Gayana

Individual variation and potential geographic variation in the territorial song of Chucao tapaculo (Scelorchilus rubecula) in south-central Chile

2020-07-17T23:53:35-04:00

Se evalúa la variación individual y geográfica en los cantos territoriales de cinco poblaciones de Scelorchilus rubecula. Los resultados sugieren consistencia en los cantos a nivel individual y variación entre individuos de S. rubecula. Esta alta consistencia de los cantos individuales (66 - 91 %), indican que algunas variables (i.e., duración frase 1, FMA inicio frase 1, FMA final frase 2) pueden ser utilizadas para la identificación individual, mientras que a nivel geográfico/poblacional no se obtuvo una clara estructuración.

Assessing climatic and intrinsic factors that drive arthropod diversity in bird nests

2020-07-17T23:53:36-04:00

Bird nests are specialized structures that act as microrefuge and a source of food for arthropods. Nest arthropod richness and composition may vary according to the nest builder, geographical location and nest size. Because information on nest arthropods is scarce, there are even fewer studies on the drivers of nest arthropod diversity. We characterized arthropod diversity in cup- and dome-shaped nests along a 130 km latitudinal gradient in the mediterranean-type region of Central Chile and, we assessed whether nest dimensions and climatic factors explain richness (alpha-diversity). Then, we evaluated whether climatic differences between sites explain arthropod nest composition (beta-diversity). All collected nests hosted at least one arthropod specimen. We identified 43 taxonomic entities (4.2 entities per nest ± 0.5, mean ± SE, n = 27 nests) belonging to 18 orders and five classes: Arachnida, Diplopoda, Entognatha, Insecta and Malacostraca. We observed differences in nest arthropod richness and composition related to sites but not bird species. Larger nests supported greater arthropod richness. Furthermore, we observed that climatic differences explain the variation in arthropod composition between sites. Nests in the northern region (drier and warmer) mainly hosted Hemipterans and Hymenopterans. Contrary, nests in the southern region (humid and colder) hosted species of Collembola, Dermaptera, and Diplopoda. Positive relationship between nests surface area with arthropod richness suggests us that larger nests may keep more resources. Our study sheds light on a crucial interaction which may have potential consequences for insect assemblage composition and bird reproductive biology.

Wintry habitat selection of the Zapallaren tree iguana (Liolaemus zapallarensis, Müller & Hellmich, 1933) and its abundance in Changa beach, Coquimbo, northern Chile

2020-07-17T23:53:37-04:00

Urban development modifies the habitat of reptiles where we expect, the individuals to select available sites with the quality necessary for their permanence. The aim of this study was to determine the variables that favored the habitat selection and abundance of The Zapallaren Tree Iguana Liolaemus zapallarensis, an endemic species of Chile, during a winter season in Changa beach, Coquimbo, in northern Chile. Between June and September 2017, we made 30 random visits to 18 plots of 900 m2 each. We estimated a resource selection probability function for presence-absence and abundance data using local habitat (e.g. slope, distance from the protection wall to the sea at low tide, interior height of the wall, mean height of the vegetation, rocky surface, and vegetal surface) and climatic variables (temperature, atmospheric pressure, direction and wind speed, solar radiation, and mean cloudiness) as predictors. Vegetation cover was the most important habitat variable explaining the presence of L. zapallarensis. In addition, increase in cloudiness and wind speed decreased the probability of selection. Manly’s selectivity measure varied according to the established home ranges and the availability ratios within them. Finally, increase in cloudiness and wind speed decreased the abundance. Overall, our results show that the characteristics related to habitat and local climate influences the resource selection that favors the survival of reptiles. This work shows that beach sectors in urban contexts under anthropic pressure have important available resources that favor the presence and abundance of reptiles.

Estimating the climate change consequences on the potential distribution of Culex pipiens L. 1758, to assess the risk of West Nile virus establishment in Chile

2020-07-17T23:53:38-04:00

Climate change affects the dynamics of vector-borne diseases. Culex pipiens Linnaeus is the main vector of West Nile fever; a widely distributed arbovirus, it is continuously increasing its distribution. Using a species distribution model, maps of suitable habitats of Cx. pipiens were generated for Chile in the current climate and three climate change scenarios, using global and regional georeferenced vector presence records as input, plus bioclimatic variables. Since this virus has not yet arrived in Chile, the purpose of this study is to anticipate potential risk areas and to prevent the establishment and spread of the virus. Cx. pipiens is widely distributed in Chile. The suitable habitats in Chile were concentrated mostly from 32º to 35ºS, increasing in future scenarios up to 113 % in the northern zone and moving towards the mountains. This species conserves around 90 % of its niche in the future, and shows a reduction of 11.4 % in the severe climate change scenario. It is anticipated that Chile will experience an increase in the environmental suitability for Cx. pipiens moving from the Andes to the coastal zone throughout the country, mainly in the center-south. This will raise the risk of local virus transmission if the virus is introduced to the country via diverse routes.

Post-embryonic development and life table parameters of Neoseiulus californicus on Tetranychus desertorum and Panonychus citri (Acari: Phytoseiidae, Tetranychidae) under laboratory conditions

2020-07-19T12:02:23-04:00

The postembryonic development, and life table parameters of the Neoseiulus californicus were studied under laboratory conditions in order to evaluate the potentiality of this depredator for feeding on two phytophages mites Tetranychus desertorum (desert spider mite) and Panonychus citri (red spider mite). Tetranychus desertorum and P. citri may be considered as optimal food for N. californicus, which obtained survival rates of 100 %, on them. The time of the postembryonic development was significantly different (p < 0.05) between both diets. The periods of ovoposition, postoviposition and longevity of the N. californicus were 17.17; 4.37 and 22.53 days, respectively, fed with T. desertorum, and 14.84; 5.23 and 21.06 days, respectively, fed with P. citri. The demographic parameters of N. californicus obtained fed with T. desertorum and P. citri were: intrinsic rate of increase (r_m) = 0.269±0.004 and 0.307±0.004, mean generation time (T) = 12.847±0.185 and 10.791±0.142, net reproductive rate (Ro) = 31.792±1.478 and 27.352±1.187, finite rate of increase (λ) = 1.309±0.006 and 1.359±0.006, respectively. The high values of r_m and λ registered for N. californicus under experimental conditions are indicators of control potential that this phytoseiid presented as a predator over these phytophages mites.

Obituary Prof. Dr. Trevor Platt

2020-08-11T00:18:29-04:00

Current status of the marine bioinvasion research in Venezuela: topics and temporal trends

2020-07-23T00:41:38-04:00

Venezuela has one of the richest marine biodiversity areas in the world. Despite the high risk for the introduction of exotic species derived from historically high tourist activity and maritime transportation, the country does not have an updated revision to examine the main advances and gaps of knowledge in regards of biological invasions. This study aims to review the current state of knowledge regarding marine invasions in Venezuela, identifying the main research topics and the spatial and temporal trends. An extensive literature review carried out in multiple scientific databases showed that 35 articles were published between 1998 and 2018. Studies were conducted mainly on the eastern coast of the country. From the 94 species reported as exotic or cryptogenic, only 11 were studied under the context of biological invasions, most of them being first records. Contrary to the trend observed in most parts of the world, the number of studies decreased in the last decade, potentially related to the socio-political situation of the country. The current knowledge on biological invasions in Venezuela is pour. This important lack of information limits progress regarding prevention plans and increases risk for biosecurity and marine conservation of the country.

Evidence of predation on the Helmeted water toad Calyptocephalella gayi (Duméril & Bibron, 1841) by the invasive African clawed frog Xenopus laevis (Daudin 1802)

2020-07-17T23:53:41-04:00

We report the first record of predation on a Helmeted water toad Calyptocephalella gayi tadpole by an adult specimen of the invasive African clawed frog Xenopus laevis in the locality of Pichi, Alhué (Santiago Metropolitan Region). This finding is discussed in the light of new sightings, in which both species have been detected to coexist in different localities of central Chile.

Incorporation of bioethical standards for the generation of high quality scientific knowledge from research in wildlife: Science with conscience

2020-07-17T23:53:42-04:00

Research using wild animals has diverse aims, such as conservation, environmental management, and the generation of knowledge. The aim of the Institutional Animal Care and Use Committees (IACUCs) is to assure that such research is carried out under high bioethical and animal welfare standards, minimizing animal suffering and environmental impact. This manuscript highlights the relevance of IACUCs as an ally to adjust the procedures on animals to the norm and thus facilitate scientific progress.

Non-invasive genetic sampling of deer: a method for DNA extraction and genetic analysis from antlers

2020-07-20T21:22:23-04:00

We describe a non-invasive technique to isolate genomic DNA from connective tissue present in the antlers of deer of the genus Hippocamelus. This method is simpler and more effective than conventional more-destructive procedures which damage the collection material. This method is applicable to all cervids that annually regenerate their antlers.

On the taxonomic status of Liolaemus islugensis Ortiz and Marquet, 1987 (Squamata: Liolaemidae)

2020-07-24T00:11:25-04:00

We review the taxonomic status of Liolaemus islugensis Ortiz & Marquet, 1987, a scarcely known species belonging to the L. montanus group, that was propose as a junior synonym of L. pantherinus Pellegrin, 1909. The comparison of the original descriptions of both species and the review of the type material and other specimens allow us to validate L. islugensis. Liolaemus pantherinus is restricted to Bolivia and Peru, and L. islugensis is distributed in highlands of Chile and Bolivia.