Made available in DSpace on 2015-03-03T11:52:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-28Bitstream added on 2015-03-03T12:06:48Z : No. of bitstreams: 1 000802342_20150301.pdf: 1048498 bytes, checksum: a5ae32d8ee5c0b124476d60332f7798b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Chiroptera é a segunda maior ordem de mamíferos e possui distribuição mundial e, como consequência, apresenta uma grande diversidade de comportamento, hábito alimentar e estratégias reprodutivas. Entretanto, a maioria dos estudos relativos à reprodução é feita com espécies de morcegos de clima temperado, pouco se sabendo sobre a reprodução de morcegos de clima tropical. Vespertilionidae é a família que apresenta a maior distribuição dentro da Ordem. No Brasil, são referenciados cinco gêneros da família, entre eles, o gênero Eptesicus, com espécies exclusivamente insetívoras. São seis espécies brasileiras de Eptesicus, sendo essas simpátricas e com grande semelhança morfológica entre si, e para as quais há poucas informações sobre os aspectos reprodutivos e até mesmo sobre a variação morfológica, o que dificulta a identificação precisa de cada espécie. Eptesicus furinalis é a espécie que possui a maior distribuição entre as seis espécies brasileiras do gênero. Portanto, foram objetivos desse trabalho, analisar o processo da espermatogênese, o ciclo do epitélio seminífero e a ultraestrutura do espermatozoide, e analisar a variação morfológica do crânio, a morfologia do báculo e do cariótipo, contribuindo não só para o entendimento dos padrões reprodutivos das espécies de morcegos tropicais, mas também na taxonomia do gênero. O epitélio seminífero apresentou o padrão básico de mamíferos, e a espermiogênese pode ser dividida em sete estádios (na microscopia de luz) ou doze estádios (na microscopia eletrônica de transmissão), de acordo com os parâmetros da condensação e distribuição da cromatina e pelo método da formação do acrossomo, respectivamente. A espécie apresentou um processo de regressão testicular, similar ao observado em morcegos hibernantes de clima temperado, fato intrigante, uma vez que E. furinalis é uma espécie exclusivamente tropical e não hibernante ... / Chiroptera is the second largest mammalian order with worldwide distribution and, as a result, present a great diversity of reproductive strategies. Indeed, most studies on reproduction are performed with bat species from temperate zones, and little is known about the tropical bats reproduction. Vespertilionidae is the family with the largest distribution within the Order. Five genera occur in Brazil and among them there are the genus Eptesicus, with exclusively insectivorous species. Six species of Eptesicus occur in Brazil, and these are sympatric and has great morphological resemblance to each other, and there is little information on the reproductive aspects of them and even of morphological variation, making it difficult to accurately identify each species. E. furinalis is the most disperse species of Eptesicus in Brazil. Thus, the aims of this work was to analyse the process of spermatogenesis, the seminiferous epithelium cycle and the ultrastructure of the spermatozoon, and analyse the morphological variation of the skull, baculum and karyotype, in order to increase informations about the reproductive patterns of tropical bat species and about the taxonomy of Eptesicus. The semineferous epithelium showed the basic mammalian pattern and the spermiogenesis could be divided into seven steps (light microscopy) or twelve steps (PAS method and transmission elctron microscopy), when analyzed by the parameters of the chromatin distribution and condensation and by the acrosome method, respectively. E. furinalis showed a process of testicular regression similar to testicular regression in hibernating bats of temperate zones, which is an intriguing fact, since E. furinalis is an exclusive tropical species and does not hibernates. The seminiferous epithelium cycle presented no fixed cell associations throughout the seminiferous tubule, as is expected in mammals, however, exhibited eight frequent stages when analyzed by the tubular morpholoy ...

Historically, physiologists have believed steroid hormones act exclusively within the individual producing them. However, studies in mice have shown that bioactive 17β-estradiol (E2) is excreted in male urine and absorbed by female conspecifics where it binds to estrogen receptors in reproductive other tissues. This can lead to pregnancy disruption and/or cause precocious puberty in female conspecifics. In bats the transfer of tritium-labelled estradiol (3H-E2) from male to females has been shown during the mating season. I investigated the influence of season on 3H-E2 transfer and showed that females housed with 3H-E2 injected males had significantly higher levels of radioactivity in reproductive, neural, and peripheral tissues during reproductively relevant timepoints compared to the non-reproductive season. Because urine has been hypothesized as the vector of steroid hormone transmission in mice, I examined the natural patterns of sex steroids in the urine of male and female big brown bats (Eptesicus fuscus) across the annual reproductive cycle. I found that creatinine-adjusted E2, which corrects for animal hydration and activity, was significantly higher in male than female urine, and in adult compared to yearling urine. Seasonal differences in urinary E2 levels were observed within and between sexes. Finally, I designed a protocol to investigate the attractant properties of body odour and urine between bat sexes during the mating season. Using a two-alternative Y-maze arena, I found that female bats first approach the test arm containing urine of a male conspecific before exploring the arm with female urine. Females also tended to spend more time in the test-arm containing male urine and being in the male test-arm at the conclusion of the 5 min trial. My data supports the hypothesis that E2 has the potential to act as reproductive pheromone with urine as a likely vector. Given the close proximity of individual bats within a maternity roost, steroid hormone transfer between conspecifics quite likely occurs in nature and could have profound influences on female reproductive behaviour (e.g. receptivity) and physiology (e.g. estrus cycling). My research provides new evidence for the potential pheromonal actions of E2 in bats that is consistent with how sex steroids act as pheromones in other mammals. / Dissertation / Doctor of Philosophy (PhD) / Historically, physiologists have believed steroid hormones act exclusively within the individual producing them. However, studies in mice have shown that bioactive 17β-estradiol (E2) is excreted in male urine and absorbed by female conspecifics where it binds to estrogen receptors in reproductive and other tissues. This exogenous E2 can result in changes to female reproductive physiology and behaviour. Our lab has previously observed E2 to transfer between male and female captive big brown bats during the mating season. Research from this thesis provides evidence that the transfer of E2 from male to female bats is highest during times of mating and ovulation/fertilization. I also demonstrate that E2 naturally occurs in the urine of both male and females with age, sex, and seasonal differences in concentration. Lastly, I show that female bats are attracted to the urine of males. My research provides new evidence for the potential pheromonal actions of E2 in bats that is consistent with how sex steroids act as pheromones in other mammals.

<p>Developing bat pups produce distinct vocalizations called isolation calls (I‐calls) that serve to attract the bat’s mother. How individual pups shift their vocalizations from I‐calls to downward frequency modulated (FM) sweeps during development remains unclear. By recording individual bat pups from the day of birth to twenty‐five days postnatal we observed behavioural and bioacoustic (temporal and spectral) changes in pup calls. Temporal characteristics examined were call duration and call rate; spectral characteristics were minimum frequency, maximum frequency, peak spectral frequency, total signal bandwidth, maximum frequency of the fundamental acoustic element and bandwidth of the fundamental. I‐calls were produced only until a certain point in development, after which pups change from emitting long‐duration, tonal I‐calls to downward FM signals and eventually short‐duration biosonar vocalizations. We discovered additional spectral changes in the harmonic structure of pup calls, with the number of harmonic elements decreasing with age. We also recorded pup vocalizations during prolonged separation from their mothers to determine if extended isolation alters the type, number or acoustic structure of emitted vocalizations. Rate of calling was influenced by prolonged separation; younger pups had higher calling rates and called longer than older pups. We also compared temporal and spectral characteristics of spontaneous and provoked calls. We found that provoked calls were more similar to vocalizations produced by younger pups. By documenting the vocal behaviour and acoustic structure of pups calling in different situations, this research provides groundwork for further studies on the ontogeny and development of FM vocalizations in bats and other mammals.</p> / Master of Science (MSc)

No description available.

Bat populations across North America are either facing new threats from white-nose syndrome (WNS) and wind energy development or have already experienced precipitous declines. Accordingly, researchers and managers need to know how to best monitor bats to document population and distribution changes, as well as where to look for persisting populations. Landscape-scale WNS impacts to summer bat populations are not well understood, and although acoustic monitoring is commonly used to monitor these populations, there is limited information about differences among acoustic detectors and the implications to managers thereof. My objectives were to model the relationship between WNS impact, influence of available hibernacula, and environmental factors for summer nightly presence of three WNS-affected bats and to compare how multiple models of acoustic detectors perform in terms of detection probability and nightly recorded bat activity. I collected acoustic data from 10 study areas across Virginia, West Virginia, Ohio and Kentucky to describe changes in nightly presence of WNS-affected bat species during summer 2017. During the same period of time, I compared five types of acoustic detectors at Fort Knox, Kentucky. My results show the potential efficacy of using a WNS impact-year metric to predict summer bat presence, and highlight which environmental variables are relevant for large-scale acoustic monitoring. Additionally, my findings suggest that each of the detector types tested would suffice for most research and monitoring activities, but standardization of detector type within the scope of a project or study should be encouraged. / Master of Science / Bat populations across North America are either facing new threats from white-nose syndrome (WNS) and wind energy development or have already experienced devastating declines. Accordingly, wildlife biologists need to know how to best monitor bats to document population and distribution changes, as well as where to look for remaining populations. Landscape-scale WNS impacts to summer bat populations are not well understood, and although acoustic technology is commonly used to monitor these populations, there is limited information about differences among acoustic detectors and the implications to managers thereof. My objectives were to model the relationship between WNS impact, influence of available bat hibernation caves, and environmental factors for summer nightly presence of three WNS-affected bats and to compare how multiple models of acoustic detectors perform in terms of detection probability and nightly recorded bat activity. I collected acoustic data from 10 study areas across Virginia, West Virginia, Ohio and Kentucky to describe changes in nightly presence of WNS-affected bat species during summer 2017. During the same period of time, I compared five types of acoustic detectors at Fort Knox, Kentucky. My results show potential viability of a WNS impact-year metric to predict summer bat presence, and highlight which environmental variables are relevant for large-scale acoustic monitoring. Additionally, my findings suggest that each of the detector types tested would suit most research and monitoring activities, but standardization of detector type within the scope of a project or study should be encouraged.

Bats occupy diverse and unique niches and are regarded as important components in maintaining ecosystem health. They are major consumers of nocturnal insects, serve as pollinators, seed disperser, and provide important economic benefits as consumers of agricultural and forest pest insects. Bats have been proposed as good indicators of the integrity of natural communities because they integrate a number of resource attributes and may show population declines quickly if a resource attribute is missing. Establishing community- and population-level data, and understanding species interactions is especially important in changing landscapes and for species whose populations levels are threatened by outside factors of anthropomorphic disturbance from hibernacular visitation to energy production and fungal pathogens. For these reasons I have set out to establish habitat use patterns, detection probabilities, spatial and temporal occupancy, and investigate species interactions. This thesis is broken down into three distinct chapters each intended to be a stand-alone document. The first establishes the basic ecology from natural history accounts, provides an overview of the various sampling strategies, and gives a comprehensive description of the study area. The seconds sets out to identify the factors influencing detection probabilities and occupancy of six sympatric bats species and provide insight into habitat use patterns. The third examines spatial and temporal activity patterns and investigates species interactions. This study can provide understanding into the secretive and poorly understood patterns of free flying bats across the landscape. It can also deliver useful information to land managers regarding potential changes in landscape practices for the conservation of bat species. / Master of Science

Le syndrome du museau blanc (SMB), causé par le champignon Pseudogymnoascus destructans (Pd), a mis en péril les populations de chauves-souris hibernantes en Amérique du Nord. Certaines espèces sont hautement vulnérables à la maladie alors que d’autres espèces semblent être résistantes ou tolérantes à l’infection. Plusieurs facteurs physiologiques et environnementaux peuvent expliquer ces différences. Or avant 2015, peu d’études avaient porté sur le microbiome de la peau en relation avec cette maladie. La présente thèse vise à caractériser le microbiome cutané de chiroptères affectés par le SMB afin d’identifier les facteurs de vulnérabilité ou de résistance à la maladie. L’objectif principal est de déterminer comment le microbiome est affecté par la maladie ainsi que de déterminer si celui-ci à un rôle dans la protection face à l’infection fongique. Au Chapitre 1, nous avons tout d’abord exploré et comparé le microbiote cutané de petites chauves-souris brunes (Myotis lucifugus) non affectées par le SMB avec celui de chauves-souris survivantes au SMB pour tester l’hypothèse selon laquelle le microbiote cutané est modifié par la maladie. Nos résultats montrent que le site d’hibernation influence fortement la composition et la diversité du microbiote cutané. Les sites d’hibernations Pd positifs et négatifs diffèrent significativement en termes de diversité, ainsi qu’en termes de composition du microbiote. La diversité est réduite au sein du microbiote des chauves-souris survivantes au SMB et enrichi en taxons tels que Janthinobacterium, Micrococcaceae, Pseudomonas, Ralstonia et Rhodococcus. Certains de ces taxons sont reconnus pour leur potentiel antifongique et des souches spécifiques de Rhodococcus et de Pseudomonas peuvent inhiber la croissance de Pd. Nos résultats sont cohérents avec l’hypothèse selon laquelle l’infection par Pd modifie le microbiote cutané des chauves-souris survivantes et suggèrent que le microbiote peut jouer un rôle de protection face au SMB. Au Chapitre 2, nous avons étudié le microbiote d’une espèce résistante au champignon Pd en milieu contrôlé avant et après infection afin d’établir la réponse potentielle à la maladie. L’espèce étudiée est la grande chauve-souris brune (Eptesicus fuscus) dont le microbiote cutané pourrait jouer un rôle de protection contre l’infection. Nos résultats montrent que la diversité du microbiote de la grande chauve-souris brune inoculée avec Pd est plus variable dans le temps, tandis que la diversité du microbiote des chauves-souris du groupe contrôle demeure stable. Parmi les taxons les plus abondants, Pseudomonas et Rhodococcus, deux taxons connus pour leur potentiel antifongique contre Pd et d’autres champignons, sont restés stables durant l’expérience. Ainsi, bien que l’inoculation par le champignon Pd ait déstabilisé le microbiote cutané, les bactéries aux propriétés antifongiques n’ont pas été affectées. Cette étude est la première à démontrer le potentiel du microbiote cutané d’une espèce de chauves-souris pour la résistance au SMB. Au Chapitre 3, le microbiome cutané de la petite chauve-souris brune a été évalué en milieu naturel dans le contexte du SMB, à l’aide de la métagénomique, une approche haute résolution pour observer le potentiel fonctionnel du microbiome (métagénome fonctionnel). Nos résultats ont permis d’établir que le temps depuis l’infection a un effet significatif sur le métagénome fonctionnel. En effet, les chauves-souris dans la première année suivant l’infection ont un métagénome fonctionnel perturbé qui subit une perte de diversité fonctionnelle importante. Toutefois, le métagénome fonctionnel revient à une structure et composition similaire d’avant infection après 10 ans. Certaines fonctions détectées suite à l’infection sont associées à des gènes reliés au transport et à l’assimilation de métaux, des facteurs limitants pour la croissance du champignon. Ces gènes pourraient donc avoir un rôle à jouer dans la résistance ou la vulnérabilité à la maladie. Globalement, l’étude du métagénome chez la petite chauve-souris brune indique une vulnérabilité du métagénome fonctionnel au champignon, mais que celui-ci semble se rétablir après 10 ans. Une telle réponse pourrait avoir un impact sur la résilience de M. lucifugus. Cette thèse a permis d’acquérir des connaissances fondamentales sur le microbiome cutané des chauves-souris en hibernation pour mieux comprendre les communautés microbiennes de la peau dans le contexte du SMB. Le microbiome pourrait en effet jouer un rôle dans la vulnérabilité et la résistance des chauves-souris à la maladie, et il est essentiel d’adapter notre façon d’aborder la protection de ces espèces et de leur microbiome. Nous souhaitons que les travaux de cette thèse permettent de sensibiliser les acteurs de la conservation à l’existence et à l’importance potentielle du microbiome pour la santé de son hôte. Cette thèse fait également état de l’avancement des méthodes d’analyses qui permettront d’être de plus en plus précis et d’appliquer les connaissances du microbiome en biologie de la conservation. / White-nose syndrome (WNS) caused by the fungus Pseudogymnoascus destructans (Pd) has put hibernating bat populations at risk in North America. Some species are highly vulnerable to the disease while other species appear to be resistant or tolerant. Several physiological and environmental factors can explain these differences. However, before 2015, few studies have focused on the skin microbiome in relation to this disease. The present thesis aims to characterize the cutaneous microbiome of bats affected by WNS in order to identify the factors of vulnerability or resistance to the disease. The main objective is to determine how the microbiome can protect against the Pd fungus, or conversely how the microbiome is altered by the fungal infection. In Chapter 1, we first explored and compared the skin microbiota of little brown bats (Myotis lucifugus) unaffected by WNS with that of WNS survivors to test the hypothesis that the skin microbiota is modified by the disease. Our results show that the hibernation site strongly influences the composition and diversity of the skin microbiota. The Pd positive and negative sites differ significantly in terms of diversity, as well as in terms of the composition of the microbiota. Diversity is reduced within the microbiota of bats surviving WNS and enriched in taxa such as Janthinobacterium, Micrococcaceae, Pseudomonas, Ralstonia, and Rhodococcus. Some of these taxa are recognized for their antifungal potential and specific strains of Rhodococcus and Pseudomonas may inhibit the growth of Pd. Our results are consistent with the hypothesis that Pd infection modifies the skin microbiota of surviving bats and suggest that the microbiota may play a protective role against WNS. In Chapter 2, we studied in a controlled environment the microbiota of a species that exhibits evidence of resistance with mild WNS symptoms, before and after infection, to establish the potential response to the disease. The species studied is the big brown bat (Eptesicus fuscus), whose skin microbiota could play a protective role against infection. Our results show that the diversity of the microbiota of big brown bats inoculated with Pd is more variable over time, while the diversity of the microbiota of the control bats remains stable. Among the most abundant taxa, Pseudomonas and Rhodococcus, two taxa known for their antifungal potential against Pd and other fungi, remained stable during the experiment. Thus, although inoculation with the Pd fungus destabilized the skin microbiota, bacteria with antifungal properties were not affected. This study is the first to demonstrate the potential of the skin microbiota of a bat species for resistance to WNS. In Chapter 3, the skin microbiome of the little brown bat was evaluated in the natural environment in the context of WNS, using metagenomics, a higher-resolution approach to observe the functional potential of the microbiome (functional metagenome). Our results established that the time since infection has a significant effect on the functional metagenome. Indeed, bats in the first year after infection have a disrupted functional metagenome that undergoes a significant loss of functional diversity. However, the functional metagenome returns to a similar structure and composition to that observed before infection after 10 years. Certain functions detected following infection are associated with genes linked to the transport and assimilation of metals, known limiting factors for the growth of the fungus. These genes could therefore have a role to play in resistance or vulnerability to the disease. Overall, this metagenomics study indicates functional metagenome vulnerability to the fungus, although the original functional metagenome is reestablished after 10 years. Such diversified response could impact M. lucifugus resilence. This thesis provides fundamental knowledge on the skin microbiome of hibernating bats to better understand the microbial communities of the skin in the context of WNS. The microbiome could indeed play a role in the vulnerability and resistance of bats to disease and it is essential to adapt our way of approaching the protection of these species and their microbiomes. We hope that the results of this thesis will raise awareness among conservation stakeholders about the existence and potential importance of the microbiome for the health of its host. This thesis also reports on the advancement of analytical methods that will make it possible to be more and more precise and to apply knowledge of the microbiome in conservation biology.