Effects of Habitat and Fruit Scent on the Interactions between Short-tailed Fruit Bats and Piper Plants.

Piper is a mega-diverse genus of pioneer plants that contributes to the maintenance and regeneration of tropical forests. In the Neotropics, Carollia bats use olfaction to forage for Piper fruit and are a main disperser of Piper seeds via consumption and subsequent defecation during flight. In return, Piper fruits provide essential nutrients for Carollia year-round. There is evidence that the types and diversity of Piper frugivores are influenced by the primary habitat type of different Piper species (forest and gap), with forest Piper depending more on bats for seed dispersal; however, this pattern has not been tested broadly. We aimed to characterize and compare the interactions between Carollia and Piper across forested and gap habitats, and further investigate whether differences in fruit traits relevant to bat foraging (i.e., scent) could underlie differences in Carollia-Piper interactions. We collected nightly acoustic ultrasonic recordings and 24 h camera trap data in La Selva, Costa Rica across 12 species of Piper (six forest, six gap) and integrated this information with data on Carollia diet and Piper fruit scent. Merging biomonitoring modalities allowed us to characterize ecological interactions in a hierarchical manner: from general activity and presence of bats, to visitations and inspections of plants, to acquisition and consumption of fruits. We found significant differences in Carollia-Piper interactions between forested and gap habitats; however, the type of biomonitoring modality (camera trap, acoustics, diet) influenced our ability to detect these differences. Forest Piper were exclusively visited by bats, whereas gap Piper had a more diverse suite of frugivores; the annual diet of Carollia, however, is dominated by gap Piper since these plants produce fruit year-round. We found evidence that fruit scent composition significantly differs between forest and gap Piper, which highlights the possibility that bats could be using chemical cues to differentially forage for gap vs. forest Piper. By integrating studies of Piper fruit scent, plant visitation patterns, and Carollia diet composition, we paint a clearer picture of the ecological interactions between Piper and Carollia, and plant-animal mutualisms more generally.

Piper es un género megadiverso de plantas pioneras que contribuyen al mantenimiento y regeneración de los bosques tropicales. En el Neotrópico, los murciélagos de género Carollia utilizan el sentido del olfato para encontrar frutos de Piper y son los principales dispersores de estas plantas a través del consumo de los frutos y posterior defecación de las semillas durante el vuelo. A cambio, los frutos de Piper proporcionan nutrientes esenciales para Carollia durante todo el año. Existe evidencia de que los tipos y la diversidad de frugívoros que consumen Piper están influenciados por el tipo de hábitat primario (bosques y claros) de las diferentes especies, y que los Piper de bosque dependen más de los murciélagos para la dispersión de semillas. Sin embargo, este patrón no ha sido corroborado ampliamente. Nuestro objetivo fue caracterizar y comparar las interacciones entre Carollia y Piper en hábitats boscosos y en claros, e investigar más a fondo si las diferencias en los rasgos de las frutas relevantes para la búsqueda de frutos por los murciélagos (es decir, el olor) podrían explicar las diferencias en las interacciones entre Carollia y Piper. Para ello, compilamos grabaciones acústicas ultrasónicas durante la noche y videos con cámaras trampa por 24 horas/día en La Selva, Costa Rica, para 12 especies de Piper (6 de bosque, 6 de claros) e integramos esa información con datos sobre la dieta de Carollia y el aroma de los frutos de Piper. Esta combinación de modalidades de biomonitoreo nos permitió caracterizar las interacciones ecológicas de manera jerárquica: desde la actividad general y la presencia de murciélagos, sus visitas e inspecciones de las plantas, hasta la adquisición y consumo de frutos. Encontramos diferencias significativas entre hábitats boscosos y claros en las interacciones de Carollia y Piper;sin embargo, el tipo de modalidad de biomonitoreo (cámara trampa, acústica, dieta) influyó en nuestra capacidad de detectar estas diferencias. Los Piper de bosque fueron visitados exclusivamente por murciélagos, mientras que los Piper de claros tuvieron un grupo más diverso de frugívoros. La dieta anual de Carollia, sin embargo, está dominada por Piper de claros, ya que estas plantas producen frutos durante todo el año. Encontramos evidencia de que la composición del aroma de los frutos difiere significativamente entre los Piper de bosque y de claros, lo que resalta la posibilidad que los murciélagos puedan estar usando señales químicas para forrajear diferencialmente por Piper de estas dos categorías. La integración de estudios del aroma de los frutos de Piper, patrones de visita a las plantas y composición de la dieta de Carollia nos permitió generar una imagen más clara sobre las interacciones ecológicas entre Piper y Carollia y de los mutualismos planta-animal en general.

Contrasting thermal strategies of montane Neotropical bats at high elevations.

In the Neotropics, captive vespertilionid bats substantially reduce their metabolic rate at low ambient temperatures, similar to their temperate counterparts, whereas the ability of phyllostomids to lower metabolic rate seems to be more limited, even in mountain species. Nevertheless, field data on the thermal behaviour of syntopic individuals from these two families is lacking. Consequently, we aimed to test whether torpor was more common and deeper in vesper bats compared to leaf-nosed bats by studying skin temperature (Tsk) variation in individuals experiencing the same environmental conditions at a mountain area. Bats experienced ambient temperatures below 15 °C. Average Tsk was 10 °C in Myotis oxyotus gardneri (Vespertilionidae) during the day, while Sturnira burtonlimi (Phyllostomidae) regulated diurnal Tsk above 30 °C. Constant food availability may explain why diurnal Sturnira burtonlimi pay the high energetic cost required to remain normothermic and to defend a wide Ta-Tsk gap but further studies are needed to elucidate additional strategies that may be employed by these bats to reduce the energetic demands of normothermy. Our study shows that the contrasting thermal strategies and torpor use adopted by vespertilionid insectivores and phyllostomid frugivores in captive settings also occur in free-ranging conditions, thus providing a basis to develop further studies with predictions more accurately rooted in field data.

When genes move farther than offspring: gene flow by male gamete dispersal in the highly philopatric bat species Thyroptera tricolor.

For species characterized by philopatry of both sexes, mate selection represents an important behaviour for inbreeding avoidance, yet the implications for gene flow are rarely quantified. Here, we present evidence of male gamete-mediated gene flow resulting from extra-group mating in Spix's disc-winged bat, Thyroptera tricolor, a species which demonstrates all-offspring philopatry. We used microsatellite and capture-recapture data to characterize social group structure and the distribution of mated pairs at two sites in southwestern Costa Rica over four breeding seasons. Relatedness and genetic spatial autocorrelation analyses indicated strong kinship within groups and over short distances (<50 m), resulting from matrilineal group structure and small roosting home ranges (~0.2 ha). Despite high relatedness among-group members, observed inbreeding coefficients were low (FIS  = 0.010 and 0.037). Parentage analysis indicated mothers and offspring belonged to the same social group, while fathers belonged to different groups, separated by large distances (~500 m) when compared to roosting home ranges. Simulated random mating indicated mate choice was not based on intermediate levels of relatedness, and mated pairs were less related than adults within social groups on average. Isolation-by-distance (IBD) models of genetic neighbourhood area based on father-offspring distances provided direct estimates of mean gamete dispersal distances (r^) > 10 roosting home range equivalents. Indirect estimates based on genetic distance provided even larger estimates of r^, indicating direct estimates were biased low. These results suggest extra-group mating reduces the incidence of inbreeding in T. tricolor, and male gamete dispersal facilitates gene flow in lieu of natal dispersal of young.

Respuesta de lípidos y lipoproteínas en hombres sometidos a entrenamiento aeróbico / Response of lipid and lipoprotein in men in an aerobic training program

Se analiza la influencia de un programa de tratamiento aeróbico moderado, de 35 semanas de duración, sobre los niveles de lípidos (C.T.y TG) y lipoproteínas (HDL-C y LDL-C), en siete varones jóvenes. La concentración de HDL-C al cabo de 13 semanas de entrenamiento, fue mayor (P<0,05) que al incio (44,4 + - 5,4 vs 51,3 + - 6,9 mg/dl) y se mantuvo sin cambios significativos al cabo de 35 semanas (52,7 + - 7,7 mg/dl). La relación CT/HDL-C disminuyó respecto a los valores iniciales (p <0,02). No se presentaron variaciones significativas en los niveles de CT, TG y LDL-C. Cuando se comparó la respuesta observada en el grupo que entrenó, con un grupo de referencia (n=7), únicamente se observaron diferencias en los niveles de HDL-C (p<0,05) y en la relación CT/HDL-C (P< = 0,02). Por lo tanto, en este caso el entrenamiento aeróbico promovió cambios favorables en los niveles de HDL-C.