Flight performance and wing morphology in the bat Carollia perspicillata: biophysical models and energetics.

Studies on functional performance are important to understand the processes responsible for the evolution of diversity. Morphological trait variation within species influences the energetic cost of locomotion and impacts life history traits, with ecological and evolutionary consequences. This study examined wing morphology correlates of flight performance measured by energetic expenditure in the Seba's short-tailed bat, Carollia perspicillata. In the flight experiments, nature caught bats (59 females, 57 males) were allowed to fly for 3 min in a room. After each flight, thermographic images were taken to measure body temperature, and biophysical models were used to calculate sensible heat loss as a measure of energetic expenditure. Wing morphological traits were measured for each individual and associated with heat loss and power required to fly on performance surfaces. Wing morphological traits explained 7-10% of flight energetic cost, and morphologies with the best performance would save the energy equivalent to 9-30% of total daily requirements. The optimal performance areas within the C. perspicillata morphospace were consistent with predicted selection trends from the literature. A trade-off between demands for flight speed and maneuverability was observed. Wing loading and camber presented sexual dimorphism. These morphological differences are likely associated with more economical but less maneuverable flight in females, leading them to fly more often in open areas along the forest edge. Our findings demonstrate how small scale changes in wing morphology can affect life history strategies and fitness.

Morphological variation of the brachial plexus in four phyllostomid bat species (Chiroptera, Phyllostomidae).

Despite the remarkable morphological modifications that occurred in the thoracic limbs of bats, information about the brachial plexus in this group is still scarce. The present study aimed to describe the origin, structure, and distribution of these peripheral nerves in four Phyllostomidae species. Both antimeres of six Artibeus lituratus, five Desmodus rotundus, seven Glossophaga soricina, and five Phyllostomus hastatus-all adult males from the Adriano Lúcio Peracchi Collection (UFRRJ)-were dissected. After complete exposure of the structure, we found that the brachial plexus of D. rotundus and P. hastatus is formed by the same roots (C5-T1), whereas the fourth cervical spinal nerve and the second thoracic spinal nerve are present in G. soricina (C4-T1) and A. lituratus (C5-T2), respectively. There was intraspecific variation and asymmetry in the origin of the structure and the combinations of nerve segments forming terminal branches. The distribution to the target muscles and patagium, however, was not subject to significant variation in our sample. Data presented here support the presence of two prevailing conditions in distribution of nerves to the bat muscles, and the innervation of the membranes seems to be explained by embryogenesis. Although the brachial plexus in phyllostomid bats is similar to that of other terrestrial Laurasiatheria, aspects identified in these bats, apparently unique to Chiroptera, may be related to anatomical changes in the thoracic limbs functionally linked to flight.

Comparative morphology and scaling of the femur in yangochiropteran bats.

Better known by their remarkable forelimb morphology, bats are also unique among mammals with respect to their hindlimbs. Their legs are rotated through 180°, generally reduced in size, and in some extant taxa particular bones (e.g. fibula) can even be absent. The femur is the main leg bone, but to date few bat studies have considered its morphology in detail, none in a wide-scale comparative study. Yangochiroptera is the largest bat taxon, spans nearly three orders of magnitude in body mass, and is highly diverse both in ecology and behavior, representing a good model for comparative analyses. Here, we describe the anatomy of the femur in a large sample of yangochiropteran bats (125 species, 70 genera, and 12 families), and explore major trends of morphological variation and scaling patterns in this bone. We used 13 categorical characters in the anatomical description and five linear dimensions in the quantitative analyses. Based on the categorical data, each family studied here was diagnosed, and those from the Neotropical region were included in an identification key. From the phylogenetic principal component analysis (pPCA) we showed that, in addition to size, major axes of variation in bat femur are related to robusticity and head morphology, features that are clearly distinct among some families. We also generated a phylomorphospace based on pPCA scores, highlighting convergences in femur shape. Molossidae, Mystacinidae, and Desmodontinae were grouped based on their greater robusticity, a pattern that was also recovered from categorical data. In these families, we found anatomical features (e.g. presence of tubercles and posterior ridges on the greater trochanter, long or medially/distally displaced lateral ridges on the shaft) that are well-known from their functional link with quadrupedal locomotion. Using phylogenetic regressions, we found out that compared with body mass, femur length scaled with negative allometry, as expected, but that femur width scaled isometrically, counter to expectations. As a result, robusticity index (the ratio of width to length), scaled with positive allometry - larger bats tended to have more robust hindlimbs. At species level, our most remarkable finding was related to Myotis simus, which presented the most robust femur (for its size) among yangochiropterans. Our results reinforce the informative potential of the chiropteran femur from both taxonomic and functional perspectives. Furthermore, the allometric trends seen in this bone may help understand the strategies adopted by flying vertebrates to deal with the high energetic cost of flight and, at the same time, evolve diversified foraging behaviors.

Small mammals (Chiroptera, Didelphimorphia, and Rodentia) from Jaíba, middle Rio São Francisco, northern Minas Gerais State, Brazil / Pequenos mamíferos (Chiroptera, Didelphimorphia, and Rodentia) de Jaíba, médio Rio São Francisco, norte do estado de Minas Gerais, Brasil

We report the results of small mammals inventories conducted in the region of Jaíba, northern Minas Gerais state, southeastern Brazil, from 1990 to 1995. This region is located in the southern limit of the Caatinga biome, and harbors a unique set of natural ecosystems and extensive agricultural areas. With a total effort of 2964 trap-nights and 44 net sessions, we captured 893 small mammals from 46 species, including four marsupials, 13 rodents, and 29 bats. We report on species that are endemic to the Caatinga (Wiedomys pyrrhorhinos and Xeronycteris vieirai), and species that are new to the mammal fauna of the state of Minas Gerais (Tonatia saurophila, X. vieirai, and Myotis lavali). We also provide the first valid voucher-supported record of Micronycteris sanborni from southeastern Brazil, and extend the known range of X. vieirai 800 km southward. All bats highlighted here as endemic or representing new records were associated to limestone outcrops, suggesting that preservation of this kind of habitat may be particularly relevant to the conservation of these mammals.

Reportamos os resultados de inventários de pequenos mamíferos conduzidos na região de Jaíba, norte de Minas Gerais, sudeste do Brasil, entre 1990 e 1995. Essa região está localizada no limite sul do bioma Caatinga, e abriga um conjunto único de ecossistemas naturais e extensas áreas cultivadas. Com um esforço total de 2964 armadilhas-noite e 44 sessões de captura com redes de neblina, nós capturamos 893 pequenos mamíferos, que permitiram a identificação de 46 espécies, incluindo quatro marsupiais, 13 roedores e 29 morcegos. Nós reportamos espécies endêmicas da Caatinga (Wiedomys pyrrhorhinos e Xeronycteris vieirai) e espécies que são novas para a fauna de mamíferos de Minas Gerais (Tonatia saurophila, X. vieirai e Myotis lavali). Nós também fornecemos o primeiro registro válido, com material testemunho, de Micronycteris sanborni para o sudeste do Brasil, e estendemos a distribuição geográfica conhecida de X. vieirai em 800 km na direção sul. Todos os morcegos destacados aqui como endêmicos ou representando novos registros estiveram associados a afloramentos de calcário, sugerindo que a preservação deste tipo de hábitat pode ser particularmente relevante para conservação desses mamíferos.