Condiciones microclimáticas, hábitos de percha y especies asociadas a los refugios de Natalus Stramineus en México

Natalus stramineus is a cave-dwelling bat broadly spread in Mexico but with scarce information about its natural history. In this work, we reported the associated bat species and roosting sites of N. stramineus in Mexico. Also we observed roosting habits and recorded monthly air temperature and relative humidity throughout one year in a roost of this bat, located in the state of Colima, Mexico. It has been found in 108 roosting sites most of which are caves and mines. These roosts were located in a wide range of elevations, vegetation and climates, however most were located below 400 m asl, in tropical deciduous forest and hot-subhumid conditions. We were unable to find this species in some previously recorded caves. In El Salitre Cave, temperature and relative humidity in their roosting sites were stable throughout the year. The former variable fluctuates from 25.8 to 26.9°C and the latter variable from 92.1 to 100%. Individuals of N. stramineus usually hang in the lower parts of walls and rocky ceilings, occupying cavities and crevices occasionally. They hang individually without contact to each other, keeping a distance of 5-50 cm between themselves. Forty-five bat species have been found associated with this natalid, but more frequently Pteronotus parnellii, Mormoops megalophylla, Glossophaga soricina y Desmodus rotundus. This bat prefers to occupy warm and humid parts of the roosts, because these conditions are ideal to conserve the body heat and to maintain their wings in good conditions. Its great tendency to be associated with mormopids and some phyllostomids is explained partly by their similar microclimatic requirements in their refuges, as well as by the thermal benefits associated with clustering in colonies. N. stramineus depends heavily on hot caves for their survivorship and occupies mines with similar microclimatic conditions in an opportunistic way.Natalus stramineus es un murciélago cavernícola ampliamente extendido en México del que poco se sabe sobre su historia natural. En el presente trabajo, se reportan los refugios y las especies asociadas a este murciélago en México. Además se reporta la variación mensual de la temperatura ambiente y humedad relativa en una cueva donde se alberga, localizada en Colima, México, donde también se observaron sus hábitos de percha. Este murciélago ha sido encontrado en 108 refugios que en su gran mayoría son cuevas y minas, los cuales se localizaron en un amplio intervalo de altitud, tipos de vegetación y climas; sin embargo, la mayoría se encuentran a alturas menores a los 400 msnm, en selva baja caducifolia y con clima cálido-subhúmedo. En algunos sitios donde se había reportado su presencia no pudo ser encontrado durante los muestreos realizados. En la cueva El Salitre, la temperatura y humedad en sus sitios de percha permanecieron estables a lo largo del año. La primera variable osciló de 25.8 a 26.9°C y la segunda de 92.1 a 100%. Los individuos usualmente se cuelgan en las partes bajas de las paredes y en techos inclinados, utilizando también cavidades de disolución y ocasionalmente grietas. Perchan individualmente sin estar en contacto directo uno con otro, manteniendo una distancia de 5-50 cm. Se registraron 45 especies de murciélagos asociadas a N. stramineus, pero con mayor frecuencia a Pteronotus parnellii, Mormoops megalophylla, Glossophaga soricina y Desmodus rotundus. N. stramineus prefiere ocupar secciones cálidas y muy húmedas de los refugios, siendo estas condiciones ideales para conservar el calor corporal y mantener en buen estado sus alas. Su gran tendencia a asociarse con mormópidos y algunos filostómidos se explica, en parte, por requerir condiciones microclimáticas similares en sus refugios, así como por los beneficios termoregulatorios que tiene el agrupamiento en colonias. Este murciélago depende mucho de cuevas de calor para su supervivencia y ocupa de manera oportunista minas con características microclimáticas similares

Condiciones microclimáticas, hábitos de percha y especies asociadas a los refugios de Natalus Stramineus en México

Natalus stramineus is a cave-dwelling bat broadly spread in Mexico but with scarce information about its natural history. In this work, we reported the associated bat species and roosting sites of N. stramineus in Mexico. Also we observed roosting habits and recorded monthly air temperature and relative humidity throughout one year in a roost of this bat, located in the state of Colima, Mexico. It has been found in 108 roosting sites most of which are caves and mines. These roosts were located in a wide range of elevations, vegetation and climates, however most were located below 400 m asl, in tropical deciduous forest and hot-subhumid conditions. We were unable to find this species in some previously recorded caves. In El Salitre Cave, temperature and relative humidity in their roosting sites were stable throughout the year. The former variable fluctuates from 25.8 to 26.9°C and the latter variable from 92.1 to 100%. Individuals of N. stramineus usually hang in the lower parts of walls and rocky ceilings, occupying cavities and crevices occasionally. They hang individually without contact to each other, keeping a distance of 5-50 cm between themselves. Forty-five bat species have been found associated with this natalid, but more frequently Pteronotus parnellii, Mormoops megalophylla, Glossophaga soricina y Desmodus rotundus. This bat prefers to occupy warm and humid parts of the roosts, because these conditions are ideal to conserve the body heat and to maintain their wings in good conditions. Its great tendency to be associated with mormopids and some phyllostomids is explained partly by their similar microclimatic requirements in their refuges, as well as by the thermal benefits associated with clustering in colonies. N. stramineus depends heavily on hot caves for their survivorship and occupies mines with similar microclimatic conditions in an opportunistic way.Natalus stramineus es un murciélago cavernícola ampliamente extendido en México del que poco se sabe sobre su historia natural. En el presente trabajo, se reportan los refugios y las especies asociadas a este murciélago en México. Además se reporta la variación mensual de la temperatura ambiente y humedad relativa en una cueva donde se alberga, localizada en Colima, México, donde también se observaron sus hábitos de percha. Este murciélago ha sido encontrado en 108 refugios que en su gran mayoría son cuevas y minas, los cuales se localizaron en un amplio intervalo de altitud, tipos de vegetación y climas; sin embargo, la mayoría se encuentran a alturas menores a los 400 msnm, en selva baja caducifolia y con clima cálido-subhúmedo. En algunos sitios donde se había reportado su presencia no pudo ser encontrado durante los muestreos realizados. En la cueva El Salitre, la temperatura y humedad en sus sitios de percha permanecieron estables a lo largo del año. La primera variable osciló de 25.8 a 26.9°C y la segunda de 92.1 a 100%. Los individuos usualmente se cuelgan en las partes bajas de las paredes y en techos inclinados, utilizando también cavidades de disolución y ocasionalmente grietas. Perchan individualmente sin estar en contacto directo uno con otro, manteniendo una distancia de 5-50 cm. Se registraron 45 especies de murciélagos asociadas a N. stramineus, pero con mayor frecuencia a Pteronotus parnellii, Mormoops megalophylla, Glossophaga soricina y Desmodus rotundus. N. stramineus prefiere ocupar secciones cálidas y muy húmedas de los refugios, siendo estas condiciones ideales para conservar el calor corporal y mantener en buen estado sus alas. Su gran tendencia a asociarse con mormópidos y algunos filostómidos se explica, en parte, por requerir condiciones microclimáticas similares en sus refugios, así como por los beneficios termoregulatorios que tiene el agrupamiento en colonias. Este murciélago depende mucho de cuevas de calor para su supervivencia y ocupa de manera oportunista minas con características microclimáticas similares

Diferencias en algunos parámetros demográficos de oryzomys chapmani (rodentia: muridae) asociadas a tres estados sucesionales de bosque mesófilo de montaña en Oaxaca, México

We studied the differences among apparent survival and capture probabilities, sex ratio, and population size of the Mexican endemic rodent Oryzomys chapmani associated to a chronosequence integrated by three succesional stages of cloud forest. The study was made at the Sierra Norte de Oaxaca region, and the regeneration times of the forests studied were 15 (Young), 40 (Medium), and 100 (Mature) years. 227 adult specimens were capture, marked, and released by 14 months. The apparent survival probabilities were similar in the Young and Medium forests, without fluctuations across time, whereas in the Mature Forest the dry season shows higher value. The capture probabilities did not show variation across time in the Young and Medium forests, but in the Mature Forest showed difference, with higher value in the rainy season. The Young Forest shows a significant excess of males, whereas the Medium and Mature Forest do not differ significantly from the 1:1 sex ratio. The population size was from 42 individuals by hectares in the rainy season to 302 in the dry season, both in the Mature Forest.Se estudiaron las diferencias en probabilidades de supervivencia y captura, proporción de sexos y tamaño poblacional en el roedor endémico de México Oryzomys chapmani asociadas a una cronosecuencia constituida por tres estados sucesionales de bosque mesófilo de montaña. El estudio se realizó en la región Sierra Norte de Oaxaca y los tiempos de regeneración de los fragmentos de bosque estudiados fueron 15 (Joven), 40 (Intermedio) y 100 (maduro) años. Se capturaron, marcaron y liberaron 277 ejemplares adultos durante 14 meses. Las probabilidades de supervivencia fueron similares en los bosques Joven e Intermedio, sin fluctuaciones a través del tiempo, mientras que en el Maduro se observó un valor más alto en la temporada seca. Las probabilidades de captura no mostraron variación a través del tiempo en los estados Joven e Intermedio, pero en el Maduro difirieron entre temporadas, con valores más altos en la de lluvias. Los estados Intermedio y Maduro muestran una proporción 1:1 entre sexos, mientras que el Joven se observó un predominio significativo de machos. El tamaño poblacional vario de 42 individuos por hectárea en la temporada de lluvias a 309 en la seca, ambos en el Bosque Maduro

ANÁLISIS ESTRUCTURAL DEL GEN MITOCONDRIAL CITOCROMO B Y DE LA REGIÓN CONTROL DE CYNOMYS MEXICANUS Y SPERMOPHILUS SPILOSOMA (RODENTIA: SCIURIDAE)

The nucleotide sequences of the cytochrome b gene and of the control region are described for Cynomys mexicanus and Spermophilus spilosoma. The cytochrome b gene was characterized by the presence of eight non-synonymous substitutions at the inter-generic level, presented mainly in the transmembrane zone (87%). The control region was characterized by the presence of the conserved blocks, ETAS1 and CSB1; by the absence of repetitive sequences and by the conserved blocks, ETAS2, CSB2 and CSB3. Most of the inter-generic variation (47.9%) was observed in the ETAS domain. The structure of the control region was similar to that of phylogenetic related species.The nucleotide sequences of the cytochrome b gene and of the control region are described for Cynomys mexicanus and Spermophilus spilosoma. The cytochrome b gene was characterized by the presence of eight non-synonymous substitutions at the inter-generic level, presented mainly in the transmembrane zone (87%). The control region was characterized by the presence of the conserved blocks, ETAS1 and CSB1; by the absence of repetitive sequences and by the conserved blocks, ETAS2, CSB2 and CSB3. Most of the inter-generic variation (47.9%) was observed in the ETAS domain. The structure of the control region was similar to that of phylogenetic related species

Evolutionary scenarios associated with the Pteronotus parnellii cryptic species-complex (Chiroptera: Mormoopidae).

One of the major challenges to understanding the evolution of Neotropical bats concerns our capacity to successfully scrutinize phylogenetic patterns associated with cases of cryptic species complexes. In this study Pteronotus parnellii is examined as a selected example of a known lineage of mormoopid bat that potentially contains several cryptic species. A samples of 452 individuals from 83 different localities, essentially covering its entire mainland distribution, was evaluated using two genetic markers: COI (mitochondrial) and DBY (nuclear) genes. The findings of this study strongly support the hypothesis of high genetic variability and identify at least six lineages within P. parnellii, some of which appear to be cryptic species.Peer reviewe

Genetic Introgression and Morphological Variation in Naked-Back Bats (Chiroptera: Mormoopidae: Pteronotus Species) along Their Contact Zone in Central America

Two sibling bare-backed bat species (Pteronotus fulvus and P. gymnonotus) have been traditionally differentiated by their size. However, intermediate specimens between the two species have been found in sympatric populations along southern Mexico and it has been suggested that they may be the outcome of a hybridization process between the two species. We used one mitochondrial (COI), three nuclear markers (PRKCL, STAT5A and RAG2) and 13 microsatellites to explore the evolutionary relationships between these two species and elucidate whether the intermediate morphotypes correspond to hybrid individuals. These markers have been analyzed in sympatric and allopatric populations of the two species plus the closely related species Pteronotus davyi. We confirmed the species-level differentiation of the three lineages (P. fulvus, P. davyi and P. gymnonotus), but the phylogenetic hypotheses suggested by the nuclear and mitochondrial markers were discordant. We confirm that the discordance between markers is due to genetic introgression through the mitochondrial capture of P. fulvus in P. gymnonotus populations. Such introgression was found in all P. gymnonotus specimens across its sympatric distribution range (Mexico to Costa Rica) and is related to expansion/retraction species distribution pulses associated with changes in forest distribution during the Quaternary climate cycles. Microsatellite analyses showed contemporary genetic contact between the two sympatric species and 3.0% of the samples studied were identified as hybrids. In conclusion, we found a historical and asymmetric genetic introgression (through mitochondrial capture) of P. fulvus into P. gymnonotus in Mexico and Central America and a limited contemporary gene exchange between the two species. However, no relationship was found between hybridization and the intermediate-sized specimens from southern Mexico, which might likely result from a clinal variation with latitude. These results confirm the need for caution when using forearm size to identify these species in the field and when differentiating them in the laboratory based on mitochondrial DNA alone

Habitat variation and jamming avoidance in echolocation calls of the sac-winged bat (Balantiopteryx plicata)

We have studied the effect of habitat and presence of conspecifics on echolocation characteristics of the emballonurid bat Balantiopteryx plicata. Calls during the search phase only showed differences between habitats in bandwidth, as has been found for other open-space bats. Characteristics of calls during the approach phase did change when bats entered open areas. Calls in the terminal phase showed no differences in the characters examined between habitats. Bats flying in groups shifted their peak frequency significantly, which maximized differences between individuals. These results are interpreted as an active mechanism of jamming avoidance. Bats flying in groups also tended to increase the mean of peak frequencies.Peer reviewe

Molecular phylogeography of Pteronotus davyi (Chiroptera: Mormoopidae) in Mexico

Pteronotus davyi, Davy's naked-backed bat, is a tropical bat whose current distribution in Mexico covers the watersheds of the Pacific and the Gulf coasts of Mexico, converges at the Isthmus of Tehuantepec, and continues into the Yucatan peninsula. We evaluated phylogeographic relationships among 18 populations in Mexico using data from the nucleotide sequence of the hypervariable II domain of the mitochondrial DNA control region from 105 specimens. Extant populations were distributed over 3 geographic regions (Pacific Coast, Gulf Coast, and Southeastern) that were delineated a priori according to floristic characteristics and biogeography. Coalescent simulations supported a phylogeographic model of 2 refugia situated in the south of Mexico (Arc and Soconusco refuges) during the late Pleistocene, followed by expansion into Pacific Coast, Gulf Coast, and Southeastern groups. The populations of the Southeast were genetically divergent from the Pacific and Gulf Coast populations, supporting the existence of 2 distinct lineages of P. davyi in Mexico, likely due to the Isthmus of Tehuantepec acting as a geographical barrier. Examination of our data revealed genetic differentiation of the Pacific and Gulf coastal groups but at a lower level relative to the Southeast. This pattern suggests that the Sierra Madre Occidental, Sierra Madre Oriental, and Sierra Madre del Sur act as physical barriers to dispersal for P. davyi.Peer reviewe

Dinámica poblacional, selección de sitios de percha y patrones reproductivos de algunos murciélagos cavernícolas en el oeste de México

Estudiamos la ecología poblacional y reproducción de algunas especies de murciélagos presentes en una cueva del oeste de México. Entre agosto 2003-marzo 2005 capturamos 16 409 individuos de los cuales 86.7% pertenecieron a miembros de la familia Mormoopidae, 7.4% a Phyllostomidae, 5.8% a N. mexicanus y 0.1% a B. plicata. Los números poblacionales de las especies varían notablemente a lo largo del año y entre temporadas. Segregación sexual durante la época reproductiva sucede en Pteronotus y N. mexicanus. Los mormópidos y N. mexicanus ocuparon las partes más profundas de la cueva donde imperan temperaturas >25.8°C y humedad >99%. Los filostómidos ocuparon las secciones intermedias con temperaturas de 23.2-28.3°C y humedad de 74-89.9%; B. plicata y G. sylvestris ocuparon una cámara con temperatura de 23.2°C y humedad del 84.2%. Los mormópidos y N. mexicanus exhibieron un patrón monoéstrico estacional, G. soricina presentó un patrón poliéstrico bimodal estacional y M. waterhousii exhibió un patrón reproductivo continuo. Nuestros resultados indican un reemplazamiento estacional entre varias especies, así como movimientos estacionales hacia otras cuevas. La selección de los sitios de percha esta ligada a las condiciones microclimáticas del refugio y la fisiología de las especies. La reproducción de las especies insectívoras esta influida por la precipitación que determina la disponibilidad del alimento