RESUMO
Recent studies suggest that coronaviruses circulate widely in Southeast Asian bat species and that the progenitors of the SARS-Cov-2 virus could have originated in rhinolophid bats in the region. Our objective was to assess the diversity and circulation patterns of coronavirus in several bat species in Southeast Asia. We undertook monthly live-capture sessions and sampling in Cambodia over 17 months to cover all phases of the annual reproduction cycle of bats and test specifically the association between their age and CoV infection status. We additionally examined current information on the reproductive phenology of Rhinolophus and other bat species presently known to occur in mainland southeast China, Vietnam, Laos and Cambodia. Results from our longitudinal monitoring (573 bats belonging to 8 species) showed an overall proportion of positive PCR tests for CoV of 4.2% (24/573) in cave-dwelling bats from Kampot and 4.75% (22/463) in flying-foxes from Kandal. Phylogenetic analysis showed that the PCR amplicon sequences of CoVs (n = 46) obtained clustered in Alphacoronavirus and Betacoronavirus. Interestingly, Hipposideros larvatus sensu lato harbored viruses from both genera. Our results suggest an association between positive detections of coronaviruses and juvenile and immature bats in Cambodia (OR = 3.24 [1.46-7.76], p = 0.005). Since the limited data presently available from literature review indicates that reproduction is largely synchronized among rhinolophid and hipposiderid bats in our study region, particularly in its more seasonal portions (above 16° N), this may lead to seasonal patterns in CoV circulation. Overall, our study suggests that surveillance of CoV in insectivorous bat species in Southeast Asia, including SARS-CoV-related coronaviruses in rhinolophid bats, could be targeted from June to October for species exhibiting high proportions of juveniles and immatures during these months. It also highlights the need to develop long-term longitudinal surveys of bats and improve our understanding of their ecology in the region, for both biodiversity conservation and public health reasons.
Assuntos
Alphacoronavirus/genética , Betacoronavirus/genética , COVID-19/transmissão , Quirópteros/crescimento & desenvolvimento , SARS-CoV-2/genética , Alphacoronavirus/classificação , Animais , Sudeste Asiático/epidemiologia , Betacoronavirus/classificação , COVID-19/epidemiologia , COVID-19/virologia , Camboja/epidemiologia , Quirópteros/classificação , Quirópteros/virologia , Epidemias/prevenção & controle , Evolução Molecular , Genoma Viral/genética , Geografia , Humanos , Estudos Longitudinais , Masculino , Filogenia , SARS-CoV-2/classificação , SARS-CoV-2/fisiologia , Especificidade da EspécieRESUMO
Bats have been identified as the natural hosts of several emerging zoonotic viruses, including paramyxoviruses, such as Hendra and Nipah viruses, that can cause fatal disease in humans. Recently, African fruit bats with populations that roost in or near urban areas have been shown to harbour a great diversity of paramyxoviruses, posing potential spillover risks to public health. Understanding the circulation of these viruses in their reservoir populations is essential to predict and prevent future emerging diseases. Here, we identify a high incidence of multiple paramyxoviruses in urine samples collected from a closed captive colony of circa 115 straw-coloured fruit bats (Eidolon helvum). The sequences detected have high nucleotide identities with those derived from free ranging African fruit bats and form phylogenetic clusters with the Henipavirus genus, Pararubulavirus genus and other unclassified paramyxoviruses. As this colony had been closed for 5 years prior to this study, these results indicate that within-host paramyxoviral persistence underlies the role of bats as reservoirs of these viruses.
Assuntos
Quirópteros/virologia , Reservatórios de Doenças/virologia , Paramyxovirinae/fisiologia , Animais , Quirópteros/crescimento & desenvolvimento , Quirópteros/urina , Feminino , Masculino , Paramyxovirinae/classificação , Paramyxovirinae/genética , Paramyxovirinae/isolamento & purificação , Filogenia , Urina/virologiaRESUMO
We evaluated the structure of a community of frugivorous bats using composition and abundance patterns, niche amplitude and food overlap of these animals in four Atlantic Forest fragments, each one exposed to different conservation realities. For twelve months, we captured six bat species and found the seeds of 13 species of pioneering plants in 158 fecal samples. The most abundant bat species were Artibeus planirostris (25.4%), Artibeus lituratus (24.1%) and Carollia perspicillata(23.9%). Only one fragment (Fazenda Unida), the most conserved area, exhibited a significantly different composition and abundance of species. We found low trophic niche amplitude values (<0.60), associated to high food overlaps. Our results suggest that bats can adjust their foraging strategy to deal with food availability variations. By favoring pioneering plant species, the fragmentation process noted of the studied areas creates an attractive environment for bats more tolerant to this type of disturbance. The sampled areas represent important secondary forest remnants in southern Brazil that require attention to avoid an even greater loss of bat diversity.
Assuntos
Animais , Cadeia Alimentar , Quirópteros/anatomia & histologia , Quirópteros/crescimento & desenvolvimentoRESUMO
Rabies transmitted by common vampire bats (Desmodus rotundus) has been known since the early 1900s but continues to expand geographically and in the range of species and environments affected. In this review, we present current knowledge of the epidemiology and management of rabies in D. rotundus and argue that it can be reasonably considered an emerging public health threat. We identify knowledge gaps related to the landscape determinants of the bat reservoir, reduction in bites on humans and livestock, and social barriers to prevention. We discuss how new technologies including autonomously-spreading vaccines and reproductive suppressants targeting bats might manage both rabies and undesirable growth of D. rotundus populations. Finally, we highlight widespread under-reporting of human and animal mortality and the scarcity of studies that quantify the efficacy of control measures such as bat culling. Collaborations between researchers and managers will be crucial to implement the next generation of rabies management in Latin America.
Assuntos
Quirópteros/virologia , Reservatórios de Doenças/virologia , Vírus da Raiva/fisiologia , Raiva/virologia , Animais , Quirópteros/crescimento & desenvolvimento , Humanos , América Latina , Raiva/transmissão , Vírus da Raiva/genéticaRESUMO
Introduction: Reproduction is a critical phase for most living organisms and in bats the reproductive strategies exhibit considerable complexity and variability. Objective: To describe the reproductive patterns and population dynamics of seven bat species (Artibeus toltecus, Carollia perspicillata, Glossophaga soricina, Mormoops megalophylla, Pteronotus fulvus, Pteronotus mesoamericanus and Natalus mexicanus) that roost in one mine (La Mina) and two caves (El Apanguito and Cerro Huatulco) in the State of Oaxaca, in Southeastern México. Methods: Sampling was conducted monthly from July 2016 to June 2017. Bats were captured using a harp trap, which was placed at the entrance of the roosts. The captured bats were identified using taxonomic keys, marked with an aluminum ring, sex and age class were also determined. Reproductive activity was modeled through 63 GLMs for each species (504 in total). The best model was selected according to the Akaike Information Criterion (AIC). Results: A total of 5 836 bats were captured and marked, classified into 14 species, 10 genera, and five families. The most abundant species were: P. fulvus and P. mesoamericanus, representing 41 % and 32.3 % of the captures, respectively. The mormopids M. megalophylla, P. fulvus, P. mesoamericanus,together with N. mexicanus showed a restricted seasonal monoestrous pattern, while the phyllostomids A. toltecus, C. perspicillata, and G. soricina showed a seasonal bimodal polyoestry pattern. The monthly abundance of species fluctuated significantly (H= 13, df= 11, P= 0.044) in the three roosts throughout the entire study period and the best supported GLM that included the seven species showed that the six chosen variables (season, sex, roost, temperature, precipitation and humidity) were positively associated with reproductive activity. Conclusions: The reproductive activity of each species seems to be synchronized with the end of the dry season and the beginning of the rainy season, as well as influenced by factors such as temperature, humidity and roost site.
Introducción: La reproducción es una fase crítica para la mayoría de los organismos vivos y en los murciélagos las estrategias reproductivas exhiben considerable complejidad y variabilidad. Objetivo: Describir los patrones reproductivos y la dinámica poblacional de siete especies de murciélagos: Artibeus toltecus, Carollia perspicillata, Glossophaga soricina, Mormoops megalophylla, Pteronotus fulvus, Pteronotus mesoamericanus y Natalus mexicanus, que se refugian en una mina (La Mina) y dos cuevas (El Apanguito y Cerro Huatulco), en el estado de Oaxaca, sureste de México. Métodos: El muestreo se realizó una vez al mes de julio 2016 a junio 2017. Los murciélagos se capturaron utilizando una trampa de arpa que fue colocada en la entrada de los refugios. La especie de los murciélagos capturados fue determinada con claves de identificación taxonómica, además fueron marcados con un anillo de aluminio y también se determinó el sexo y la clase de edad. La actividad reproductiva fue modelada a través de 63 GLMs para cada especie (504 en total). El mejor modelo fue seleccionado según el Criterio de Información de Akaike (AIC). Resultados: Se capturaron y marcaron 5 836 murciélagos, incluidos en 14 especies, 10 géneros y cinco familias. Las especies más abundantes fueron: P. fulvus y P. mesoamericanus, que representaron el 41 y el 32.3 % de las capturas, respectivamente. Los mormópidos M. megalophylla, P. fulvus, P. mesoamericanus junto con N. mexicanus mostraron un patrón monoéstrico estacional,mientras que los filostómidos A. toltecus, C. perspicillata y G. soricina mostraron un patrón poliéstrico estacional bimodal. La abundancia mensual de las especies fluctuó significativamente (H= 13, df= 11, P= 0.044) en los tres refugios a lo largo del periodo de estudio y el GLM mejor respaldado que incluyó las siete especies mostró que las seis variables elegidas (temporada, sexo, refugio, temperatura, precipitación y humedad) se asociaron positivamente con la actividad reproductiva. Conclusiones: La actividad reproductiva de cada especie parece estar sincronizada con el final de la temporada seca y el comienzo de la temporada de lluvias, e influenciada por factores como temperatura, humedad y el sitio de refugio.
Assuntos
Animais , Quirópteros/classificação , Reprodução , Quirópteros/crescimento & desenvolvimento , Cavernas , MéxicoRESUMO
Bats use a large repertoire of calls for social communication, which are often characterized by temporal amplitude and frequency modulations. As bats are considered to be among the few mammalian species capable of vocal learning, the perception of temporal sound modulations should be crucial for juvenile bats to develop social communication abilities. However, the post-natal development of auditory processing of temporal modulations has not been investigated in bats, so far. Here we use the minimally invasive technique of recording auditory brainstem responses to measure the envelope following response (EFR) to sinusoidally amplitude modulated noise (range of modulation frequencies: 11-130 Hz) in three juveniles (p8-p72) of the bat, Phyllostomus discolor. In two out of three animals, we show that although amplitude modulation processing is basically developed at p8, EFRs maturated further over a period of about two weeks until p33. Maturation of the EFR generally took longer for higher modulation frequencies (87-130 Hz) than for lower modulation frequencies (11-58 Hz).
Assuntos
Percepção Auditiva , Tronco Encefálico/crescimento & desenvolvimento , Quirópteros/crescimento & desenvolvimento , Audição , Estimulação Acústica , Fatores Etários , Animais , Potenciais Evocados Auditivos do Tronco Encefálico , Feminino , Masculino , Fatores de TempoRESUMO
Wildfire is an important ecological process that influences species' occurrence and biodiversity generally. Its effect on bats is understudied, creating challenges for habitat management and species conservation as threats to the taxa worsen globally and within fire-prone ecosystems. We conducted acoustic surveys of wildfire areas during 2014-2017 in conifer forests of California's Sierra Nevada Mountains. We tested effects of burn severity and its variation, or pyrodiversity, on occupancy and diversity for the 17-species bat community while accounting for imperfect detection. Occupancy rates increased with severity for at least 6 species and with pyrodiversity for at least 3. Two other species responded negatively to pyrodiversity. Individual species models predicted maximum occupancy rates across burn severity levels but only one species occurred most often in undisturbed areas. Species richness increased from approximately 8 species in unburned forests to 11 in pyrodiverse areas with moderate- to high-severity. Greater accessibility of foraging habitats, as well as increased habitat heterogeneity may explain positive responses to wildfire. Many bat species appear well adapted to wildfire, while a century of fire suppression and forest densification likely reduced habitat quality for the community generally. Relative to other taxa, bats may be somewhat resilient to increases in fire severity and size; trends which are expected to continue with accelerating climate change.
Assuntos
Quirópteros/crescimento & desenvolvimento , Conservação dos Recursos Naturais/métodos , Incêndios Florestais , Animais , Quirópteros/classificação , Mudança Climática , Ecossistema , Densidade Demográfica , Especificidade da EspécieRESUMO
During mammalian pregnancy and lactation, the maternal demand for calcium is increased to satisfy fetus and newborn skeletal growth. In addition to the dietary intake, females use the calcium contained in their bones to supply this increased demand, leading to a decrease in maternal bone mineral content. In reproductive insectivorous female bats, bone loss has been described as a physiological cost of reproduction, due to the reported increased risk of bone fracture. This physiological cost may be the mechanism underlying the conflict between increasing litter size and maintaining wing skeletal integrity, which would help to explain the small litter size of most bat species. If bone loss is a linking cost between reproduction and survival in bats, and most bat species have small litter sizes, one would expect to find a loss of bone and an increasing probability of bone fracture during pregnancy and lactation in other non-insectivorous bats. In this study, we tested for the existence of this cost in the Great-fruit eating bat, Artibeus lituratus. We analyzed trabecular structure, bone strength and bone mineral content for the humerus bone, hypothesizing that bone loss during reproduction in females would increase the risk of fracture. Our results showed a decrease of 22-31% in bone trabecular area in lactating females, rapidly compensated following weaning. Bone strength did not differ among reproductive and non-reproductive groups and seems to be more influenced by bone organic components rather than mineral contents. Since we observed bone loss during reproduction yet the humerus strength seems to be unaffected, we suggest that bone loss may not represent a physiological cost during reproduction for this frugivorous bat.
Assuntos
Osso Esponjoso/metabolismo , Quirópteros/fisiologia , Reprodução/fisiologia , Animais , Peso Corporal , Densidade Óssea , Osso Esponjoso/química , Osso Esponjoso/patologia , Quirópteros/crescimento & desenvolvimento , Força Compressiva , Feminino , Lactação , GravidezRESUMO
Most morphological and physiological adaptations associated with bat flight are concentrated in the postcranium, reflecting strong functional demands for flight performance. Despite an association between locomotory diversity and trophic differentiation, postcranial morphological diversity in bats remains largely unexplored. Evolutionary developmental biology is a novel approach providing a link between the analysis of genotypic and phenotypic variation resulting from selective pressures. To quantify the morphological diversity of the postcranium in bats and to explore its developmental basis, we reconstructed the postcranial allometric trajectories of nine bat species from different prenatal developmental series, representing five families and both suborders. We tested for allometric growth in Chiroptera and also quantified levels of allometric disparity and inter-trajectory distances. Using a phylogenetic scaffold, we assessed whether ontogenetic differences reflect evolutionary relationships. We found significant allometric growth trajectories in almost all species. Interspecific trajectory distances showed lower variance within Yinpterochiroptera than within Yangochiroptera and between suborders. Each suborder occupied nonoverlapping sections of allometric space, showing changes in the growth rates of specific bones for each suborder. The allometry-corrected disparity was significantly higher in larger species. Statistically significant phylogenetic signal in our results suggests that there is an ontogenetic basis for the postcranial morphological diversity in modern bats. Ancestral state reconstruction also showed an increase in the amount of change in shape with size in the larger species studied. We hypothesize that differences in allometric patterns among bat taxa may reflect a size-dependent evolutionary constraint, whereby variability in body size and allometric patterns are associated.
Assuntos
Quirópteros/crescimento & desenvolvimento , Crânio/crescimento & desenvolvimento , Animais , Evolução Biológica , Quirópteros/genética , Desenvolvimento Fetal , Filogenia , Crânio/anatomia & histologia , Especificidade da EspécieRESUMO
Metal elements, ubiquitous in the environment, can cause negative effects in long-lived organisms even after low but prolonged exposure. Insectivorous bats living near metal emission sources can be vulnerable to such contaminants. Although it is known that bats can bioaccumulate metals, little information exists on the effects of metal elements on their physiological status. For example, oxidative status markers are known to vary after detoxification processes and immune reactions. Here, for two consecutive summers, we sampled individuals from a natural population of the insectivorous bat, Myotis daubentonii, inhabiting a site close to a metal emission source. We quantified metals and metalloids (As, Ca, Cd, Co, Cu, Mn, Ni, Pb, Se, Zn) from individual fecal pellets. We measured enzymatic antioxidants (GP, CAT, SOD), total glutathione (tGSH) and ratio between reduced and oxidized glutathione (GSH:GSSG) from their red blood cells together with biometrics, hematocrit and parasite prevalence. In general, metal concentrations in feces of M. daubentonii reflected the exposure to ambient contamination. This was especially evident in the higher concentrations of Cd, Co, Cu and Ni close to a smelter compared to a site with less contaminant exposure. Annual differences were also observed for most elements quantified. Sex-specific differences were observed for calcium and zinc excretion. SOD and CAT enzymatic activities were associated with metal levels (principal components of six metal elements), suggesting early signs of chronic stress in bats. The study also shows promise for the use of non-invasive sampling to assess the metal exposure on an individual basis and metal contamination in the environment.
Assuntos
Antioxidantes/metabolismo , Quirópteros/metabolismo , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Metaloides/análise , Metais Pesados/análise , Estresse Oxidativo/efeitos dos fármacos , Animais , Quirópteros/crescimento & desenvolvimento , Fezes/química , Finlândia , Estações do AnoRESUMO
Assessing population trends and their underlying factors is critical to propose efficient conservation actions. This assessment can be particularly challenging when dealing with highly mobile, shy and nocturnal animals such as flying-foxes. Here we investigated the dynamics of hunted populations of Pteropus ornatus and P. tonganus in the Northern Province of New Caledonia. First, an ethno-ecological survey involving 219 local experts identified 494 flying-fox roosts. Current status was assessed for 379 of them, among which 125 were no longer occupied, representing a loss of 33% over ca. 40 years. Second, species-specific counts conducted at 35 roosts, and a sample of animals killed by hunters, revealed that the endemic species, P. ornatus, was dominant (68.5%). Between 2010 and 2016, 30 roosts were counted annually during the pre-parturition period. Roosts size averaged 1,425 ± 2,151 individuals (N = 180 counts) and showed high among-year variations (roost-specific CV = 37-162%). If we recorded significant inter-annual variation, we did not detect a significant decline over the 7-yr period, although one roost went possibly extinct. Population size of the two species combined was estimated at 338,000-859,000 individuals distributed over ca. 400 roosts in the Northern Province. Flying-foxes are popular game species and constitute traditional food for all communities of New Caledonia. Annual bags derived from a food survey allowed us to estimate harvesting rates at 5-14%. Such a level of harvesting for species with a 'slow' demography, the occurrence of poaching and illegal trade, suggest the current species use might not be sustainable and further investigations are critically needed.
Assuntos
Quirópteros/fisiologia , Densidade Demográfica , Dinâmica Populacional/tendências , Animais , Quirópteros/crescimento & desenvolvimento , Conservação dos Recursos Naturais/tendências , Demografia , Nova Caledônia , Especificidade da EspécieRESUMO
Reproductive seasonality in Neotropical bats has been assessed to the better understand their reproductive behavior. This knowledge is especially important for the control of Desmodus rotundus population as it is a transmitter of rabies virus. Therefore, we aimed to evaluate the functional activity of testis and epididymis of D. rotundus in dry and rainy seasons under a morphological approach. We observed an increase in tubular diameter and epithelial height of the seminiferous tubules during the rainy season. In the latter, additionally, stereological analysis of the testis showed increased proportion of seminiferous epithelium and reduced percentage of lumen. The sperm number in caput/corpus epididymis increased in rainy season, whereas sperm count and transit time were reduced in cauda region. These alterations were probably related to the recovery of epithelium activities after mating season in dry season. Despite altered nuclear and cytoplasm parameters of Leydig cells between seasons, the volume and number of these cells were constant. Moreover, no change in serum testosterone levels, daily sperm production, and apoptotic index were observed, which indicates that the reproductive pattern in D. rotundus does not change between seasons. Our study offers a baseline for the management of vampire bat population as an attempt to control rabies disease.
Assuntos
Quirópteros/fisiologia , Reprodução/fisiologia , Animais , Quirópteros/crescimento & desenvolvimento , Epididimo/patologia , Epididimo/fisiologia , Masculino , Estações do Ano , Espermatozoides/citologia , Espermatozoides/metabolismo , Testículo/patologia , Testículo/fisiologia , Testosterona/sangueRESUMO
Pesquisas com animais em cativeiro são um complemento valioso para estudos de campo e seus resultados podem contribuir significativamente para planos de manejo e conservação in situ e ex situ de espécies. O objetivo do presente trabalho foi a elaboração de um protocolo de manejo para morcegos frugívoros neotropicais que possa ser seguido por profissionais e instituições mantedoras desse grupo. O protocolo foi dividido em três partes: i. morcegos (adaptação, espaço, socialização e marcação), ii. estrutura do recinto (material, temperatura, umidade e iluminação) e iii. alimentação (itens alimentares, regularidade, forma, água e suplementação). Se corretamente aplicado, esse documento poderá facilitar as pesquisas com diferentes espécies de morcegos frugívoros neotropicais, além de proporcionar uma melhor qualidade de vida aos animais cativos.(AU)
Research involving captive animals is a valuable complement to field studies. Its results can significantly contribute to in-situ and ex-situ species management and conservation plans. The purpose of this study was to develop a management protocol for neotropical frugivorous bats that can be followed by professionals and holding institutions. The protocol was divided into three parts: i. bats (adaptation, space, socialization and marking); ii. enclosure structure (material, temperature, humidity and lightning); and iii. feeding (food items, regularity, form, water and supplementation). If properly applied, this document may facilitate research with different species of neotropical frugivorous bats, in addition to providing better quality of life for captive animals.(AU)
Las investigaciones con animales en cautiverio son un valioso complemento para estudios de campo y sus resultados pueden contribuir de manera significativa para planes de manejo y conservación in situ y ex situ de especies. El objetivo de este trabajo fue la elaboración de un protocolo de manejo para murciélagos frugívoros neo tropicales que puedan ser seguidos por profesionales e institucionaes mantenedoras de ese grupo. El protocolo se dividió en tres partes: i. murciélagos (adaptación, espacio, socialización y marcado), ii. estructura del recinto (material, temperatura, humedad e iluminación) y iii. (ítems de alimentos, regularidad, forma, agua y suplementación). Se aplicado correctamente, el documento podrá facilitar las investigaciones con distintas especies de murciélagos frugívoros neo tropicales, además de proporcionar una mejor calidad de vida a los animales cautivos.(AU)
Assuntos
Animais , Socialização , Manejo de Espécimes/métodos , Quirópteros/crescimento & desenvolvimentoRESUMO
Flying foxes have been widely studied as they are well-known reservoirs of infectious agents. Understanding their population dynamics might help to explain seasonal patterns of disease prevalence, and contribute towards the conservation of flying fox populations. Therefore, this study explored the annual variation in the number of deaths in P. lylei. The study was conducted from 2015-2017, at a Buddhist temple in Thailand, which is the roosting site of P. lylei. The average total number of bat deaths in a month significantly varied between times of a year. A peak was observed during March and May, which ranged in the period of birthing and lactating. There were no significant differences in the average total number of bat deaths in a month between sexes or age classes across times of a years.
Assuntos
Quirópteros/crescimento & desenvolvimento , Dinâmica Populacional/estatística & dados numéricos , Estações do Ano , Animais , Feminino , Lactação , Masculino , TailândiaRESUMO
We estimated U.S. and Mexican citizens' willingness to pay (WTP) for protecting habitat for a transborder migratory species, the Mexican free-tailed bat (Tadarida brasiliensis mexicana), using the contingent valuation method. Few contingent valuation surveys have evaluated whether households in one country would pay to protect habitat in another country. This study addresses that gap. In our study, Mexican respondents were asked about their WTP for conservation of Mexican free-tailed bat habitat in Mexico and in the United States. Similarly, U.S. respondents were asked about their WTP for conservation in the United States and in Mexico. U.S. households would pay $30 annually to protect habitat in the United States and $24 annually to protect habitat in Mexico. Mexican households would pay $8 annually to protect habitat in Mexico and $5 annually to protect habitat in the United States. In both countries, these WTP amounts rose significantly for increasing the size of the bat population rather than simply stabilizing the current bat population. The ratio of Mexican household WTP relative to U.S. household WTP is nearly identical to that of Mexican household income relative to U.S. household income. This suggests that the perceived economic benefits received from the bats is similar in Mexico and the United States, and that scaling WTP by relative income in international benefit transfer may be plausible.
Assuntos
Migração Animal , Quirópteros/crescimento & desenvolvimento , Conservação dos Recursos Naturais/economia , Monitoramento Ambiental/economia , Renda , Animais , Quirópteros/fisiologia , Conservação dos Recursos Naturais/métodos , Ecossistema , Monitoramento Ambiental/métodos , Humanos , México , Percepção , Inquéritos e Questionários , Estados UnidosRESUMO
Monitoring flying-foxes is challenging as their extreme mobility produces highly dynamic population processes, considerable logistic difficulty, and variability in estimated population size. We report on methods for inferring population trend for the population of the spectacled flying-fox (Pteropus conspicillatus) in Australia. Monthly monitoring is conducted at all known roost sites across the species' range in the Wet Tropics Region. The proportion of animals in camps varies seasonally and stochastic environmental events appear to be influential. We develop a state-space model that incorporates these processes and enables inference on total population trends and uses early warning analysis to identify the causes of population dynamics. The model suggests that population growth rate is stable in the absence of cyclones, however, cyclones appear to impact on both survival and reproduction. The population recovered after two cyclones but declined after a third. The modelling estimates a population decline over 15 years of c. 75% (mean r = - 0.12yr-1 and belief of negative trend is c. 83%) suggesting that conservation action is warranted. Our work shows that a state-space modelling approach is a significant improvement on inference from raw counts from surveys and demonstrates that this approach is a workable alternative to other methods.
Assuntos
Quirópteros/crescimento & desenvolvimento , Filogeografia , Dinâmica Populacional , Animais , Austrália , Modelos Estatísticos , Análise Espaço-Temporal , Clima TropicalRESUMO
Rensch's rule, stating that sexual size dimorphism (SSD) becomes more evident and male-biased with increasing body size, has been well supported for taxa that exhibit male-biased SSD. Bats, primarily having female-biased SSD, have so far been tested for whether SSD allometry conforms to Rensch's rule in only three studies. However, these studies did not consider phylogeny, and thus the mechanisms underlying SSD variations in bats remain unclear. Thus, the present study reviewed published and original data, including body size, baculum size, and habitat types in 45 bats of the family Rhinolophidae to determine whether horseshoe bats follow Rensch's rule using a phylogenetic comparative framework. We also investigated the potential effect of postcopulatory sexual selection and habitat type on SSD. Our findings indicated that Rensch's rule did not apply to Rhinolophidae, suggesting that SSD did not significantly vary with increasing size. This pattern may be attributable interactions between weak sexual selection to male body size and strong fecundity selection for on female body size. The degree of SSD among horseshoe bats may be attributed to a phylogenetic effect rather than to the intersexual competition for food or to baculum length. Interestingly, we observed that species in open habitats exhibited greater SSD than those in dense forests, suggesting that habitat types may be associated with variations in SSD in horseshoe bats.
Assuntos
Tamanho Corporal , Quirópteros/crescimento & desenvolvimento , Caracteres Sexuais , Animais , Ecossistema , Feminino , Masculino , FilogeniaRESUMO
This study aimed to analyze the reproductive stage, histology and morphometry of the ovary of Dermanura cinerea in an Atlantic Forest fragments in the Biological Reserve of Saltinho, Pernambuco, Brazil. Adult females were captured monthly by mist net, during two consecutive nights from June/2014 to November/2015. The meteorological data were provided by the National Institute of Meteorology and grouped together with the reproductive data, in six periods: period I (June to August/2014), period II (September to November/2014), period III (December/2014 to February/2015), period IV (March to May/2015), period V (June to August/2015) and period VI (September to November/2015). The females were classified according to their reproductive stages in: Inactive, pregnant, lactating and postlactating. Among the 25 females caught, 10 inactive females were selected for the histomorphometric analysis of the ovaries and then they were euthanized. After that, the specimens had their ovaries removed, fixed, processed and included in Paraplast. The organs were cut and stained by Hematoxylin - Eosin and the histological slides produced were submitted to the appropriate optical microscope analysis. Each type of ovarian follicle was estimated according to the histological characteristics evidenced for other mammals. In the morphometric analysis, it was considered: The area of the ovary (measured in square millimeter), Quantification of different types of ovarian follicles (unilaminar and multilaminar primary follicles, antral and matures) and corpus luteum, as well as the area of each by those different follicles (measured in square micrometer) The results indicated that 16 females were inactive, 5 were lactating, 4 were pregnant and no post-lactating. The histological analysis revealed that the ovaries of D. cinerea exhibit characteristics, structures and cellular types similar to other mammals. The morphometric data of the study area were statistically evaluated using the Student's t-test. Therefore, ovarian histomorphometric analysis are very important to infer with greater certainty about the reproduction of a species. Thus, it was observed that females of D. cinerea exhibit two reproductive peaks, that is, they can give birth either at the end of dry periods or from the beginning to the middle of the rainy season. The main feature observed in the ovary of this species, found in the Atlantic Forest area of the state of Pernambuco, is the preparation of the ovarian cortex to ovulate in months of high rainfall throughout the year. Therefore, this species tries to adjust its reproductive period with the variations of the environmental conditions, so that the reproduction might occur during the period more favorable for the maintenance of their offspring.(AU)
Esse estudo objetivou analisar o estágio reprodutivo, histologia e morfometria do ovário de Dermanura cinerea em um fragmento de Mata Atlântica da Reserva Biológica de Saltinho (Pernambuco, Brasil). Foram utilizadas fêmeas adultas capturadas por redes de neblina, de modo que as coletas ocorreram mensalmente, durante duas noites consecutivas de Junho/2014 a Novembro/2015. Os dados meteorológicos foram fornecidos pelo Instituto Nacional de Meteorologia e agrupados, juntamente com os dados reprodutivos, em seis períodos, sendo estes: período I (Junho a agosto/2014), período II (Setembro a novembro/2014), período III (Dezembro/2014 a fevereiro/2015) período IV (Março a maio/2015), período V (Junho a agosto/2015) e período VI (Setembro a novembro/2015). As fêmeas foram classificadas, de acordo com o estágio reprodutivo em: inativas, grávidas, lactantes e pós-lactantes. Das 25 fêmeas capturadas, foram selecionadas, para as análises histomorfométricas dos ovários, 10 fêmeas inativas, as quais foram eutanasiadas. Depois disso, os espécimes tiveram os seus ovários removidos, fixados, processados e inclusos em paraplast. Os cortes foram corados por Hematoxilina - Eosina e as lâminas histológicas produzidas foram submetidas às devidas análises em microscópio óptico. Cada tipo de folículo ovariano foi estimado de acordo com as características histológicas evidenciadas para outros mamíferos. Nas análises morfométricas, considerou-se: a área do ovário (mensurada em milímetro quadrado), quantificação dos diferentes tipos de folículos ovarianos (primários unilaminar e multilaminar, antrais e maduros) e corpo lúteo, bem como foi medida a área de cada um desses diferentes tipos de folículos (mensurada em micrômetro quadrado). Os resultados indicaram a presença de 16 fêmeas inativas, 5 lactantes, 4 grávidas e nenhuma pós-lactante. As análises histológicas destacaram que os ovários de D. cinerea possui características, estruturas e tipos celulares padrões semelhantes ao dos demais mamíferos. Os dados morfométricos da área do ovário foram avaliados estatisticamente por meio do teste t de Student. Assim, as análises histomorfométricas ovariana são de suma importância para inferir com maior segurança sobre a reprodução de uma dada espécie. Portanto, ficou constatado que as fêmeas de D. cinerea apresentam dois picos reprodutivos, isto é, podem parir no final de períodos secos ou do início para metade do período chuvoso. A principal característica observada no ovário dessa espécie, encontrada em área de Mata Atlântica do estado de Pernambuco, foi a preparação do córtex ovariano para ovular em meses de elevados índices pluviométricos ao longo do ano. Logo, essa espécie procura ajustar seu período reprodutivo com as variações das condições ambientais, de forma que a reprodução ocorra em períodos mais favoráveis para manutenção da prole.(AU)
Assuntos
Animais , Feminino , Quirópteros/anatomia & histologia , Quirópteros/crescimento & desenvolvimento , Ovário/anatomia & histologia , Ovário/crescimento & desenvolvimento , BrasilRESUMO
Climate change is a major threat to global biodiversity that will produce a range of new selection pressures. Understanding species responses to climate change requires an interdisciplinary perspective, combining ecological, molecular and environmental approaches. We propose an applied integrated framework to identify populations under threat from climate change based on their extent of exposure, inherent sensitivity due to adaptive and neutral genetic variation and range shift potential. We consider intraspecific vulnerability and population-level responses, an important but often neglected conservation research priority. We demonstrate how this framework can be applied to vertebrates with limited dispersal abilities using empirical data for the bat Plecotus austriacus. We use ecological niche modelling and environmental dissimilarity analysis to locate areas at high risk of exposure to future changes. Combining outlier tests with genotype-environment association analysis, we identify potential climate-adaptive SNPs in our genomic data set and differences in the frequency of adaptive and neutral variation between populations. We assess landscape connectivity and show that changing environmental suitability may limit the future movement of individuals, thus affecting both the ability of populations to shift their distribution to climatically suitable areas and the probability of evolutionary rescue through the spread of adaptive genetic variation among populations. Therefore, a better understanding of movement ecology and landscape connectivity is needed for predicting population persistence under climate change. Our study highlights the importance of incorporating genomic data to determine sensitivity, adaptive potential and range shift potential, instead of relying solely on exposure to guide species vulnerability assessments and conservation planning.
Assuntos
Distribuição Animal , Mudança Climática , Espécies em Perigo de Extinção , Exposição Ambiental , Genética Populacional/métodos , Adaptação Biológica , Animais , Quirópteros/crescimento & desenvolvimento , Filogeografia , Seleção GenéticaRESUMO
Much of the current research on longevity focuses on the aging process within a single species. Several molecular players (e.g. IGF1 and MTOR), pharmacological compounds (e.g. rapamycin and metformin), and dietary approaches (e.g. calorie restriction and methionine restriction) have been shown to be important in regulating and modestly extending lifespan in model organisms. On the other hand, natural lifespan varies much more significantly across species. Within mammals alone, maximum lifespan differs more than 100 fold, but the underlying regulatory mechanisms remain poorly understood. Recent comparative studies are beginning to shed light on the molecular signatures associated with exceptional longevity. These include genome sequencing of microbats, naked mole rat, blind mole rat, bowhead whale and African turquoise killifish, and comparative analyses of gene expression, metabolites, lipids and ions across multiple mammalian species. Together, they point towards several putative strategies for lifespan regulation and cancer resistance, as well as the pathways and metabolites associated with longevity variation. In particular, longevity may be achieved by both lineage-specific adaptations and common mechanisms that apply across the species. Comparing the resulting cross-species molecular signatures with the within-species lifespan extension strategies will improve our understanding of mechanisms of longevity control and provide a starting point for novel and effective interventions.