Structure, histochemistry and ultrastructure of the male reproductive accessory glands in the neotropical flat-faced fruit-eating bat Artibeus planirostris (Chiroptera: Phyllostomidae)

Chiroptera, the second largest mammalian order, presents different reproductive strategies and unique reproductive features. However, there are few reports regarding male reproductive accessory glands (RAGs) in Chiroptera. Thus, the aim of the present study was to characterise the RAGs of the exclusively neotropical bat Artibeus planirostris (Chiroptera: Phyllostomidae) macroscopically, microscopically and ultrastructurally. The RAGs were composed of a prostatic complex with two regions (ventral and dorsal) and paraurethral and bulbourethral glands, but no seminal vesicles. The ventral region had an undefined epithelium, with secretory and basal cells, and its secretions were periodic acid-Schiff (PAS) positive. The dorsal region received both deferens ducts, had a columnar pseudostratified epithelium with secretory and basal cells. There were two types of secretions from the dorsal region: one that was basophilic and another that was mixed PAS positive and PAS negative. The paraurethral glands were dispersed in the connective tissue of the urethra, whereas the bulbourethral glands were located in the penile root. Histological and ultrastructural data confirmed the prostatic nature of the ventral and dorsal regions and the holocrine nature of the ventral region, with the latter finding never having been described previously for the prostate gland. Our findings demonstrate the wide discrepancy of RAGs between A. planirostris and other mammals in terms of their composition, structure and morphology. © CSIRO 2013.

Reproductive data of a threatened bat, Myotis ruber (E. Geoffroy, 1806) (Chiroptera, Vespertilionidae) in a southern Brazilian deciduous seasonal forest

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

SYSTEMATIC RELATIONSHIPS WITHIN CHIRODERMA (CHIROPTERA, PHYLLOSTOMIDAE) BASED ON CYTOCHROME-B SEQUENCE VARIATION

The Neotropical bat genus Chiroderma consists of five recognized species. This study uses DNA-sequence variation of the mitochondrial cytochrome b gene to infer the phylogenetic relationships within Chiroderma. Phylogenetic relationships deduced from these data by parsimony analyses resulted in the discovery of a single most-parsimonious tree with C. salvini diverging basal to the other four species of Chiroderma and sister-group relationships of C. villosum with C. improvisum and C. trinitatum with C. doriae. This is a relatively young group of species with approximate times of divergence ranging from 1.6 million years before present (mya) for the divergence of C. doriae from C. trinitatum to 4.6 mya for the divergence of C. salvini from the other four species of Chiroderma.

Análise ultraestrutural e imunocitoquímica da espermatogênese e nucleologênese de morcegos

Pós-graduação em Genética - IBILCE

The modularity of seed dispersal: differences in structure and robustness between bat- and bird-fruit networks

In networks of plant-animal mutualisms, different animal groups interact preferentially with different plants, thus forming distinct modules responsible for different parts of the service. However, what we currently know about seed dispersal networks is based only on birds. Therefore, we wished to fill this gap by studying bat-fruit networks and testing how they differ from bird-fruit networks. As dietary overlap of Neotropical bats and birds is low, they should form distinct mutualistic modules within local networks. Furthermore, since frugivory evolved only once among Neotropical bats, but several times independently among Neotropical birds, greater dietary overlap is expected among bats, and thus connectance and nestedness should be higher in bat-fruit networks. If bat-fruit networks have higher nestedness and connectance, they should be more robust to extinctions. We analyzed 1 mixed network of both bats and birds and 20 networks that consisted exclusively of either bats (11) or birds (9). As expected, the structure of the mixed network was both modular (M = 0.45) and nested (NODF = 0.31); one module contained only birds and two only bats. In 20 datasets with only one disperser group, bat-fruit networks (NODF = 0.53 +/- A 0.09, C = 0.30 +/- A 0.11) were more nested and had a higher connectance than bird-fruit networks (NODF = 0.42 +/- A 0.07, C = 0.22 +/- A 0.09). Unexpectedly, robustness to extinction of animal species was higher in bird-fruit networks (R = 0.60 +/- A 0.13) than in bat-fruit networks (R = 0.54 +/- A 0.09), and differences were explained mainly by species richness. These findings suggest that a modular structure also occurs in seed dispersal networks, similar to pollination networks. The higher nestedness and connectance observed in bat-fruit networks compared with bird-fruit networks may be explained by the monophyletic evolution of frugivory in Neotropical bats, among which the diets of specialists seem to have evolved from the pool of fruits consumed by generalists.

Pollen Dispersal Between Isolated Trees in the Brazilian Savannah: A Case Study of the Neotropical Tree Hymenaea stigonocarpa

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Morphological and morphometric characteristics of the epididymis in the Neotropical bats Eumops glaucinus and Molossus molossus (Chiroptera: Molossidae).

The ability of certain species of bats to store viable spermatozoa in the cauda epididymis, for periods of many months beyond the end of spermatogenesis was first recognized over a century ago. However, information about the bat epididymis is still scarce or absent. Thus, this study aimed to characterize and to compare morphologically and morphometrically the regional histology of the epididymis of Eumops glaucinus and Molossus molossus (Chiroptera: Molossidae). Histologically, the epididymis of both species was subdivided into 4 segments: initial segment, caput, corpus and cauda. In comparing the two species, it was observed that the tubular and luminal diameters and percentage of interstitial tissue showed significant differences in all segments. The epithelial height, in both, is greater in the initial segment with a decrease until the cauda epididymis. In relation to the luminal diameter, both species showed a gradual increase from the initial segment to the cauda. The percentage of epithelium, lumen and interstitial tissue varied between both, sometimes M. molossus showing a significantly higher percentage, and other times, E. glaucinus. In both species, the principal cell was the most abundant (> 77%), followed by basal cells at approximately 13% and apical cells at 4% in all segments. Spermatozoa were observed in greater amounts in corpus and cauda epididymis segments. In summary, ours results show that, despite that the species analyzed belong to different genera and have different breeding cycles, the epididymis exhibits similarities in the two species and morphometric and composition differences compared to the majority of mammals.

Bat community in a cave from eastern Brazil, including a new record of Lionycteris (Phyllostomidae, Glossophaginae)

A cave bat community from a semiarid region in eastern Brazil was studied during the dry season. A high diversity was observed, with thirteen species recorded. Except for Micronycteris minuta and Lionycteris spurrelli, these bats were also found in other Brazilian karstic areas. The commonest species were the hematophague Desmodus rotundus, the omnivore Carollia perspicillata, and the insectivore Natalus stramineus. The bats formed itinerant colonies, moving frequently inside the cave. L. spurrelli was previously known from Amazonia, usually associated with evergreen forests. The present record extends its range 1600 km to the south. A disjunct distribution explains some morphological differentiation between Amazonia and Olhos d'Agua cave populations. The latter may be a relict of former continuous forest vegetation, which has been fragmented after the climatic optimum. Dispersion through the Cerrado forest gallery is also possible.

Morphological Variation of Primary Reproductive Structures in Males of Five Families of Neotropical Bats

Bats present unique features among mammals with respect to reproduction, and although neotropical bats do not have a hibernation period, many of their reproductive characteristics vary seasonally and interspecifically. Thus, this work aimed to examine the reproductive structures of 18 species belonging to five families of Brazilian bats. The gross anatomy of the testes varied little; however, the epididymis of Emballonuridae and Vespertilionidae showed exceptional structures with a large elongation of the caudal region. We observed a wide variation in the positioning of the testes: Phyllostomidae and Noctilionidae presented external testes; Emballonuridae and Molossidae presented migratory testes that may be in intra-abdominal or external positions; and Vespertilionidae displayed scrotal testes. In the histological evaluation, we observed a different pattern in vespertilionid species, with testicular regression and sperm retention/storage in the cauda epididymis in the five species analyzed. Similar testicular regression was observed in Molossops temminckii; however, sperm retention/storage was not observed in this species. These data suggest that although the species analyzed are tropical species that do not present a prolonged period of torpor (hibernation), they still maintain a period of seminiferous tubule regression and sperm storage very similar to that observed in hibernating bats. © 2012 Wiley Periodicals, Inc.

Annual reproductive cycle of males of the flat-faced fruit-eating bat, Artibeus planirostris (Chiroptera: Phyllostomidae)

Artibeus planirostris is an endemic species of Phyllostomid bat from the Neotropical region. Some studies have indicated that it exhibits seasonal bimodal polyestry; however, others postulate that it may be able to produce young at any time during the year. Thus, the aim of this study was to evaluate the annual variations in testicular and epididymal parameters of this species in southeast Brazil and try to understand how the reproduction of this species is regulated in this environment. Sixty mature male specimens, collected between June 2009 and May 2010, were submitted to morphometric and immunohistochemical analysis. Our study showed that A. planirostris presented a continuously active pattern of spermatogenesis throughout the year, presenting spermatozoa inside its cauda epididymis in all months, but with two pronounced peaks of spermatogenic production, one in September and other in February. We propose that the males developed these two peaks in order to produce sufficient sperm for the reproduction in a harem system and to synchronize with the female reproductive cycle, which had a bimodal polyestric pattern. Control of this variation is directly linked to the expression of the androgen receptor (AR) in Sertoli cells and to serum testosterone levels, which appear to synchronize to establish these two peaks. In the months preceding the two peaks, the testis have a higher expression of the AR, which possibly stimulates the increase in PCNA, and drives a gradual increase in the testicular parameters. Taken together the results suggest that if sperm storage happens in this species, it is of short duration. © 2013 Elsevier Inc.

Ultrastructural characteristics of the spermatogenesis during the four phases of the annual reproductive cycle of the black myotis bat, Myotis nigricans (Chiroptera: Vespertilionidae)

Myotis nigricans 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 (Ad, Ap, 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 M. nigricans during the four different periods of its annual reproductive cycle. Microsc. Res. Tech., 76:1035-1049, 2013. © 2013 Wiley Periodicals, Inc.

Interindividual variations in fruit preferences of the yellow-shouldered bat Sturnira lilium (Chiroptera: Phyllostomidae) in a cafeteria experiment

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tree cavities used as diurnal roosts by Neotropical bats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)