Thermoregulation of Liolaemus aparicioi (Iguania: Liolaemidae) along a 1000 m elevational gradient in La Paz Valley, La Paz, Bolivia.

Lizard species have diverse behavioral and physiological responses to thermo-environmental conditions, which allow them to inhabit a broad range of latitudes and elevations. Because the availability of suitable thermal resources is limited and more variable at high-elevation environments than at lower elevations, we expect high-elevation lizards to be constrained in their thermoregulation relative to lizards at lower elevations by the fewer available thermal resources to reach optimal temperatures (colder environment). We studied the thermal biology of an endemic and Critically Endangered lizard, Liolaemus aparicioi, to assess its thermal responses along a 1000 m elevational gradient in La Paz Valley from May to August of 2015 (dry season). We took field body and microhabitat temperatures at capture sites (substrate and air above ground), and body size (snout-vent length and mass) of individuals at Taypichullo (3000 m asl), Gran Jardín de la Revolución Municipal Park (3500 m asl), and Taucachi (4000 m asl) localities. Operative temperatures were taken from calibrated models deployed in different available microhabitats. Preferred temperatures and thermal tolerance limits were determined in laboratory settings for lizards from each locality. Field body, microhabitat, and operative temperatures decreased with increasing elevation and differed between sexes. Lizards at the high elevation locality had the lowest thermoregulatory efficiency as compared with the mid and lower elevation localities. In laboratory measurements, while the preferred temperatures varied between sexes, pooled preferred temperatures and thermal tolerances were similar in all localities. Although thermal resources at high elevation can limit thermoregulatory possibilities in L. aparicioi, behavioral microhabitat use, time allocated to thermoregulation, and physiological adjustments seem to be possible strategies to counteract thermal costs along elevational gradients.

Common opossum population density in an agroforestry system in Bolivia

The common opossum, Didelphis marsupialis thrives near human settlements. Understanding its ecology could help planning management decisions about this species, especially in anthropogenic landscapes. Yet, there are no density estimations for this species throughout its distribution range in Bolivia. We estimated the density of D. marsupialis in a rural agricultural community, where agroforestry plantations and fallows cover most of the land. We counted individuals in line transects and used DISTANCE software to calculate density. We covered a total of 70.21 km in 143 night counts, obtaining 38 records of D. marsupialis. We estimated a density of 0.30 individuals ha-1 (SE = 0.062; range: 0.20 - 0.45 individuals ha-1), with a mean encounter rate of 0.54 individuals km-1. Encounter rate varied between habitats, with mean values of 0.20 in secondary forests and 0.64 in agroforestry plantations. Our density estimate is near the lower range of previously reported values for the common opossum in other countries. We argue that our results may reflect the response to the availability of food resources and predation pressure in agroforestry plantations. (AU)

Sexual dimorphism in size and shape among populations of the lizard Sceloporus variabilis (Squamata: Phrynosomatidae).

Sexual dimorphism in lizards is determined by ecological and environmental factors. Broadly distributed species may show variation in patterns of sexual dimorphism toward either sex, as well as exhibiting variation in morphological dimensions. In the present study, sexual dimorphism in size and shape attributes was evaluated in three populations of the lizard Sceloporus variabilis from different environments in Mexico. We evaluated the size attributes of 10 morphological variables: snout-vent length (SVL), tibia length (TL), femur length (FeL), forearm length (FoL), interaxial distance (ID), head length (HL), head width (HW), head height (HH), jaw length (JL), and jaw width (JW). We also evaluated the attributes of shape (relative dimensions of the 10 morphological variables). In the size attribute, sexual dimorphism was found, with males being larger than females. In the case of shape, sexual dimorphism was found, with the females being larger in relative dimensions of ID and JW. Also, the males showed larger relative dimensions in TL, FeL and FoL. Differences were found between populations in the dimension of the variables analyzed in each sex. The pattern in size can be explained by sexual selection, where the males of each population maintain larger dimensions to compete for territory and access to females. In shape, females can be favored if they have larger relative ID and JW, as it promotes maintenance of clutch sizes, and use of microhabitats and different consumption of prey types than males. In the case of males, relative dimensions of TL, FeL and FoL may be functioning as important traits for escape from predators. The present study shows the importance of incorporating size and shape variables into analyses of sexual dimorphism among populations of a single species with a wide distribution. These types of studies help to identify the causes that promote sexual dimorphism, as well as the degree of difference among populations that inhabit different environments.

Home range and habitat use by pacas in a montane tropical forest in Bolivia / Ámbito de hogar y uso de hábitat del jochi pintado en un bosque montano tropical de Bolivia

ABSTRACT We studied the home range and habitat use of paca (Cuniculus paca) in a rural agricultural community in the Alto Beni region, in La Paz department, Bolivia, where game meat is the main source of protein for a large portion of local inhabitants. We captured and radio collared five individual paca (4 females and 1 male), which were followed for six months in 2012 to estimate home range of the individuals and assess their habitat use and selection. The total mean home range (95% Minimum Convex Polygon) was 2.26 ha (SD = 0.80), and ranged from 1.5 to 2.96 ha. The mean female home range (2.04 ha) was smaller than the male´s (2.95 ha). Pacas used two (crops and fallows) of the three available habitats (secondary forest patches), and appeared to positively select crops over the other two. The importance of crops may be linked to the type of agriculture conducted in the area (i.e. mainly cacao in agroforestry systems), which may offer more food and shelter for pacas. Given that, the importance of habitats may change seasonally; this topic should be examined in future studies. Our results suggest that agroforestry systems may be important for the species since they offer a variety of food resources throughout the year.

RESUMEN Hemos estudiado el ámbito de hogar y uso de hábitat del jochi pintado (Cuniculus paca) en una comunidad de Alto Beni en el Norte de La Paz-Bolivia, donde la carne obtenida por cacería es, como en muchas regiones de la Amazonia, una fuente principal de proteína para muchas poblaciones indígenas y campesinas. Hemos capturado y seguido con radio-collar a cinco individuos (4 hembras y 1 macho) por seis meses en 2012. El ámbito de hogar promedio de los individuos fue de 2,26 ha (ds=0,80), usando el estimador Mínimo Polígono Convexo (MPC al 95%) y los valores se encuentran entre 1,5 a 2,96 ha. El ámbito de hogar promedio de las hembras fue más pequeño (2,04 ha) que del macho (2,95 ha). Los jochis estudiados usaron 2 (cultivos y barbechos) de los 3 hábitats disponibles (parches de bosque secundario), aunque los cultivos parecen ser seleccionados positivamente respecto a los otros dos. La importancia de los cultivos podría estar ligada al tipo de cultivo que se realiza en la zona (sistemas agroforestales), que podrían estar ofreciendo mejores condiciones para ser usados por los jochis. Adicionalmente, la importancia de los hábitats podría cambiar de acuerdo a la época del año, lo cual podría ser abordado en siguientes estudios. Este trabajo es el primero en dar detalles sobre la ecología de C. paca en vida silvestre en Bolivia; sin embargo sería necesario contar con más individuos para tener más detalle sobre la ecología espacial de esta especie.

Dispersión de semillas de Mauritia flexuosa (Arecaceae) por frugívoros terrestres en Laguna Azul, Beni, Bolivia / Seed dispersal of Mauritia flexuosa (Arecaceae) by terretrial frugivores in Laguna Azul, Beni, Bolivia

El acopio esparcido ha recibido singular atención en las últimas décadas, y muchos estudios se han centrado en semillas de palmeras dispersadas por Dasyprocta. Nuestro objetivo fue identificar las especies consumidoras de frutos de Mauritia flexuosa, evaluar la importancia relativa de esas especies y el destino de las semillas dispersadas. Utilizamos experimentos de campo para evaluar el destino de las semillas removidas por frugívoros, en la Reserva de la Biosfera Pilón Lajas, Bolivia. Predijimos que las semillas enterradas por Dasyprocta tendrían menor mortalidad que las no enterradas. Colocamos 6-16 estaciones de frutos, con 15-50 frutos cada una, en cinco periodos de muestreo cubriendo un año. Los principales dispersores de M. flexuosa fueron D. punctata y Cuniculus paca, que transportan las semillas un máximo de 12.63 m y 14.1 m, respectivamente. Los dispersores removieron 7.5% de los frutos de las estaciones. Todas las semillas dispersadas en cuatro de los muestreos fueron depredadas o se pudrieron; solamente el 0.5% de las semillas dispersadas en febrero germinaron. De las semillas colocadas sobre y debajo del suelo en época seca y húmeda, solamente sobrevivieron aquellas enterradas en la época húmeda; el resto fueron depredadas o se pudrieron. Ninguna de las 84 semillas removidas por D. punctata fue enterrada, lo cual difiere de casi todos los reportes sobre el comportamiento de Dasyprocta. Discutimos este resultado en relación al posible efecto de la humedad del suelo y el tamaño de las semillas, y postulamos que la elevada abundancia del recurso haría innecesario acopiar semillas bajo suelo.

Scatterhoarding has received special attention for the last couple of decades, and several studies focused on palms whose seeds are dispersed by Dasyprocta. Our objective was to know the species that consume fruits of Mauritia flexuosa, to evaluate the relative importance of consumer species, and also to assess the fate of dispersed seeds. Using field experiments we evaluated the fate of seeds removed by frugivores at the Pilón Lajas Biosphere Reserve, Bolivia. We predicted that seeds buried by Dasyprocta would present lower mortality that those left unburied. We placed 6-16 fruit stations, with 15-50 fruits each, in five sampling periods along a year. The main seed dispersers of M. flexuosa were D. punctata and Cuniculus paca, which transported seeds a maximum of 12.63 m, and 14.1, respectively. Dispersers removed 7.5% of the fruits from the stations. All seeds removed during four out of the five sampling periods were either predated, or rotted; only 0.5% of the seeds dispersed in February germinated. From the total of seeds we buried in the dry and wet season only survived those buried in the wet season, the remaining were predated or rotted off. None of the 84 seeds removed by D. punctata were buried, which differs from all known reports on dispersal behavior of Dasyprocta. We discuss these findings in relation to the possible effects of soil humidity, and seed size and advance the hypothesis that the high abundance of the resource makes it unnecessary to scatterhoard seeds underground.

Mitigación de daños provocados por fauna silvestre en cultivos agrícolas en un bosque montano de Bolivia / Wildlife damage mitigation in agricultural crops in a Bolivian montane forest

Wildlife is often blamed for causing damage to human activities, including agricultural practices and the result may be a conflict between human interests and species conservation. A formal assessment of the magnitude of damage is necessary to adequately conduct management practices and an assessment of the efficiency of different management practices is necessary to enable managers to mitigate the conflict with rural people. This study was carried out to evaluate the effectiveness of agricultural management practices and controlled hunting in reducing damage to subsistence annual crops at the Cotapata National Park and Natural Area of Integrated Management. The design included seven fields with modified agricultural practices, four fields subjected to control hunting, and five fields held as controls. We registered cultivar type, density, frequency of visiting species to the field, crops lost to wildlife, species responsible for damage, and crop biomass. Most frequent species in the fields were Dasyprocta punctata and Dasypus novemcinctus. Hunted plots were visited 1.6 times more frequently than agriculturally managed plots. Crop lost to wildlife averaged 7.28% at agriculturally managed plots, 4.59% in plots subjected to hunting, and 27.61% in control plots. Species mainly responsible for damage were Pecari tajacu, D. punctata, and Sapajus apella. We concluded that both management strategies were effective to reduce damage by >50% as compared to unmanaged crop plots. Rev. Biol. Trop. 62 (4): 1495-1507. Epub 2014 December 01.

El daño causado por fauna silvestre en cultivos agrícolas es una de las causas principales de conflicto dentro y fuera de áreas protegidas. Para un adecuado manejo del conflicto se requieren evaluaciones del daño y de la aplicación de distintos métodos de mitigación. El objetivo del trabajo fue evaluar la efectividad de prácticas agroculturales y cacería de control, para reducir daños por vertebrados silvestres en cultivos agrícolas anuales en el PN ANMI Cotapata. Se trabajó en siete parcelas con prácticas agroculturales, cuatro parcelas con cacería de control y cinco parcelas control, registrándose el tipo y densidad de cultivo, frecuencia de visitas de especies dañinas a huelleros, plantación perdida, especies responsables y biomasa de cosecha. Los resultados muestran que las especies más frecuentes fueron: Dasyprocta sp. y Dasypus novemcinctus, siendo estas 1.6 veces más frecuentes en parcelas con prácticas agroculturales. En promedio se perdió 7.3% de la plantación en parcelas agroculturales, 4.6% en parcelas sujetas a cacería de control, y 27.6% en parcelas control. Las principales especies responsables de las pérdidas fueron: P. tajacu, seguido por Dasyprocta sp. y S. apella. A través de estas estrategias de manejo, redujo las pérdidas en >50%, con lo cual se considera que los métodos puestos a prueba son útiles y se recomienda utilizarlos a gran escala con la consideración de que podría ser necesario innovar cada cierto tiempo, pues los animales silvestres tienden a acostumbrarse a los métodos de ahuyentamiento en ejecución.

[Wildlife damage mitigation in agricultural crops in a Bolivian montane forest]. / Mitigación de daños provocados por fauna silvestre en cultivos agrícolas en un bosque montano de Bolivia.

Wildlife is often blamed for causing damage to human activities, including agricultural practices and the result may be a conflict between human interests and species conservation. A formal assessment of the magnitude of damage is necessary to adequately conduct management practices and an assessment of the efficiency of different management practices is necessary to enable managers to mitigate the conflict with rural people. This study was carried out to evaluate the effectiveness of agricultural management practices and controlled hunting in reducing damage to subsistence annual crops at the Cotapata National Park and Natural Area of Integrated Management. The design included seven fields with modified agricultural practices, four fields subjected to control hunting, and five fields held as controls. We registered cultivar type, density, frequency of visiting species to the field, crops lost to wildlife, species responsible for damage, and crop biomass. Most frequent species in the fields were Dasyprocta punctata and Dasypus novemcinctus. Hunted plots were visited 1.6 times more frequently than agriculturally managed plots. Crop lost to wildlife averaged 7.28% at agriculturally managed plots, 4.59% in plots subjected to hunting, and 27.61% in control plots. Species mainly responsible for damage were Pecari tajacu, D. punctata, and Sapajus apella. We concluded that both management strategies were effective to reduce damage by >50% as compared to unmanaged crop plots.

Altered neurotransmitter release, vesicle recycling and presynaptic structure in the pilocarpine model of temporal lobe epilepsy.

In searching for persistent seizure-induced alterations in brain function that might be causally related to epilepsy, presynaptic transmitter release has relatively been neglected. To measure directly the long-term effects of pilocarpine-induced status epilepticus on vesicular release and recycling in hippocampal mossy fibre presynaptic boutons, we used (i) two-photon imaging of FM1-43 vesicular release in rat hippocampal slices; and (ii) transgenic mice expressing the genetically encoded pH-sensitive fluorescent reporter synaptopHluorin preferentially at glutamatergic synapses. In this study we found that, 1-2 months after pilocarpine-induced status epilepticus, there were significant increases in mossy fibre bouton size, faster rates of action potential-driven vesicular release and endocytosis. We also analysed the ultrastructure of rat mossy fibre boutons using transmission electron microscopy. Pilocarpine-induced status epilepticus led to a significant increase in the number of release sites, active zone length, postsynaptic density area and number of vesicles in the readily releasable and recycling pools, all correlated with increased release probability. Our data show that presynaptic release machinery is persistently altered in structure and function by status epilepticus, which could contribute to the development of the chronic epileptic state and may represent a potential new target for antiepileptic therapies.

Metabolic gene expression changes in the hippocampus of obese epileptic male rats in the pilocarpine model of temporal lobe epilepsy.

Chronically epileptic male adult rats in the pilocarpine model of temporal lobe epilepsy (TLE), exhibited gross expansion of abdominal fat mass and significant weight gain several months after induction of status epilepticus (SE) when compared to control rats. We hypothesized that epileptogenesis can induce molecular changes in the hippocampus that may be associated with metabolism. We determined the expression levels of genes Hsd11b1, Nr3c1, Abcc8, Kcnj11, Mc4r, Npy, Lepr, Bdnf, and Drd2 that are involved in regulation of energy metabolism, in the hippocampus of age-matched control and chronic epileptic animals. Taqman-based quantitative real time polymerase chain reaction (qPCR) and the delta-delta cycle threshold (CT) methods were used for the gene expression assays. Gene expression of Hsd11b1 (cortisol generating enzyme) was significantly higher in epileptic versus control rats at 24h and 2 months, after induction of SE. Nr3c1 (glucocorticoid receptor) mRNA levels on the other hand were down-regulated at 24h, 10 days and 2 months, post SE. Abcc8 (Sur1; subunit of ATP-sensitive potassium (K(ATP)) channel) was significantly down-regulated at 10 days post SE. Kcnj11 (Kir6.2; subunit of ATP-sensitive potassium (K(ATP)) channel) was significantly up-regulated at 24h, 1 month and 2 months post SE. Thus, we demonstrated development of obesity and changes in the expression of metabolic genes in the hippocampus during epileptogenesis in male rats in the pilocarpine model of TLE.

Assembly of a model hydrophobic drug into cationic bilayer fragments.

Our previous work has shown that dioctadecyldimethylammonium bromide (DODAB) bilayer fragments (BF) presented antimicrobial activity, solubilized fungicides, e.g., amphotericin B and miconazole (MCZ), stabilized hydrophobic drug particles and were effective in vivo. Here, the interaction between MCZ and DODAB BF is evaluated from determination of BF loading capacity and effects of drug-to-lipid molar proportion (MP) on particle size, zeta potential and gel-to-liquid-crystalline phase transition T(m). DODAB BF solubilized MCZ over a range of MP. BF loading capacity was 0.5 mM MCZ at 5 mM DODAB. Above this limit, the drug aggregated in the dispersion. At pH 6.3, BF zeta potentials decreased with MP, suggesting insertion of deprotonated drug into the bilayer. MCZ optical spectra in BF were similar to those in best organic solvent, confirming drug solubilization. At MP 1:10, BF T(m) remained unchanged, suggesting drug capture at BF hydrophobic edges. At MP 1:10, T(m) decreased, showing MCZ insertion into DODAB bilayer. However, drug was expelled from the bilayer core upon lowering temperature. Minimal fungicidal concentrations against C. albicans were synergically reduced by 10 times for drug/BF.

Serologic evidence of nonfatal rabies exposure in a free-ranging oncilla (Leopardus tigrinus) in Cotapata National Park, Bolivia.

A clinically healthy free-ranging oncilla (Leopardus tigrinus) was live-trapped in Boliva in 2000. Based on serology, we concluded that this animal was exposed to feline panleukopenia virus, Toxoplasma gondii, and rabies virus. The rabies virus-neutralizing antibody titer (>70 IU/ml) in this oncilla was unusual for an asymptomatic animal exposed to street virus and at a level expected in animals exposed to a large amount of virus, clinically affected, or vaccinated. Based on a subsequent 18 mo of radiotracking, we concluded that the oncilla had a nonfatal exposure to rabies virus.

Genetic Structure of a Mimosoid Tree Deprived of Its Seed Disperser, the Spider Monkey.

To assess the genetic consequences for a Neotropical tree of the loss of its main seed disperser, we compared the genetic structure of Inga ingoides in a site where the spider monkey (Ateles paniscus) was abundant and a site where it had been eliminated by subsistence hunting. Gene flow should be reduced in the site where the spider monkey is absent, and there should be a corresponding subpopulation differentiation of seedlings within the spatial range of the movements of these primates in the absence of between-site differences in allelic frequencies. At the microhabitat ( family) scale, seedlings growing under parent plants should be genetically more related in the absence of the spider monkey than in its presence. Subpopulation differentiation was smaller where the spider monkey was present ( four loci, FST = 0.011) than where it was absent ( four loci, FST = 0.053) for the first year of study, but not for the second year (three loci, FST = 0.005 vs. 0.003). The number of alleles in common among seedlings growing under parent plants was smaller in the presence of the spider monkey than in its absence, showing family genetic structure in the first generation for both years of study ( Mann-Whitney, z = -2.17, p = 0.03 and z = -2.72, p = 0.006 for 1996 and 1997, respectively). This family genetic structure in the first generation should accelerate the development of population genetic structure. Development of genetic structure might result in demographic changes, one of which would be a fitness reduction if the species were self-incompatible, as suggested for Inga by available evidence. Large birds and mammals are the main targets of subsistence hunting in the Neotropics. Extinction of seed-dispersing frugivores may result in pronounced changes in the demographic and genetic structure of tree species in Neotropical forests.

RESUMEN: Para evaluar las consecuencias genéticas para una especie de árbol neotropical de la pérdida de su principal dispersor de semillas, comparamos la estructura genética de Inga ingoides entre un sitio con abundancia de marimono (Ateles paniscus) y otro donde éste había sido eliminado por cacería de subsistencia, en la estación Biológica Beni, Bolivia. El flujo génico debería estar reducido en ausencia del marimono, con una correspondiente diferenciación de subpoblaciones de plántulas dentro de la escala espacial de movimiento de dichos primates, si las frecuencias alélicas no difieren entre sitios. A escala familiar, las plántulas que crecen debajo de los parentales deberían estar más emparentadas entre sí en ausencia del marimono que en su presencia. La diferenciación de subpoblaciones fue mayor en ausencia del marimono (cuatro loci, FST = 0.053) que en su presencia (cuatro loci, FST = 0.011) para el primer año de muestreo, pero no así para el segundo año (tres loci, FST = 0.003 vs FST = 0.005). El número de alelos comunes para plántulas que crecen debajo de parentales fue mayor en ausencia del marimono, que en su presencia, evidenciando la formación de una estructura genética familiar en la primera generación para ambos años de muestreo (Mann-Whitney, z = −2.17, p = 0.03, y z = −2.72, p = 0.006 para 1996 y 1997, respectivamente). Esto aceleraría el proceso de estructuración genética a nivel poblacional. El desarrollo de estructura genética podría producir cambios demográficos, uno de los cuales sería la reducción en la adecuación biológica, si la especie es autoincompatible como lo sugiere la evidencia existente sobre Inga. La cacería de subsistencia se enfoca en los mamíferos y aves de gran tamaño. La extinción de frugívoros dispersores de semillas podría generar cambios grandes en la estructuración demográfica y genética en los bosques tropicales.