Species In Uruguay Research Articles

Should I stay or should I fly: Aerial dispersal in a funnel‐web wolf spider from the grasslands of southern South America

AbstractBallooning is a mechanism of aerial dispersal present in some groups of spiders. By releasing silken threads that are blown by the wind, spiders can travel long distances through the air. Aglaoctenus lagotis is a wolf spider that lives its entire life associated with a funnel‐web, despite the wandering habit that characterizes species in this family. We can find two forms of the species in Uruguay, one of them a strict inhabitant of grasslands of Uruguay. The high habitat specificity and the spiderlings observed surrounding the maternal web suggest a low aerial dispersal capacity in this species. In this study, we tested whether A. lagotis spiderlings are capable of dispersing by ballooning. We conducted laboratory and field experiments during the day and night, to record the occurrence of ballooning and typical behaviours that precede ballooning. We recorded ballooning both in the laboratory and in the field, and it was more frequent during the day. Although it has been reported repeatedly in species from this family, we never observed the pre‐ballooning tip‐toeing behaviour in A. lagotis. Ballooning was preceded by dropping on dragline, considered a behaviour that could generate aerial dispersion of lesser distance than that generated by the tip‐toeing. In this paper, we shall discuss the implications of this form of aerial dispersal, considering that the species analysed is a web wolf spider.

Amazons Are Back: Absence of Males in a Praying Mantis from Uruguayan Savannas.

With a broad distribution throughout South America, Brunneria subaptera (Saussure)(Coptopterygidae) is the most abundant praying mantis species in Uruguay, mostly associated with grassland vegetation. Their body coloration can vary between green or brown sepia. The recent catalog of Uruguayan mantids showed that all specimens of B. subaptera from the collections in Uruguay were females, suggesting an absence of males in natural populations. The aim of this study was to determine the occurrence of female-only populations of B. subaptera in Uruguay. Moreover, we analyzed the genetic variation and estimated the time of the most recent common ancestor of the species. We performed bimonthly samplings in two localities in Uruguay for 1year and we sexed the individuals. We extracted DNA from the abdominal tissue of adult females and sequenced a fragment of the mitochondrial cox1 gene to assess the genetic diversity and to estimate diversification times. We did not find any males in either of the studied localities. The age estimates revealed a recent origin of the species (2.33Ma), and there was no genetic differentiation between the individuals from Uruguayan localities. This absence of males of B. subaptera documented in the sampled locations suggests that the species reproduces by thelytokous parthenogenesis. This study opens promising venues for future research into reproductive strategies and polymorphism in South-American praying mantises that inhabit one of the largest areas of grasslands in the world, currently under dramatic deterioration and reduction.

The last and endangered maned wolves (Chrysocyon brachyurus) from southern Brazil and Uruguay: new records and spatial distribution modeling

ABSTRACTThe biggest canid in the neotropics, the maned wolf (Chrysocyon brachyurus), is endangered in many parts of its distribution. Only eight records have been reported for Uruguay and the southern border of Brazil over the last 30 years. After a multi-year effort, we present nine new records for this area and characterize Uruguay and southern Brazil’s habitat suitability. Our records confirm the current presence of the species in Uruguay, the Brazilian Pampa, and the Atlantic highlands of southern Brazil, although no local population could be identified. Individuals appear to move in an erratic pattern, possibly when searching for other members of the species. Only three regions presented multiple records (all in the Atlantic highlands), indicating the possible existence of local populations. Although most of southern Brazil and Uruguay are highly suitable for the species, none of the 21 surveyed areas (with 50,816 camera trap nights) within putative distribution areas have confirmed the species occurrence, as all records reported here came from opportunistic encounters. In light of this, we believe that very few individuals still occur in the southern limit of the maned wolf distribution, and thus, the species can certainly be classified as critically endangered in the Brazilian Pampa/Uruguayan Savanna.

Endophytic and rhizospheric microbial communities associated with native and introduced cultivated plant species in Uruguay as sources for plant growth promotion bioinoculant development

Endophytic and rhizospheric microbial communities associated with native and introduced cultivated plant species in Uruguay as sources for plant growth promotion bioinoculant development

Economic analysis of alternatives for second rotations in Eucalyptus globulus plantations in southeast Uruguay

Eucalyptus globulus is one of the most planted forest species in Uruguay. However, its high susceptibility to diseases has determined that in recent years most plantations reaching harvest are replaced by other species, mainly E. dunnii and E. smithii. The decision whether to maintain the plantation for an additional rotation as coppice crop or to carry out a replanting depends on the expected economic results of both alternatives. Therefore, the objective of this research was to estimate the profitability of a coppice crop of E. globulus and that of a new plantation, with two different species, E. dunnii and E. smithii. In addition, a sensitivity analysis was carried out to study the impact of eventual variations in plantation productivity, in distance to the point of sale, and in the price of wood. Results showed that the three alternatives analyzed are economically viable, but that the management as coppice crop and the replanting with E. smithii are more profitable than replanting with E. dunnii. On the other hand, the coppice management is the alternative that requires less investment and that presents fewer risks, since it is less sensitive to changes in the main variables that determine the economic result.

Early stages of decay in Eucalyptus grandis trees inoculated with brown-rot fungi

In natural ecosystems, brown-rot fungi are major biodegrading agents of standing trees and dead wood. Decay caused by basidiomycetes results in structural instability and therefore negatively affects the quality and quantity of the produced wood. Fungal attack can also trigger defense mechanisms within the tree aimed at delaying or halting the progress of infection. As these defense mechanisms can decrease the value of the wood, their identification and study are of foremost importance. In this work, healthy trees of Eucalyptus grandis W.Hill — a widely commercialized species in Uruguay — were inoculated with Laetiporus sulphureus and Gloeophyllum trabeum. The decay process was characterized in terms of chemical and anatomical changes, and the defense mechanisms elicited by the tree were identified. Three months after inoculation, no symptoms of infection could be detected with the naked eye; however, microscopic analysis revealed anatomical and chemical changes (weakening, delamination, and rupture of vascular and parenchymal cells) and decreased holocellulose and lignin contents. Compartmentalization and the production of kino were used by the tree as defense mechanisms.

PRIMER REGISTRO DE LA CORVINA DE AGUA DULCE Plagioscion ternetzi BOULENGER 1895 (EUPERCARIA: SCIAENIDAE) EN EL RÍO QUEGUAY Y LA CUENCA DEL RÍO URUGUAY

In this study we report the first known record for the presence of the sciaenid species Plagioscion ternetzi in the Uruguay River Basin, at the specific location of the Queguay River, 20 km upstream from its mouth into the Lower Uruguay River. This finding extends the currently known distribution of the species in Uruguay (inner Río de la Plata Estuary) approximately 200 km northwards.

Relationship between Baccharis dracunculifolia DC. and B. microdonta DC. (Asteraceae) by Their Different Seasonal Volatile Expression.

Baccharis dracunculifolia DC. and Baccharis microdonta DC. (Asteraceae) are woody species morphologically similar growing in Uruguay, where not taxonomists people often confuse them in field conditions. As the essential oil of B. dracunculifolia ('vassoura' oil) is highly prized by the flavor and fragrance industry, the correct differentiation of the two species is a key factor in exploiting them profitably and reasonably. To differentiate both Baccharis species, in this work their volatile expression profiles were studied as an alternative tool to determine authenticity and quality. Volatile organic compounds (VOCs) were monthly extracted during an entire year from aerial parts of wild populations by simultaneous distillation extraction (SDE), and studied by gas chromatography/mass spectrometry (GC/MS; identification) and conventional gas chromatography (GC-FID; component abundances determination). Enantioselective gas chromatography/mass spectrometry (Es-GC/MS) was applied in the search of parameters able to ensure genuineness of each species extract. Qualitative VOCs profiles were found to be similar for both species, being β-pinene, limonene, spathulenol, caryophyllene oxide, and viridiflorol the main components. However, the abundance of those VOCs were two to ten times higher in B. dracunculifolia than in B. microdonta during the year of study. These Baccharis spp. showed species-specific patterns of VOCs expression according to the seasonality, and interestingly, oxygenated compounds (trans-pinocarveol and myrtenal) increased their abundances at full-flowering stages. The enantiomeric distribution of selected monoterpenes (α- and β-pinenes, limonene, linalool, terpinen-4-ol, and α-terpineol) presented differential values for both Baccharis spp., meaning that Es-GC might be a useful tool for differentiating chemically both species in Uruguay for genuineness determination purposes.

Modelling taper and stem volume considering stand density in Eucalyptus grandis and Eucalyptus dunnii

Eucalyptus grandis and Eucalyptus dunnii are the most planted tree species in Uruguay. Anticipating information about the quantity and quality of wood is important for managing intensive forest plantation. The estimate of merchantable and total wood volume is an essential tool in forest planning and management. The aim of this study was to evaluate four systems of taper and merchantable volume that consisted in a taper, a merchantable volume and a total tree volume function. A modified second-order continuous autoregressive error structure corrected the inherent serial autocorrelation of different observations in one tree. Taper and volume equations were fitted simultaneously after autocorrelation correction by full information maximum likelihood method. The segmented system proposed by Fang et al. (2000) produced the best fit as it explained more than 98% of the taper, merchantable volume and total volume variability for both species. In addition, precision of the segmented system was compared with and without incorporating stand density as a variable. Results of this analysis showed that for E. grandis, the predictive accuracy of the model was improved by including the stand density variable, whereas for E. dunnii this variable was not statistically significant. This modelling framework provides an improvement in taper and tree volume predictions for E. dunnii and E. grandis in Uruguay. The possibilities offered by this methodology could be of interest for its application in countries where fast growing plantations are managed.

Diversity of the Ganoderma species in Uruguay

ABSTRACT Ganoderma is a cosmopolitan genus that includes a great diversity of species. Many of them have been historically described based only on morphological characteristics; however, due to their morphological plasticity, there is no complete understanding about their relationship and taxonomic status. Commonly applied names, particularly in the southern Neotropics, come from species of North Hemisphere distribution (e.g. G. lucidum, G. resinaceum and G. applanatum). The objective of the present work was to perform a survey of Ganoderma species thriving in Uruguay. We aimed to identify and characterize them through molecular, morphological and ecological analysis. The results confirm the presence of four reddish laccate species first registered for Uruguay (G. dorsale, G. platense, G. martinicense and G. mexicanum), and one non-laccate species (G. australe s.l.) composed of two clades. The species are morphologically differentiated mainly by its stipe, pilear surface, context, pores, basidiospores and cutis cells. Regarding the ecological data, the species present differences in substrate preferences. In addition, a taxonomic discussion regarding phylogenetic relationships and taxonomic status of Uruguayan Ganoderma species is presented.

The Pampas Fox Lycalopex gymnocercus (Carnivora, Canidae) in the Late Pleistocene of Northern Uruguay

Canids are a very diverse and widely distributed group of carnivorous mammals. These animals entered South America in the early stages of faunistic interchange and later during the Pleistocene. However, the fossil record of these organisms is quite scarce on the continent, particularly in Uruguay. In the present contribution, two skulls associated with mandibles are described. Both materials were referred to as individuals of the Pampas fox Lycalopex gymnocercus, which was supported by morphological and morphometric analysis. These materials were found in late Pleistocene sediments (Sopas Formation) from different localities of northern Uruguay. Some aspects of their systematic and trophic dynamics are discussed. The remains of these animals have previously been listed but never described; thus, this material is the first fossil record reliably determined for this species in Uruguay.

<p><strong>Not extinct after all: rediscovery of <em>Commelina dielsii</em> (Commelinaceae) after 140 years, and first record of this species in Uruguay</strong></p>

Commelina dielsii is a species notable for being, together with the southern Brazilian C. catharinensis, the only native Commelina from the Americas with yellow petals. The species was up until now only known from the type gathering, made in 1878 in Entre Ríos province, north-eastern Argentina. Because it had not been collected since then, the species was considered as likely extinct. We present here the rediscovery of this species after 140 years, as the species was recently found in western Uruguay, in pampean environment. This also corresponds to the first record of the species in Uruguay. We also present field photographs, a morphological description, a distribution map for the species and its conservation status assessment.

First evidence of introgressive hybridization of apple snails (Pomacea spp.) in their native range.

Genetic variation facilitates both natural range expansions and anthropogenic invasions. Contrary to expectations, hybridization does not always impact negatively on biodiversity. Increasing evidence indicates advantageous roles for introgressive hybridization in maintaining standing genetic variation. Hypothesizing that hybridization may contribute to the evolutionary and invasive success of a diverse group of freshwater snails (Ampullariidae, commonly known as apple snails), we estimated the frequency of hybridization between two globally invasive species of Pomacea, Pomacea canaliculata (Lamarck, 1822) and P. maculata Perry, 1810, in their native range. While previous work in Asia has uncovered the occurrence of extensive hybridization, we provide the first phylogenetic evidence of a high degree of hybridization (30%) between these species in Uruguay and Brazil. Hybrids carried both heterozygous and homozygous combinations of elongation factor 1-α (EF1α) nuclear alleles in both mating directions, indicating that hybridization has occurred over multiple generations and likely preceded introductions outside the native range. Among the five sites in Brazil previously documented as containing only P. maculata, one far northern population (Careiro Castanho), which is thousands of kilometres from the northern range of P. canaliculata, unexpectedly contained hybrids. This may be the result of human-facilitated introductions. Together with recent work from Asia, our investigations in the native range of apple snails support a reframing of historical perspectives of hybridization as a driver of extinction and diversity loss towards a modern paradigm where hybridization may promote diversification and contribute to the survival of evolutionary lineages such as molluscs.

Influence of Temperature and Precipitation Anomaly on the Seasonal Emergence of Invasive Bark Beetles in Subtropical South America.

Several invasive bark beetle species have caused major economic and ecological losses in South America. Accurate predictions of beetle emergence times will make control efforts more efficient and effective. To determine whether bark beetle emergence can be predicted by season, temperature, or precipitation, we analyzed trapping records for three introduced pest species of bark beetles in Uruguay. We used trigonometric functions as seasonal predictors in generalized linear models to account for purely seasonal effects, while testing for effects of temperature and precipitation. Results show that all three beetle species had strong but unique seasonal emergence patterns and responded differently to temperature and precipitation. Cyrtogenius luteus (Blandford) emerged in summer and increased with precipitation but was not affected by temperature. Hylurgus ligniperda (Fabricius) emerged in winter and increased with temperature but was not affected by precipitation. Orthotomicus erosus (Wollaston) had a primary emergence in spring, and a smaller emergence in early summer, but showed no significant relationship with temperature or precipitation. This study shows that the emergence of these bark beetle species in Uruguay is influenced by seasonality more than by temperature and precipitation fluctuations. It also shows how seasonality can be easily incorporated into models to make more accurate predictions about pest population dynamics.

Identification of Earthworm Species in Uruguay Based on Morphological and Molecular Methods

Molecular techniques could aid earthworm species identification, especially when morphological characters are not taxonomically informative, or difficult to discern. No previous study has investigated molecular-based methods for earthworm taxonomy in Uruguay. The present study aimed to make a first approach using DNA barcoding as a tool to smoothen the way towards determining the earthworm richness in Uruguay. This study was based on an earthworm collection, identified both by morphological characters and molecular techniques, from samplings from different agricultural soils in Montevideo and Paysandú, Uruguay. Adult individuals were identified by external morphology following available descriptions of regional earthworms. From each morphological group a representative sample was selected for genomic DNA extraction, mitochondrial COI region amplification and sequencing. Sequences obtained were subject to BLAST searches and compared to sequences available in GenBank. Eight out of 11 sequenced exotic species were fully identified and matched morphological characters and molecular information; two were less consistent, with lower sequence similarity percentage; and one could not be fully identified due to lack of close related sequences in GenBank. While most exotic species had representative sequences annotated in GenBank, this was only the case for one native species, highlighting the need to develop this important area at a regional level. This study could kick-start an innovative research program, since there are limited records of earthworm samplings in Uruguay and no identification of species by DNA sequences from national studies.

Phenotypic, molecular and pathological characterization of motile aeromonads isolated from diseased fishes cultured in Uruguay.

Information about motile aeromonads from aquaculture systems of the Neotropical region is scarce. The aim of this study was to characterize motile Aeromonas isolated from ornamental and consumable fishes cultured in Uruguay. Biochemical and molecular methods were used for species identification. Antimicrobial susceptibility and the presence of virulence genes were evaluated. Genetic diversity was analysed by rep-PCR, and virulence of the most representative isolates was determined by calculating the fifty lethal dose in experimentally challenged fish (Australoheros facetus). Aeromonas hydrophila and A.veronii were the most prevalent identified species (38.2% and 32.4%, respectively), whereas A.allosacharophila, A.bestiarium, A.caviae and A.punctata were less prevalent. This study constitutes the first report of these last four species in Uruguay. All isolates were resistant to at least three antimicrobials, and 82.3% of them showed multidrug resistance. Virulence genotypes were correlated with the Aeromonas species and haemolytic activity. The genotype act+/alt+/ast+/ela+/lip+ was the most prevalent (26.5%). A correlation between virulence genotypes and Aeromonas species was found. A.punctata showed a clonal structure according to rep-PCR analysis, whereas other species showed high genetic diversity. The number of virulence genes of the isolates was related with virulence according to the experimental challenge assays.

The first artificial intelligence algorithm for identification of bat species in Uruguay

Acoustic bat identification is a complementary method to traditional mist-netting for chiropteran surveys. In this work, an algorithm based on artificial intelligence techniques was developed for bat species identification in Uruguay. An acoustic library of 662 search phase pulses of the 10 most common bat species in Uruguay was obtained. Random Forests, Support Vector Machines and Artificial Neural Networks algorithms were trained to predict bat species from acoustic variables. Variable selection was performed in an independent subset (one third) of the dataset, using the function varImpPlot of randomForest R package. Model performance was evaluated by means of the test error with the remaining two thirds of the data. To do this, data were split randomly into a training and a test set, then the model was trained with the training sample and its performance was assessed using the test sample. The procedure was performed 100 times and the test errors were averaged to have an unbiased measure of the performance of the models. The best predictor was a Random Forests classifier that considered 12 predictor variables. The achieved accuracy was comparable to other international published products. Additionally, a threshold value for classification probability was optimized to define an “unclassified” class that allows using this algorithm even when the training sample does not represent an exhaustive sample of local richness. A web application returning the predicted class and a confidence measure for a given observation was developed permitting the use of this tool by a broad spectrum of users, from biologist to technicians.

A wandering Weddell seal (Leptonychotes weddellii) at Trindade Island, Brazil: the extreme sighting of a circumpolar species

Records of vagrant marine organisms provide important information on oceanographic anomalies and the changing environment. We report on an immature Weddell seal, Leptonychotes weddellii, sighted at Calheta Beach in Trindade Island (20°31′S 29°19′W), Brazil, on July 9, 2015. A number of injuries were noted, including blisters on the dorsal surface of the body and a small cut at the right-hand side distal portion of the mandible. Based on its size and the state of fusion of cranial sutures, we suggest that it was born in the 2014 austral spring and was possibly 8–10 months old. We suggest that it comes from the South Shetland Islands, Antarctic Peninsula. This is the closest breeding location of this species. This sighting is the northernmost of L. weddellii, being at least ~ 5140 km from the Antarctic Peninsula (63°12′S 55°04′W) and ~ 2840 km north from the second northernmost sighting of this species in Uruguay.

Current status of American bullfrog, Lithobates catesbeianus, invasion in Uruguay and exploration of chytrid infection

The American bullfrog Lithobates catesbeianus is an invasive species that can strongly affect native amphibian communities through competition, predation, or introduction of diseases. This frog has invaded multiple areas in South America, for which niche models predict suitable environments across much of the continent. This paper reveals the state of the invasion of this species in Uruguay and its possible relationship with the chytrid pathogenic fungus, Batrachochytrium dendrobatidis. Surveys at invaded sites were conducted from 2007 to 2015, identified two populations undergoing recent range expansion (one of them exponential), two populations that failed to establish, and a new record in an urban area of the capital city, Montevideo. In all the analysed feral populations, chytridiomycosis was found. Our data suggest that the invasion of L. catesbeianus in Uruguay is at an early stage, with very localized populations, which might allow for the implementation of cost-effective management plans, with eradication constituting a plausible option.

Passive acoustic monitoring, development of disturbance calls and differentiation of disturbance and advertisement calls in the Argentine croaker Umbrina canosai (Sciaenidae).

Disturbance and advertisement calls of the Argentine croaker Umbrina canosai were recorded from coastal Uruguayan waters. Dissections indicate typical sciaenid extrinsic swimbladder muscles present exclusively in males. Disturbance calls were produced when captive U. canosai were startled, chased with a net or grabbed by the tail. Calls were unusual for sciaenids because each pulse consisted of multiple cycles. The number of cycles per pulse and dominant frequency did not change with U. canosai size, but pulse duration and interpulse interval increased. Advertisement calls were recorded from unseen choruses in the field and confirmed with captive individuals in a large tank. Advertisement calls were recorded throughout the known range of the species in Uruguay indicating a continuous belt of spawning populations. Tank recordings of the same individuals permitted explicit comparisons between the two calls. Advertisement call pulses averaged 2·4 more cycles (11·0-8·6) although pulses of both calls were basically similar as were durations and dominant frequencies. Pulse number, however, differed markedly, averaging 13·6 and 3·4 pulses for disturbance and advertisement calls respectively. Furthermore, disturbance calls were produced as a rapid series with an interpulse interval of 26-31 ms whereas advertisement call patterns were less stereotyped and ranged from <100 to 450 ms. Multicycle pulses distinguished U. canosai from other sympatric sciaenids.