of Carollia perspicillata and Phyllostomus discolor showed a pseudostratified cubic morphology, and that from Glossophaga soricina had a columnar morphology endowed with cytoplasmic projections and stereocilia. The dorsal region of the three analyzed species is composed of a pseudostratified columnar epithelium endowed with stereocilia; however, G. soricina also presented cytoplasmic projections in the apical portions of the secretory cells similar to those in the dorsolateral region. The BG of the three analyzed species are composed of a pseudostratified columnar epithelium including basal and PAS-positive secretory cells. In conclusion, this study morphologically and ultrastructurally characterized the RAGs of three species of phyllostomid bats, demonstrating the presence of a novel third prostatic region in species of this family. The results also showed the absence of seminal vesicles and ampullary glands, and better characterized the holocrine pattern of the prostatic ventral region, which is unique to bats.

The effects of castration followed testosterone supplementation in prostatic complex of Artibeus planirostris (Chiroptera: Phyllostomidae).

The prostatic complex (ventral and dorsal regions) of Artibeus planirostris exhibits seasonal variations throughout the year. Circulating testosterone was correlated with prostate weight, showing an increase from autumn to summer, with the highest peak in summer corresponding to the largest breeding season. This indicates that the level of serum testosterone influences variations in both testicular and prostatic weights. Serum testosterone levels seem to be closely related to the different responses of these glands throughout the year. The castration (consequent suppression of testosterone) and subsequent hormone supplementation may elucidate the relationship of these two glandular types with testosterone. Thus, the aim of this study was to evaluate the effect of castration and the testosterone supplementation in the male prostatic complex of A. planirostris. The results indicated that both prostatic regions were affected by the ablation of testosterone, presenting a decrease in cell proliferation and an increase in apoptosis. Similarly, the prostate was responsive to hormonal supplementation, having a recovery of the active morphophysiological pattern with testosterone supplementation. However, data have shown that the ventral region was more sensitive to changes in testosterone than the dorsal, presenting greater cell renewal.

Impact of the Processes of Total Testicular Regression and Recrudescence on the Epididymal Physiology of the Bat Myotis nigricans (Chiroptera: Vespertilionidae).

Myotis nigricans is a species of vespertilionid bat, whose males show two periods of total testicular regression within the same annual reproductive cycle in the northwest São Paulo State, Brazil. Studies have demonstrated that its epididymis has an elongation of the caudal portion, which stores spermatozoa during the period of testicular regression in July, but that they had no sperm during the regression in November. Thus, the aim of this study was to analyze the impact of the total testicular regression in the epididymal morphophysiology and patterns of its hormonal regulation. The results demonstrate a continuous activity of the epididymis from the Active to the Regressing periods; a morphofunctional regression of the epididymis in the Regressed period; and a slow recrudescence process. Thus, we concluded that the processes of total testicular regression and posterior recrudescence suffered by M. nigricans also impact the physiology of the epididymis, but with a delay in epididymal response. Epididymal physiology is regulated by testosterone and estrogen, through the production and secretion of testosterone by the testes, its conduction to the epididymis (mainly through luminal fluid), conversion of testosterone to dihydrotestosterone by the 5α-reductase enzyme (mainly in epithelial cells) and to estrogen by aromatase; and through the activation/deactivation of the androgen receptor and estrogen receptor α in epithelial cells, which regulate the epithelial cell morphophysiology, prevents cell death and regulates their protein expression and secretion, which ensures the maturation and storage of the spermatozoa.

Impact of the processes of testicular regression and recrudescence in the prostatic complex of the bat Myotis nigricans (Chiroptera: Vespertilionidae).

Myotis nigricans is a species of vespertilionid bat, whose males show two periods of total testicular regression during the annual reproductive cycle in the northwest São Paulo State, Brazil. Thus, the aim of this study was to investigate the impact of total testicular regression on the prostatic morphophisyology and its regulation. The prostatic complex (PC) of animals from the four periods of the reproductive cycle (active, regressing, regressed, and recrudescence) was analyzed by different histological, morphometric, and immunohistochemical procedures to characterize its variations, analyze its hormonal regulation and evaluate whether the prostate is affected by the processes of testicular regression and recrudescence. The results indicated a decrease in the prostatic parameters from the active to regressed periods, which are related to decreases in the testicular production of testosterone and in the prostatic expression of androgen receptor (AR), estrogen receptor α (ERα) and aromatase. However, in regressed-recrudescence periods, the prostatic expression of AR, ERα and aromatase increased, indicating the reactivation of the PC. Despite this, the PC appears to have a slower reactivation and seems not to follow the testicular recrudescence in morphological and morphometric terms. With these data, we demonstrate that the prostatic physiology is directly affected by total testicular regression and conclude that it is regulated by testosterone and estrogen, via the production of testosterone by the testes, its conversion to dihydrotestosterone by 5α-redutase and to estrogen by aromatase, and the activation/deactivation of AR and ERα in epithelial cells, which regulate cell expression and proliferation.

Comparative analysis of the male reproductive accessory glands of bat species from the five Brazilian subfamilies of the family Phyllostomidae (Chiroptera).

This study aimed to morphologically characterize and compare the male reproductive accessory glands (RAGs) of bats belonging to the five Brazilian subfamilies of the family Phyllostomidae (Carollia perspicillata-Carollinae; Desmodus rotundus-Desmodontinae; Glossophaga soricina-Glossophaginae; Phyllostomus discolor-Phyllostominae and Platyrrhinus lineatus-Stenodermatinae). The study demonstrated that the RAGs of phyllostomid bats were comprised of a pair of extra-abdominal bulbourethral glands and an intra-abdominal complex, composed of paraurethral glands and a prostate with two (Desmodontinae and Stenodermatinae) or three (Carollinae, Glossophaginae and Phyllostominae) different regions, with the absence of the seminal vesicles; this pattern possibly evolved from a process of compaction of the prostatic regions from an ancestor with three regions.

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

Due to their wide geographical distribution, bats suffer considerable influence from abiotic factors on their reproductive strategies, detected through behavioural or functional assessment of the gonads and accessory glands. The present study aimed to characterise anatomically and morphologically the reproductive accessory glands (RAGs) of Molossus molossus (Molossidae) and evaluate their seasonal variations. The RAGs were removed, fixed, sectioned after histological processing and submitted to the following stains: haematoxylin-eosin, periodic acid--Schiff (PAS) and Gömöri's reticulin. Our data demonstrated that the RAGs of M. molossus are composed of a semi-lobed prostatic complex associated with the urethra and a pair of inguinal bulbourethral glands. Histology and three-dimensional reconstruction of the prostatic complex demonstrated the existence of two regions: ventral and dorsal (named according to the position around the urethra). The two regions had distinctive morphological and histological differences, with the ventral region being the most prominent and the dorsal formed by four lobes. Considering the seasonal evaluation, we can infer that the prostatic complex of M. molossus is active throughout the seasons in São Paulo State (Brazil) and, although each of the prostatic regions has inherent characteristics, they synchronise to establish the main reproductive peak in spring (early rainy season).