Gayana

Real and potential distribution of the hyperparasitoid genus Mesochorus Gravenhorst (Ichneumonidae: Mesochorinae) in Brazil

2020-05-14T14:28:45-04:00

Mesochorus species are hyperparasitoids capable of nullifying biological control agents. This study is the first to map and predict the distribution of this genus in Brazil. Species distribution modeling was used to estimate the potential distribution of Mesochorus. We obtained 72 occurrence records of 49 Mesochorus species, being 30 endemics. According to our prediction model, this genus can be distributed in all Brazilian biomes, with higher suitability of occurrence in the Atlantic Forest and lower in the Caatinga and Pampa.

Discovering new floral visitors of four Chilean endemic orchids

2020-05-14T15:14:36-04:00

Orchidaceae is a diverse group with conservation issues all over the World. Due to its endangered situation, knowledge about its reproductive biology is needed to plan conservation strategies. We conducted a study during October 2016 and October 2017 in Maule region, Chile, and discovered the following unreported interactions: Colletes seminitidus Spinola and Astylus trifasciatus Guér. transferring pollen from Bipinnula fimbriata; Centris nigerrima (Spinola) transferring pollen from Chloraea bletioides; Cadeguala occidentalis (Haliday) flower-visiting Chloraea gavilu; Centris cineraria Smith and Megachile saulcyi Guérin-Méneville transferring pollen from Gavilea venosa.

Southernmost records of Dromiciops gliroides: extending its distribution beyond the Valdivian rainforest

2020-05-14T15:34:44-04:00

The geographic range of a species is often limited by sampling approaches, underestimating the actual distribution. This is likely the case of Dromiciops gliroides (Microbiotheria), an endemic marsupial from southern South America. We used camera-traps to record D. gliroides for the first time in Chaitén and Futaleufú (southern Chile), expanding its known distribution 100 km to the south. Climate and forest composition in this area differs from the typical Valdivian rainforest. Activity assessments show a narrow activity patterns compared to northern populations.

Genetic diversity and demographic history of the endemic Southeastern Pacific sea urchin Arbacia spatuligera (Valenciennes 1846)

2020-05-14T10:40:17-04:00

The pattern of the genetic structuring of marine species result from the relationship between homogenizing and structuring factors, together with historical and contemporary processes. Dispersal potential has been described as a homogenizing factor, corroborated by the connectivity paradigm, which states that high dispersers show low or no genetic differentiation. In contrast, biogeographic breaks and oceanic currents have an important role in limiting or enhancing connectivity, being structuring factors. We studied this relationship in Arbacia spatuligera, a subtidal echinoid with a planktonic larval stage, which is distributed along the Southeastern Pacific (SEP). The SEP is divided into two biogeographic provinces with an Intermediate Area between both them, which is delimited by two biogeographic breaks (~30° S and 40°-42° S). Moreover, much of the SEP coast, from ~42° S to 6° S, it is influenced by a complex system of marine currents known as the Humboldt Current System (HCS). Using molecular tools (mtDNA COI) we assessed the genetic diversity and structure of A. spatuligera and inferred its demographic history. Analyses showed that along ca. 3.200 km A. spatuligera has no genetic structure signals, has an unexpected low genetic diversity and a signal of recent demographic expansion dated ~33000 - 47000 years ago, probably related to the Marine Isotope Stage 3 (MIS3) climatic events. Our results support the hypothesis that dispersal potential is a determining factor of the phylogeographic patterns in the SEP, probably influenced by HCS. We propose that A. spatuligera is a high disperser.

Relationship between thermal behavior and sex of a population of Pleurodema thaul (Amphibia: Leiuperidae) of the commune of Antuco, Biobío region

2020-05-14T10:57:35-04:00

Chile is a country that presents a variety of thermal environments under which diverse species of amphibians reside. For these, the environmental temperature (Ta) is important since it affects their body temperature (Tb). Due to the high phenotypic plasticity of this taxa, the aclimation temperature to which they are exposed in captive conditions can influence their thermal responses. In addition, body size and/ or mass may influence such behavior, and therefore, sexual dimorphism may differentiate Tc. Based on the above, Pleurodema thaul is an optimal object of study to evaluate thermal behavior since it presents sexual dimorphism in body size, and a strong influence of acclimation temperature on behavior. To analyze this association, individuals were collected in the commune of Antuco (Biobío Region) and subjected to two acclimation temperatures (10º and 20°C). Their size, mass, Tb and selected temperature (T_sel) were compared. The results show that in thermally homogeneous environments P. thaul is a tigmothermal species with a thermo-conformist behavior. The acclimation temperature did not present a significant effect on its behavior and they selected a wide thermal range with an average over 24°C where there were no significant differences between the sexes.

Prey selection by free-ranging dogs in the Estero Culebrón wetland (Coquimbo, Chile)

2020-05-14T13:47:57-04:00

We examine the factors that influence the selection of prey by stray dogs in the Estero Culebrón wetland (Coquimbo, Chile) and characterize their attacks during 20 visits in 2015. We use generalized lineal models considering the size of the bird, its relative abundance, site and type of substrate as explanatory variables. We recorded a pack of seven individuals who carried out 34 attacks on birds, of which the pelican had the highest predation frequency. The size of the bird and the site were positively related to the attacks. The selection of the pelican as prey could be related to its low flight initiation distance and large size, which facilitates the attack by dogs and, in addition, this greater size could sustain energetically to pack of dogs, especially when they are numerous. Other conditions such the absence of cattail (Typha angustipholia) and low water depth at the beach sector, would facilitate the development of attacks by reducing obstacles to persecution. Finally, due to the danger that these animals represent for the people and the fauna of wetlands, it is urgent to develop management plans that consider the retirement and transfer of them to rescue centers, as well as to implement sterilization and education campaigns.

Conservation in the city: How does habitat structure influence the abundance of individual bird species in a Latin American metropolis?

2020-05-14T14:01:04-04:00

A paucity of ecological research in urban ecosystems in Latin America limits the management of urban areas for biodiversity conservation. In addition, the majority of previous ecological studies in cities have focused on parks, ignoring most part of urban ecosystems. To provide robust scientific evidence for the management of urban areas for bird conservation, we investigate the influence of habitat variables on the abundance of native and exotic bird species in Santiago, Chile. During the reproductive season of 2017-2018, we surveyed birds and habitat variables at 455 points distributed throughout the city. We fit generalized linear models to evaluate the influence of habitat variables on individual bird species abundance. In 905 bird counts, we recorded 35 bird species (31 native and 4 exotic). The abundance of©2019 The author(s). Gayana ©2019 Universidad de Concepción. This open access article is distributed under the terms of the Creative Commons Attribution-NonCommercial native birds (Zenaida auriculata, Elaenia albiceps, Troglodytes aedon, Turdus falcklandii, Zonotrichia capensis and Molothrus bonariensis) increased with woody vegetation cover. Points with greater shrub cover in the microhabitat exhibited a greater abundance of T. falcklandii, Z. capensis and E. albiceps. In contrast to the response of native birds, the abundance of exotic species (Columba livia and Passer domesticus) decreased with vegetation cover. Our results demonstrate the importance of woody vegetation to conserve native bird species in Santiago. Management of habitat that (1) avoids the loss of woody vegetation and (2) aims to increase trees and shrubs in urban areas with low vegetation cover will promote a greater abundance of native birds.

Bacterial exopolysaccharides from extreme marine habitat of Southern Ocean: Production and partial characterization

2020-05-14T14:15:25-04:00

Deep marine microorganisms survive under extreme ecological settings and harsh environmental conditions of low temperature, high salinity, and high atmospheric pressure making it significant of scientific interest. Southern Ocean (SO) is one such example of deep marine ecosystem and the microorganisms inhabiting in such hostile environment may produce different bioactive secondary metabolites. SO (Indian Sector) is relatively less documented in terms of microbial composition and community dynamics. The present study involves isolation of exopolysaccharides (EPSs) from three potent SO (Indian Sector) bacteria, optimization of the EPS production and partial characterization of them. Three different EPSs show varying structural conformation, that is from porous to strong flakes mimicking polymeric structure with C/N ratio ranging between 4 - 11. FTIR spectra have exhibited the presence of different active groups of carbohydrate moieties, water molecules and protein-associated amides. EPSs produced by marine microorganisms show high biotechnological promises such as drug carrier in pharmaceutical field, emulsifier and cryo protectant in food-processing industry, detoxification of petrochemical oils and much more. The three bacterial isolates in this study showed potential of producing EPS biopolymer that can be further explored in terms of its proper biotechnological applications.