RESUMO

One of the consequences of anthropogenic climate change is an increase in the frequency and intensity of extreme weather events. These events have caused mass mortality of different species of wildlife, including bats. In this study, we exposed two species of neotropical nectar-feeding bats that live in contrasting environmental conditions (A. geoffroyi and L. yerbabuenae) to extreme high and low temperatures while offering them diets with different energy content. This experimental approach allowed us to determine their thermal and behavioral responses, and to identify environmental conditions that impose high physiologic costs to these species. To determine how bats' responded, we monitored both changes in their body masses and skin temperatures. Both bat species responded differently, with L. yerbabuenae spending more time in normothermia at high temperatures than A. geoffroyi. While both species presented torpor, they used it differently. Torpor allowed A. geoffroyi to maintain and increase body mass at intermediate and low ambient temperatures. At the same time, L. yerbabuenae used torpor only when facing cold ambient temperatures and low-quality food. Understanding the mechanisms that allow species to face changes in their environment is essential given the current climate trends and the fact that the loss of these species could have significant negative consequences in tropical and subtropical ecosystems.

Assuntos

RESUMO

The genus Agave sensu lato contains ca. 211 described species, many of which are considered keystone species because of their ecological dominance and the quantity of resources they provide with their massive, nectar-rich inflorescences. The large diversity of Agave species has been hypothesized as being related to their reproductive strategy (predominantly monocarpic) and diverse pollinators (e.g., bats, hummingbirds, hawkmoths). In particular, Agave species provide resources that a few genera of nectar feeding bats from the subfamily Glosophaginae are dependent upon. To explore a possible coevolutionary relationship between Agave and the bat species that pollinate them, we calibrated molecular phylogenies of both groups and looked for a correlation in their dates of divergence. One coding and two non-coding regions of the chloroplast genome were sequenced from 49 species of the Agavoideae (Asparagaceae), and the mitochondrial gene Cyt-b and nuclear coding gene RAG2 were either sequenced or obtained from gene bank for 120 Phyllostomid bats. Results from the analyses indicate that Agave sensu lato is a young genus (estimated crown age 2.7-8.5/stem age 4.6-12.3 Ma), with an increasing diversification rate, and the highest speciation rate among Agavoideae's clades. The origin of the Glossophaginae bats (stem age 20.3-23.5 Ma) occurred prior to the stem age of Agave sensu lato, while the origin of the current pollinators of Agave species, members of the genera Glossophaga, Leptonycteris, Anoura, Choeronyscus, Musonycteris and Choeronycteris, was estimated to be around 6.3-16.2 Ma, overlapping with the stem age of Agave sensu lato, supporting the hypothesis of diffuse coevolution.

Assuntos

RESUMO

Abstract: We provide the first report of the frequency of leucism for a species of Neotropical bat. Leucism is an anomaly of the skin pigmentation of an animal that manifests itself as the total or partial loss of the natural color of the species, and can affect part of or the entire body. During a study involving capture and marking individuals of a population of A. geoffroyi residing in a cave in the Brazilian state of Minas Gerais, seven individuals with some degree of depigmentation were recorded out of 616 individuals marked, for a frequency of 1.1%. Since leucism is due to recessive gene expression, these findings may indicate that the population is isolated and possesses a high level of endogamy. Factors that may be responsible for this condition in the studied population remain unknown.

Resumo: Relatamos aqui o primeiro registro de frequência de leucismo em uma espécie de morcego Neotropical. Leucismo é uma anomalia na pigmentação da pele dos animais que consiste na perda total ou parcial da cor natural da espécie, podendo acometer partes ou todo o corpo do animal. Em um estudo de captura e marcação de indivíduos de uma população de A. geoffroyi abrigada em uma caverna localizada no estado de Minas Gerais, foram registrados sete indivíduos com algum grau de despigmentação dentre 616 indivíduos marcados, representando 1.1% da população. Leucismo é um tipo de anomalia de coloração de expressão gênica recessiva, portanto, esse resultado pode indicar isolamento da população e nível elevado de endogamia. Fatores que podem levar à esta condição nessa população são desconhecidos.

RESUMO

Many insects use nectar as their principal diet and have mouthparts specialized in nectarivory, whereas most nectar-feeding vertebrates are opportunistic users of floral resources and only a few species show distinct morphological specializations. Specialized nectar-feeding bats extract nectar from flowers using elongated tongues that correspond to two vastly different morphologies: Most species have tongues with hair-like papillae, whereas one group has almost hairless tongues that show distinct lateral grooves. Recent molecular data indicate a convergent evolution of groove- and hair-tongued bat clades into the nectar-feeding niche. Using high-speed video recordings on experimental feeders, we show distinctly divergent nectar-feeding behavior in clades. Grooved tongues are held in contact with nectar for the entire duration of visit as nectar is pumped into the mouths of hovering bats, whereas hairy tongues are used in conventional sinusoidal lapping movements. Bats with grooved tongues use a specific fluid uptake mechanism not known from any other mammal. Nectar rises in semiopen lateral grooves, probably driven by a combination of tongue deformation and capillary action. Extraction efficiency declined for both tongue types with a similar slope toward deeper nectar levels. Our results highlight a novel drinking mechanism in mammals and raise further questions on fluid mechanics and ecological niche partitioning.

RESUMO

Glossophaga soricina soricina (Pallas, 1766) plays an important role in the ecosystems where it is found, taking part in the pollination of hundreds of plant species. Here, we statistically compared 12 external characters of 169 specimens collected in three Brazilian biomes: 82 in the Pantanal (Mato Grosso), 45 in the Atlantic Forest (Ilhéus, Bahia) and 42 in the Caatinga (Chapada Diamantina, Bahia). Each character was analyzed by descriptive and inferential statistics. The t-test didn't detect any differences between males and females of each population. The ANOVA with a posteriori Tukey test showed significant results for all traits (Forearm length, Calcar length, Body length, Tail length, Hindfoot length, Ear length, Tragus length, Thumb length, Noseleaf length, Noseleaf width and Horseshoe width) except for Tibia length. The discriminant analysis showed distinct clusters representing the populations of each biome. The tests demonstrated that the three populations are significantly different from one another and that the specimens of the population from the Caatinga, on average, are larger than those from the Pantanal, which are larger than those from the Atlantic Forest, confirming the possible existence of intra-specific geographic variation.

RESUMO

Glossophaga soricina soricina (Pallas, 1766) plays an important role in the ecosystems where it is found, taking part in the pollination of hundreds of plant species. Here, we statistically compared 12 external characters of 169 specimens collected in three Brazilian biomes: 82 in the Pantanal (Mato Grosso), 45 in the Atlantic Forest (Ilhéus, Bahia) and 42 in the Caatinga (Chapada Diamantina, Bahia). Each character was analyzed by descriptive and inferential statistics. The t-test didn't detect any differences between males and females of each population. The ANOVA with a posteriori Tukey test showed significant results for all traits (Forearm length, Calcar length, Body length, Tail length, Hindfoot length, Ear length, Tragus length, Thumb length, Noseleaf length, Noseleaf width and Horseshoe width) except for Tibia length. The discriminant analysis showed distinct clusters representing the populations of each biome. The tests demonstrated that the three populations are significantly different from one another and that the specimens of the population from the Caatinga, on average, are larger than those from the Pantanal, which are larger than those from the Atlantic Forest, confirming the possible existence of intra-specific geographic variation.

RESUMO

Glossophaga soricina soricina (Pallas, 1766) plays an important role in the ecosystems where it is found, taking part in the pollination of hundreds of plant species. Here, we statistically compared 12 external characters of 169 specimens collected in three Brazilian biomes: 82 in the Pantanal (Mato Grosso), 45 in the Atlantic Forest (Ilhéus, Bahia) and 42 in the Caatinga (Chapada Diamantina, Bahia). Each character was analyzed by descriptive and inferential statistics. The t-test didn't detect any differences between males and females of each population. The ANOVA with a posteriori Tukey test showed significant results for all traits (Forearm length, Calcar length, Body length, Tail length, Hindfoot length, Ear length, Tragus length, Thumb length, Noseleaf length, Noseleaf width and Horseshoe width) except for Tibia length. The discriminant analysis showed distinct clusters representing the populations of each biome. The tests demonstrated that the three populations are significantly different from one another and that the specimens of the population from the Caatinga, on average, are larger than those from the Pantanal, which are larger than those from the Atlantic Forest, confirming the possible existence of intra-specific geographic variation.

RESUMO

During an inventory fieldwork carried out at Usina Salgado property in the county of Ipojuca, Pernambuco, Brazil, we captured a Lionycteris spurrelli specimen in a forest fragment known as Mata do Mingú (8º 31' 29" S and 35º 03' 26" W). This marks the first occurrence for the northeast region and therefore, the first record for the state of Pernambuco, widening its distribution area within Atlantic Forest. The extension of the occurrence area points out this record as being the oriental limit for the species.

Durante um trabalho de campo realizado nas propriedades da Usina Salgado, no município de Ipojuca, Pernambuco, foi capturado um indivíduo da espécie Lionycteris spurrelli, no fragmento denominado Mata do Mingú (8º 31' 29" S e 35º 03' 26" W). O fato registra a primeira ocorrência para a região Nordeste e conseqüentemente o primeiro registro para o estado de Pernambuco, ampliando a área de distribuição do morcego na Floresta Atlântica. A extensão da área de ocorrência aponta este registro como o limite oriental para a espécie.

Assuntos

RESUMO

The reproductive patterns and feeding habits of three sympatric nectarivorous bats, Glossophaga soricina, Anoura caudifera, and A. geoffroyi were studied in the Pousada das Araras Natural Reserve, located in Central Brazil. The bats were captured with mist nets from August 2000 to July 2001. Reproductive condition was determined by external analyses of the specimens and feeding habits from fecal samples. Glossophaga soricina was the most abundant species (65%), followed by A. geoffroyi (30%) and A. caudifera (5%). Significant differences were observed in the sex-ratio of the two more abundant species. Anoura geoffroyi showed a monoestrous pattern; its reproductive peaks occurred between the end of the dry season and the beginning of the rain season. A seasonal bimodal pattern was recorded for G. soricina, with pregnant specimens showing one peak observed in the dry season and another in the middle of the rainy season. The reproductive pattern of A. caudifera could not be satisfactorily defined because of the small sample size. However, this species apparently has a reproductive cycle similar to that of G. soricina. The patterns observed in this study seem to be related with the climate in the Brazilian savanna (Cerrado), with two well-defined seasons (dry and wet). By adjusting the parturition close to or in the rain season the three species could be favoring a greates survival rate for the offspring, since the critical lactation period would then occur in a time of maximum food availability. The three bat species showed a generalist diet, consuming fruits, pollen-nectar, and arthropods. Significant differences were observed in the diet of G. soricina: fruits and arthropods predominated in the dry season and pulp (fruits) in the rainy season. Males and females of this species ate the same items in similar proportions. Although A. geoffroyi has not showed a preference for a specific item, consumption of fruits and arthropods was generally greater than that of pollen.

Os padrões reprodutivos e alimentares de três espécies simpátricas de morcegos nectarívoros, Glossophaga soricina, Anoura caudifera e A. geoffroyi, foram estudados na Reserva Natural Pousada das Araras no Brasil Central. Os morcegos foram capturados mensalmente durante um ano (agosto de 2000 a julho de 2001), com redes de neblina. Os estágios reprodutivos foram inferidos por intermédio de análises externas dos animais e a dieta, por intermédio da coleta de fezes dos animais. Glossophaga soricina foi a espécie mais abundante (65%), seguida por A. geoffroyi (30%) e A. caudifera (5%). Foram observadas diferenças significativas na razão sexual das duas espécies mais abundantes. Anoura geoffroyi apresentou um padrão monoéstrico de reprodução com o pico reprodutivo ocorrendo entre o final da estação seca e o início da estação chuvosa. Um padrão poliéstrico bimodal foi identificado para G. soricina, com um pico de fêmeas grávidas observado no final da estação seca e outro na metade da estação chuvosa. O período reprodutivo de A. caudifera não pôde ser definido satisfatoriamente em função do pequeno tamanho da amostra. Contudo, essa espécie apresentou aparentemente um ciclo similar a G. soricina. Os padrões observados neste estudo parecem estar relacionados à sazonalidade climática do Cerrado, que apresenta duas estações bem definidas (seca e chuvosa). As três espécies, ajustando os picos de nascimentos para a estação chuvosa, poderiam garantir maior sucesso de sobrevivência dos filhotes, visto que o período crítico da lactação estaria ocorrendo numa época de máxima oferta de alimentos. Os morcegos estudados apresentaram dieta generalista, consumindo frutos, pólen-néctar e artrópodes. Ocorreu diferença significativa na dieta de G. soricina, em que frutos e artrópodes foram os itens predominantes na estação seca, enquanto frutos (polpa) predominou na estação chuvosa. Machos e fêmeas dessa espécie comeram os mesmos itens numa proporção semelhante. Embora A. geoffroyi não tenha tido preferência por determinado item específico, frutos e artrópodes foram mais consumidos do que pólen.

RESUMO

The reproductive patterns and feeding habits of three sympatric nectarivorous bats, Glossophaga soricina, Anoura caudifera, and A. geoffroyi were studied in the Pousada das Araras Natural Reserve, located in Central Brazil. The bats were captured with mist nets from August 2000 to July 2001. Reproductive condition was determined by external analyses of the specimens and feeding habits from fecal samples. Glossophaga soricina was the most abundant species (65%), followed by A. geoffroyi (30%) and A. caudifera (5%). Significant differences were observed in the sex-ratio of the two more abundant species. Anoura geoffroyi showed a monoestrous pattern; its reproductive peaks occurred between the end of the dry season and the beginning of the rain season. A seasonal bimodal pattern was recorded for G. soricina, with pregnant specimens showing one peak observed in the dry season and another in the middle of the rainy season. The reproductive pattern of A. caudifera could not be satisfactorily defined because of the small sample size. However, this species apparently has a reproductive cycle similar to that of G. soricina. The patterns observed in this study seem to be related with the climate in the Brazilian savanna (Cerrado), with two well-defined seasons (dry and wet). By adjusting the parturition close to or in the rain season the three species could be favoring a greates survival rate for the offspring, since the critical lactation period would then occur in a time of maximum food availability. The three bat species showed a generalist diet, consuming fruits, pollen-nectar, and arthropods. Significant differences were observed in the diet of G. soricina: fruits and arthropods predominated in the dry season and pulp (fruits) in the rainy season. Males and females of this species ate the same items in similar proportions. Although A. geoffroyi has not showed a preference for a specific item, consumption of fruits and arthropods was generally greater than that of pollen.

Os padrões reprodutivos e alimentares de três espécies simpátricas de morcegos nectarívoros, Glossophaga soricina, Anoura caudifera e A. geoffroyi, foram estudados na Reserva Natural Pousada das Araras no Brasil Central. Os morcegos foram capturados mensalmente durante um ano (agosto de 2000 a julho de 2001), com redes de neblina. Os estágios reprodutivos foram inferidos por intermédio de análises externas dos animais e a dieta, por intermédio da coleta de fezes dos animais. Glossophaga soricina foi a espécie mais abundante (65%), seguida por A. geoffroyi (30%) e A. caudifera (5%). Foram observadas diferenças significativas na razão sexual das duas espécies mais abundantes. Anoura geoffroyi apresentou um padrão monoéstrico de reprodução com o pico reprodutivo ocorrendo entre o final da estação seca e o início da estação chuvosa. Um padrão poliéstrico bimodal foi identificado para G. soricina, com um pico de fêmeas grávidas observado no final da estação seca e outro na metade da estação chuvosa. O período reprodutivo de A. caudifera não pôde ser definido satisfatoriamente em função do pequeno tamanho da amostra. Contudo, essa espécie apresentou aparentemente um ciclo similar a G. soricina. Os padrões observados neste estudo parecem estar relacionados à sazonalidade climática do Cerrado, que apresenta duas estações bem definidas (seca e chuvosa). As três espécies, ajustando os picos de nascimentos para a estação chuvosa, poderiam garantir maior sucesso de sobrevivência dos filhotes, visto que o período crítico da lactação estaria ocorrendo numa época de máxima oferta de alimentos. Os morcegos estudados apresentaram dieta generalista, consumindo frutos, pólen-néctar e artrópodes. Ocorreu diferença significativa na dieta de G. soricina, em que frutos e artrópodes foram os itens predominantes na estação seca, enquanto frutos (polpa) predominou na estação chuvosa. Machos e fêmeas dessa espécie comeram os mesmos itens numa proporção semelhante. Embora A. geoffroyi não tenha tido preferência por determinado item específico, frutos e artrópodes foram mais consumidos do que pólen.