Eastern Colombia Research Articles

What can studying anacondas tell us about Titanoboa cerrejonensis? Exploring the life of an extinct giant snake using an extant pretty big snake

The maximum size that snakes can reach has been a matter of long held debate until the discovery of Titanoboa cerrejonensis (Boidae). It was an aquatic predator that lived 60–58 million years ago in what is currently eastern Colombia, occupying tropical swamps. It was calculated to measure 12.82 metres and it was speculated that it grew so much due to a warmer planetary weather. Its life history and ecology are speculated to be very similar to that of current day anacondas. Using data from a long-term study involving hundreds of green anacondas Eunectes murinus, this study makes inferences about aspects of the natural history of T. cerrejonensis that perhaps will not be easily available by studying the fossil record. Drawing parallels with anaconda's biology, I estimate that a non-breeding female T. cerrejonensis weighed approximately 1,232 kg, and 1,465 kg when pregnant. It would have started breeding at 480 cm SVL, weighing 95 kg. New-born Titanoboa were between 181 and 215 cm. Its average meal was estimated to be 505 kg, with a potential maximum of 1,799 kg. I estimate that Titanoboa had a growth rate of 0.046 mm/day compared with 0.036 in anacondas; which does not support the notion that it grew more due to a warmer planet. Although the results are largely speculative, they help give a better idea of what the life of an extinct snake was like. Keywords: Gigantism, prey size, reproductive biology, life history, palaeothermometer, giant snake, allometry, palaeoecology

Employing oxford nanopore technologies (ONT) for understanding the ecology and transmission dynamics of flaviviruses in mosquitoes (Diptera: Culicidae) from Eastern Colombia

Studies focused on identifying the viral species of Flavivirus in vectors are scarce in Latin America and particularly in Colombia. Therefore, the frequency of infection of the Flavivirus genus and its feeding preferences were identified in the mosquito species circulating in the municipality of Puerto Carreño-Vichada, located in the Eastern Plains of Colombia. This was done by sequencing the viral NS5 and vertebrate 12S rRNA genes, respectively, using Oxford Nanopore Technologies (ONT). A total of 1,159 mosquitoes were captured, with the most abundant species being Aedes serratus at 73.6% (n = 853). All the mosquitoes were processed in 230 pools (2–6 individuals) and 51 individuals, where 37.01% (n = 104) were found to be infected with Flavivirus. In these samples, infection by arboviruses of epidemiological importance, such as dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV), was ruled out by PCR. However, through sequencing, infection by different insect-specific viruses (ISFVs) and a medically important virus, West Nile virus (WNV), were identified in a mosquito of the Culex browni species. Additionally, the feeding patterns showed that most species present a generalist behavior. Given the above, conducting entomovirological surveillance studies is crucial, especially in areas of low anthropogenic intervention, due to the high probability that potentially pathogenic viruses could generate spillover events under deforestation scenarios.

DECIPHERING AN ENIGMA: FIRST RECORD OF Erythrolamprus aenigma (SQUAMATA: DIPSADIDAE) IN COLOMBIA

The Savanna racer snake Erythrolamprus aenigma is found in northern Brazil, Guyana and Venezuela. Here I present the first records of this species in eastern Colombia, extending the known distribution more than 1000 km east of its nearest range.

Magnetic Petrology applied to the characterization of Pegmatite Dykes in Eastern Colombia

In the sector of San Jose, Macanal, and Tabaquen, in eastern Colombia, granitic rocks cut by pegmatite dikes and quartz veins appear with the presence of magnetite, ilmenite, and ilmenorutile. Using magnetic petrology and geochemistry concepts and methods, the main objective is to determine if these types of rocks are genetically related and how the fluid chemically evolves during its crystallization and cooling. This work was conducted in three stages. Petrography and opaque metallography for identifying the occurrence, paragenesis, and secondary processes that transform the oxides. In a second stage and utilizing an Electron Probe Microanalyzer (EPMA), 214 quantitative analyses (WDS) and four compositional maps for magnetite, ilmenite, and ilmenorutile were performed, measu- ring the oxides FeO, TiO2, V2O3, MgO, MnO, Nb2O5, Ta2O5, Al2O3, Ga2O3, NiO, CaO, Cr2O3, SnO, and WO3. Since magnetite and ilmenite are favorable geothermometers that also allow the calculation of oxygen fugacity, the ILMAT program was used to calculate these values. In closing, integrate the data with the magnetic susceptibility values. The results determine crystallization temperatures between 358-414 °C for the granitic-host rock and 402- 499 °C for pegmatites dykes, in a system where oxygen fugacity increases, the Mn2+ is enriched in the ilmenite, and magnetite preserves a low content of trace elements thorough the evolution of the fluid. Taken together with the martitization and exsolution of hematite and rutile within ilmenite found in the petrography, these results allow us to conclude that an oxide-silicate re-equilibration process controls the evolution of this magmatic-hy- drothermal fluid with a KUIlB cooling trend-type reaction. Based on the Al + Mn vs. Ti + V ratio, the signature of the magnetite is like the Lucky Friday mine’s signature studied by Nadoll. However, the analysis of the 95th percentile shows a different concentration of trace elements in the magnetite of both sectors. Therefore, a new field of discrimination is proposed for this environment of anorogenic pegmatites of the NYF family. Finally, the magnetic susceptibility is controlled only by the abundance of magnetite in each type of rock. The granitic host rocks have the highest susceptibility values, followed by pegmatites and quartz veins with the lowest.

Relationship between coal composition, coal facies, and desorbed methane gas content: Thermal histories and exhumation processes in the middle Magdalena Valley basin, Colombia

We analyzed a total of 25 coal samples from high volatile bituminous to medium volatile bituminous range from 2 wells drilled in the Landázuri area of the Middle Magdalena Valley Basin at the Eastern Colombia Cordillera. This study reveals the relationship between the measured gas concentration, petrographic characteristics, and coal facies. We identify that gas desorption in coal seams is related to maceral composition.Three coal seam groups were defined in Landázuri 1 based on petrographic and statistical evaluation. Two groups were identified in Landázuri 2 based on gas content.The evaluation of maceral content and preservation of reflectance vitrinite found that the highest desorbed gas values correlate with the abundance of inertinite and structured inertinite macerals, followed by the percentage of vitrinite. Structured inertinite lumens may serve as macro/mesopores which allow for higher gas desorption because they are free of mineral matter or other macerals.Using existing coal facies diagrams, two types of coal facies were differentiated: lower delta plain (fen, marsh) and back-barrier low moor developed in a humid environment, where reotrophic conditions prevail and herbaceous and aquatic/marginal vegetation predominate.The relationship of these transitional facies with gas content shows are not directly related to the higher gas values measured at Landázuri. Instead, the relationship between the high degree of destruction of organic matter in these facies (marine incursions and other flows) and the measured gas content shows the importance of quantifying the structured macerals as potential gas retainers.Using low-temperature thermochronometers apatite fission-track, and (U–Th)/He in zircon, combined with vitrinite reflectance data, we reconstructed time-Temperature histories for areas near the wells. Differences in gas content can be explained by an asynchronous behaviour of the burial-cooling processes in this part of the Colombian Eastern Cordillera. Our work shows it is possible to distinguish gas desorption in coal seams based on the maceral composition.

A dynamic simulation model to assess farm-level effects of pasture intensification strategies on beef herd outputs and carbon footprints in acid soil savannas of Eastern Colombia

The neotropical savannas of Eastern Colombia (Llanos) are subjected to changes in land use associated with intensification of beef production and there is limited knowledge on the long-term impacts of these change processes. Furthermore, the effects of spatial and temporal intensification at farm level via the introduction of sown pastures on beef herd outputs, their greenhouse gas (GHG) emissions and the resulting carbon (C) footprints in contrasting savanna landscapes of of the Llanos are unknown. This study was aimed to assess the consequences of gradual system intensification via introduction of sown tropical pastures in two contrasting landscapes, the tillable, flat savannas and the highly dissected rangelands, of the well-drained Eastern savannas of Colombia, in terms of cow-calf production and GHG emissions and the resulting C footprints. A dynamic model was developed to simulate the gradual introduction of two types of tropical pastures in a region with dissected and steep slopes and limited tillable areas where cattle would also have access to Serrania savanna and sown pastures, versus one located in the Plains that are fully transformed over time with the exclusion of native rangelands. Marked changes in herd demography, animal outputs, and emissions were found over time. The C footprint of all systems varied over time depending upon the length of time that pastures contributed to soil organic carbon accumulation and the balance between savanna and sown pasture areas at a whole farm level. In conclusion, the dynamics of the systems subject to intensification were marked and were dependent on the temporal and spatial deployment of sown forage resources. Therefore, generalizing the trends for the region as a whole result in uncertainty. Nevertheless, examination of simulated prototypes may shed light on the expected trends and provides guidance for decision-making

Biomass and carbon stocks of four vegetation types in the Llanos Orientales of Colombia (Mapiripán, Meta)

Agricultural lands occupy 38% of global land surface and are expected to grow significantly in the next years, increasing the need for more sustainable practices, as well as better informed conservation practices of natural ecosystems. Carbon stocks are important estimates for the assessment of potential emissions caused by deforestation, and therefore widely used in strategies to mitigate climate change in agroforestry systems. Although research on biomass and carbon accumulation in agricultural lands is well documented, comparisons with adjacent natural forest areas are uncommon, mainly in tropical regions. Here, we used forest inventory data and allometric models to estimate biomass and carbon stocks of natural vegetation types (gallery forest-GF, morichal-MOR, and savanna-SAV) and oil palm (Elaeis guineensis) crops in the Orinoquía bioregion, in Eastern Colombia. We found that natural forests (GF and MOR) hold 542.45 Mg ha−1 of aboveground biomass, whereas oil palm plantations store 284.87 Mg ha−1. Morichal vegetation, commonly known as peat swamp forests, accumulated the highest aboveground biomass and carbon per hectare among all vegetation types (natural and agricultural), with an estimate of 402.76 Mg ha−1. Thus, although oil palm crops are great reservoirs of biomass and carbon at the landscape level, it is the combination of natural and agricultural lands which assure highest carbon sequestration in the study area. These results highlight the importance of preserving natural areas in agricultural landscapes for climate mitigation and conservation of biodiversity, which may jointly benefit plantations sustainable development.

Prey resources are equally important as climatic conditions for predicting the distribution of a broad‐ranged apex predator

AbstractAimA current biogeographic paradigm states that climate regulates species distributions at continental scales and that biotic interactions are undetectable at coarse‐grain extents. However, advances in spatial modelling show that incorporating food resource distributions are important for improving model predictions at large distribution scales. This is particularly relevant to understand the factors limiting the distribution of widespread apex predators whose diets are likely to vary across their range.LocationNeotropical Central and South America.MethodsThe harpy eagle (Harpia harpyja) is a large raptor, whose diet is largely comprised of arboreal mammals, all with broad distributions across Neotropical lowland forest. Here, we used a hierarchical modelling approach to determine the relative importance of abiotic factors and prey resource distribution on harpy eagle range limits. Our hierarchical approach consisted of the following modelling sequence of explanatory variables: (a) abiotic covariates, (b) prey resource distributions predicted by an equivalent modelling for each prey, (c) the combination of (a) and (b), and (d) as in (c) but with prey resources considered as a single prediction equivalent to prey species richness.ResultsIncorporating prey distributions improved model predictions but using solely biotic covariates still resulted in a high‐performing model. In the Abiotic model, Climatic Moisture Index (CMI) was the most important predictor, contributing 76% to model prediction. Three‐toed sloth (Bradypus spp.) was the most important prey resource, contributing 64% in a combined Abiotic‐Biotic model, followed by CMI contributing 30%. Harpy eagle distribution had high environmental overlap across all individual prey distributions, with highest coincidence through Central America, eastern Colombia, and across the Guiana Shield into northern Amazonia.Main ConclusionsWith strong reliance on prey distributions across its range, harpy eagle conservation programmes must therefore consider its most important food resources as a key element in the protection of this threatened raptor.

Pratylenchus Araucensis (Rhabditida: Pratylenchidae) a Widely Distributed Nematode in Musa Spp. from Colombia.

Pratylenchus is one of the most limiting nematodes of Musaceae production in the world. Knowledge of the nematode species is one of the requirements for its management in the field. This study aimed to identify up to the species level Pratylenchus populations associated with plantain and banana crops in the states of Caldas, Quindío, and Valle del Cauca in Colombia. In these regions, Pratylenchus has been reported to affect these crops in the past, but with records of the nematode only up to the genus level. For this purpose, five populations of Pratylenchus extracted from samples composed of roots and rhizospheric soil, four from plantain and one from banana, were identified through morphological, morphometric, and molecular analysis (sequencing of the D2-D3 of rRNA and cytochrome oxidase subunit I of mtDNA). All populations were identified as P. araucensis, a species reported previously in eastern Colombia, and one that the present study found in the center and southwest of the country, indicating that this species of nematode is widely distributed in the Musaceae-producing areas of Colombia. The present study reports the first COI mtDNA sequences for this species of nematode.

Densidade de estocagem de tilápia vermelha (Oreochromis sp.) criada em sistema comercial de bioflocos na Colômbia

ABSTRACT Biofloc technology (BFT) has several advantages, such as low water supply requirements and apparent feed conversion ratio (FCR), and high densities. However, there is no information on adequate densities and their effect on the large-scale production of different species. In this study, we determined the effects of the stocking density of monosex red tilapia reared using BFT on the growth performance, water quality parameters, and chemical characteristics of fish on a large scale and under culture conditions in eastern Colombia. In total, six circular tanks (diameter: 14 m, height: 1 m, and capacity: 153 m³) were used in this investigation. Two stocking densities were considered: treatment 1 (T30: 30 fish/m³) and treatment 2 (T40: 40 fish/m³), in triplicate. The water quality parameters of the two treatment densities were within the normal ranges for the species, but dissolved oxygen decreased throughout the production process. The T30 and T40 treatments did not result in significant differences in growth performance. At the end of the trial, the FCRs were 1.6 and 1.7 from T30 and T40, respectively. Fishes raised at a lower density had a similar weight gain; however, their final biomass was not significantly different. BFT did not affect the nutritional characteristics of fish; the percentage of protein (%) in tilapia was 17.81% ±1% and 16.72% ±1% in the T30 and T40 groups, respectively. None of the fish were infected by Salmonella spp. or Vibrio cholerae.

Colombian soil texture: building a spatial ensemble model

Abstract. Texture is a fundamental soil property for multiple applications in environmental and earth sciences. Knowing its spatial distribution allows a better understanding of the response of soil conditions to changes in the environment, such as land use. This paper describes the technical development of Colombia's first texture maps, obtained via a spatial ensemble of national and global digital soil mapping products. This work compiles a new database with 4203 soil profiles, which were harmonized at five standard depths (0–5, 5–15, 15–30, 30–60, and 60–100 cm) and standardized with additive log ratio (ALR) transformation. A compilation of 83 covariates was developed and harmonized at 1 km2 of spatial resolution. Ensemble machine learning (EML) algorithms (MACHISPLIN and landmap) were trained to predict the distribution of soil particle size fractions (PSFs) (clay, sand, and silt), and a comparison with SoilGrids (SG) products was performed. Finally, a spatial ensemble function was created to identify the smallest prediction errors between EML and SG. Our results are the first effort to build a national texture map (clay, sand, and silt fractions) based on digital soil mapping in Colombia. The results of EML algorithms showed that their accuracies were very similar at each standard depth, and were more accurate than SG. The largest improvement with the spatial ensemble was found at the first layer (0–5 cm). EML predictions were frequently selected for each PSF and depth in the total area; however, SG predictions were better when increasing soil depth in some specific regions. The final error distribution in the study area showed that sand presented higher absolute error values than clay and silt fractions, specifically in eastern Colombia. The spatial distribution of soil texture in Colombia is a potential tool to provide information for water-related applications, ecosystem services, and agricultural and crop modeling. However, future efforts need to improve aspects such as treating abrupt changes in the texture between depths and unbalanced data. Our results and the compiled database (https://doi.org/10.6073/pasta/3f91778c2f6ad46c3cc70b61f02532db, Varón-Ramírez and Araujo-Carrillo, 2022, https://doi.org/10.6073/pasta/d6c0bf5847aa40836b42dcc3e0ea874e, Varón-Ramírez et al., 2022) provide new insights to solve some of the aforementioned issues.

Interrogating the transmission dynamics of Trypanosoma cruzi (Trypanosomatida, Trypanosomatidae) by Triatoma venosa (Hemiptera: Reduviidae) after the elimination of vector transmission by Rhodnius prolixus in Boyacá eastern Colombia.

Chagas disease (CD) is a parasitic zoonosis (Trypanosoma cruzi) that is endemic in Colombia. Vector control of Rhodnius prolixus, the main domestic T. cruzi vector, has been achieved in a large part of the area with historically vector transmission of CD. It is necessary to understand the ecological behavior characteristics of local native vectors to ensure sustainability of the vector control programs. To evaluate the long-term success of a recent vector control campaign in the Boyacá department (Colombia), we used a combined strategy of entomological surveillance with co-existing canine surveillance from ten rural villages within six municipalities of the Tenza valley region (Boyacá, Colombia): Chinavita, Garagoa, Guateque, Somondoco, Sutatenza and Tenza, with historical reports of R. prolixus and secondary vectors. Collected triatomines and canine whole blood were analyzed for T. cruzi infection and genotyping. Triatomine bugs specimens were evaluated for blood meal source. Canine serology was performed using two distinct antibody assays. In total, 101 Triatoma venosa were collected by active search in domestic and peridomestic habitats. A natural infection prevalence of 13.9% (14/101) and four feeding sources were identified: human, dog, rat, and hen. A frequency infection of 46.5% (40/87) was observed from two independent serological tests and T. cruzi DNA was detected in 14 dogs (16.4%). Only TcIsylvatic DTU was detected. The results suggest that T. venosa present eco-epidemiological characteristics to maintain the transmission of T. cruzi in Tenza valley. This species has reinfested the intervened households and it has an active role in domestic and peridomestic transmission of T. cruzi due to their infection rates and feeding behavior. Therefore, this species should be considered as epidemiologically relevant for vector control strategies. Moreover, there is a need for human serological studies to have a close up of risk they are exposed to.

Genetic Instability among Hitnü People Living in Colombian Crude-Oil Exploitation Areas.

Oil exploitation, drilling, transportation, and processing in refineries produces a complex mixture of chemical compounds, including polycyclic aromatic hydrocarbons (PAHs), which may affect the health of populations living in the zone of influence of mining activities (PZOI). Thus, to better understand the effects of oil exploitation activities on cytogenetic endpoint frequency, we conducted a biomonitoring study in the Hitnü indigenous populations from eastern Colombia by using the cytokinesis micronucleus cytome assay (CBMN-cyt). PAH exposure was also measured by determine urine 1-hydroxypyrene (1-OHP) using HPLC. We also evaluated the relationship between DNA damage and 1-OHP levels in the oil exploitation area, as well as the modulating effects of community health factors, such as Chagas infection; nutritional status; and consumption of traditional hallucinogens, tobacco, and wine from traditional palms. The frequencies of the CBMN-cyt assay parameters were comparable between PZOI and Hitnü populations outside the zone of influence of mining activities (POZOI); however, a non-significant incremental trend among individuals from the PZOI for most of the DNA damage parameters was also observed. In agreement with these observations, levels of 1-OHP were also identified as a risk factor for increased MN frequency (PR = 1.20) compared to POZOI (PR = 0.7). Proximity to oil exploitation areas also constituted a risk factor for elevated frequencies of nucleoplasmic bridges (NPBs) and APOP-type cell death. Our results suggest that genetic instability and its potential effects among Hitnü individuals from PZOI and POZOI could be modulated by the combination of multiple factors, including the levels of 1-OHP in urine, malnutrition, and some traditional consumption practices.

Variability of Precipitation Recycling and Moisture Sources over the Colombian Pacific Region: A Precipitationshed Approach

This study assessed the precipitation recycling and moisture sources in the Colombian Pacific region between 1980–2017, based on the monitoring of moisture in the atmosphere through the Eulerian Water Accounting Model-2 layer (WAM2 layer) and the delimitation of the area contributing to terrestrial and oceanic moisture in the region is performed using the “precipitationshed” approach. The results indicate a unimodal precipitation recycling ratio for the North and Central Pacific and Patía-Mira regions, with the highest percentages between March and April, reaching 30% and 34%, respectively, and the lowest between September and October (between 19% and 21%). Moreover, monthly changes in the circulation of the region promote a remarkable variability of the sources that contribute to the precipitation of the study area and the spatial dynamics of the precipitationshed. From December to April, the main contributions come from continental sources in eastern Colombia and Venezuela, the tropical North Atlantic, and the Caribbean Sea, a period of high activity of the Orinoco Low-Level jet. In September, the moisture source region is located over the Pacific Ocean, where a southwesterly cross-equatorial circulation predominates, converging in western Colombia, known as the Choco Jet (CJ), decreasing the continental contribution. An intensified Caribbean Low-Level Jet inhibits moisture sources from the north between June and August, strengthening a southerly cross-equatorial flow from the Amazon River basin and the southeastern tropical Pacific. The March–April (September–October) season of higher (lower) recycling of continental precipitation is related to the weakening (strengthening) of the CJ in the first (second) half of the year, which decreases (increases) the contribution of moisture from the Pacific Ocean to the region, increasing (decreasing) the influence of land-based sources in the study area.

Estimating the genetic structure of Triatoma dimidiata (Hemiptera: Reduviidae) and the transmission dynamics of Trypanosoma cruzi in Boyacá, eastern Colombia.

Chagas disease is considered a public health issue in Colombia, where many regions are endemic. Triatoma dimidiata is an important vector after Rhodnius prolixus, and it is gaining importance in Boyacá, eastern Colombia. Following the recent elimination of R. prolixus in the region, it is pivotal to understand the behavior of T. dimidiata and the transmission dynamics of T. cruzi. We used qPCR and Next Generation Sequencing (NGS) to evaluate T. cruzi infection, parasite load, feeding profiles, and T. cruzi genotyping for T. dimidiata specimens collected in nine municipalities in Boyacá and explored T. dimidiata population genetics. We found that T. dimidiata populations are composed by a single population with similar genetic characteristics that present infection rates up to 70%, high parasite loads up to 1.46 × 109 parasite-equivalents/mL, a feeding behavior that comprises at least 17 domestic, synanthropic and sylvatic species, and a wide diversity of TcI genotypes even within a single specimen. These results imply that T. dimidiata behavior is similar to other successful vectors, having a wide variety of blood sources and contributing to the circulation of different genotypes of the parasite, highlighting its importance for T. cruzi transmission and risk for humans. In the light of the elimination of R. prolixus in Boyacá and the results we found, we suggest that T. dimidiata should become a new target for vector control programs. We hope this study provides enough information to enhance surveillance programs and a future effective interruption of T. cruzi vector transmission in endemic regions.

Modelling the reproductive performance of tropical beef herds using long-term experimental grazing data on Urochloa humidicola pastures in the Llanos of Colombia

Long-term reproductive performance of beef breeding herds grazing sown pastures in the neotropical savanna environment of Eastern Colombia (Llanos) is not well documented, while the lifelong reproductive consequences of raising replacement heifers subject to different growth regimes is also intriguing. The study aimed to assess the effects of liveweight (LW), age, and their interaction on conception probabilities of Bos indicus replacement females by analyzing two seven- and eight-years lasting experiments that used commercial Brahman heifers subject initially to different growth rates on Urochloa humidicola pastures. The experiments included two periods, namely the growth period from weaning until 270 kg LW during which heifers were subjected to three stocking rates to attain different rates of gain, and the subsequent reproduction phase subject to common grazing for all growth treatments. The conception data fitted well logistic regressions in which LW and age were the predictor variables during the first two conceptions but the relationship disappeared in subsequent conceptions. Prediction equations compared well with extensive data from northern Australia that showed similar trends. Liveweight of adult cows only increased consistently during pregnancy, but following weaning their LWs returned to the initial low LWs attained at conception. Over the length of the experiments, weaning rates as percentages of calves born were 88% for the two treatments with higher LW gains during the growth period, and 81% for the lowest gaining treatment. Calving intervals were 19-20 months across treatments. It is suggested that the data and equations provided can guide decision making in extensive breeding herds.

Towards environmental detection of Chagas disease vectors and pathogen

Chagas disease vector control relies on prompt, accurate identification of houses infested with triatomine bugs for targeted insecticide spraying. However, most current detection methods are laborious, lack standardization, have substantial operational costs and limited sensitivity, especially when triatomine bug densities are low or highly focal. We evaluated the use of FTA cards or cotton-tipped swabs to develop a low-technology, non-invasive method of detecting environmental DNA (eDNA) from both triatomine bugs and Trypanosoma cruzi for use in household surveillance in eastern Colombia, an endemic region for Chagas disease. Study findings demonstrated that Rhodnius prolixus eDNA, collected on FTA cards, can be detected at temperatures between 21 and 32 °C, when deposited by individual, recently blood-fed nymphs. Additionally, cotton-tipped swabs are a feasible tool for field sampling of both T. cruzi and R. prolixus eDNA in infested households and may be preferable due to their lower cost. eDNA detection should not yet replace current surveillance tools, but instead be evaluated in parallel as a more sensitive, higher-throughput, lower cost alternative. eDNA collection requires virtually no skills or resources in situ and therefore has the potential to be implemented in endemic communities as part of citizen science initiatives to control Chagas disease transmission.

On the occurrence of Scinax kennedyi (Pyburn, 1973) (Anura, Hylidae) in the state of Roraima, northern Brazil

Scinax comprises 129 species of treefrogs divided between the S. ruber and the S. catharinae clades. The S. rostratus group belongs to the S. ruber clade, and comprises ten species characterized by having a dark interorbital triangular mark, tubercle on the heel and by vocalizing in a head-down position. Within this group, S. kennedyi and S. rostratus are similar in that they are the only species that do not possess a row of tubercles on the lower jaw. In spite of their morphological similarity, they can be distinguished from each other by male size and advertisement call traits. Scinax kennedyi was described from eastern Colombia, and occurs from central Colombia to western Venezuela, whereas S. rostratus was described from northern Venezuela, and is thought to occur from Panama to eastern Venezuela, and in the Brazilian state of Pará. A recent study reported a population identified as S. rostratus from the state of Roraima, in northern Brazil. However, this population presented substantial differences in male size and advertisement call in comparison to the described for this species, and apparently it best fits the diagnosis of S. kennedyi instead. In view of this, the present study aimed to clarify the identity of this Brazilian population through a reassessment of its specimens and call recordings, together with the examination of data of S. kennedyi from its type locality, and of S. rostratus from northern Venezuela. Acoustic and morphological analyses revealed that specimens from northern Brazil were indeed misidentified as S. rostratus, and hence they were herein reassigned to S. kennedyi. The study therefore demonstrates the occurrence of S. kennedyi in Brazil, extending its distribution ca. 1,120 km east by south from its type locality, and ca. 844 km east-southeast from its easternmost previous record. With this reassessment, a clearer acoustic diagnosis between S. kennedyi and S. rostratus was provided, as well as further data on fine-scale temporal traits of their calls.

Cultural Control of Giant Sugarcane Borer, Telchin licus (Lepidoptera: Castniidae), by Soil Mounding to Impede Adult Emergence

The giant sugarcane borer, Telchin licus (Drury) (Lepidoptera: Castniidae), also known as the banana stem borer, is an economically important pest of sugarcane in eastern Colombia. The presence of larval and pupal stages within stalks makes biological control of this pest difficult, and growers often resort to insecticide applications. Hilling up the soil around the base of plants, or soil mounding, is a cultural practice sometimes used to improve rooting in sugarcane. Because mature larvae cut holes in stalks close to ground level through which they can emerge as an adult, we hypothesized that soil mounding would impede adult emergence, and thus contribute to population reduction. Two experiments were conducted in fields with significant infestations of this pest in Puerto López, Meta, Colombia, during the seasons of adult emergence in this region (Apr–May and Oct–Nov). Manual mounding of soil to a height of 20 cm was tested in the first trial, and mechanized mounding of soil in the second, which also compared 2 mounding heights (10 and 20 cm). In both cases, 2 m row transects of plants were caged to collect emergent adults. Adult emergence was reduced up to 65% in all mounding treatments, whether manual or mechanical, and regardless of mounding height, demonstrating that this cultural practice could be a useful tactic for inclusion in an integrated management program for this pest. However, as with any other cultural practice in pest management, region-wide implementation likely would be required to impact local population densities, and efficacy will depend further on low levels of moth immigration from alternative host plants.

Prospects for using wastewater from a farm for algae cultivation: The case of Eastern Colombia

In recent years, the technical and economic feasibility of using microalgae and cyanobacteria has been explored for the removal and exploitation of domestic, agricultural and industrial residual effluents with high C, N and P compounds content. To contribute to the understanding of the process and its technical viability for microalgae growth, the article discusses monitoring, flow determination, and physicochemical characteristics of two types of effluents generated in an experimental farm located in the east of Colombia, before (R1) and after biological treatment (R2). In general, the results showed the reduction of different parameters, such as total dissolved solids (TDS), hardness, salinity and phosphates after treatment with activated sludge. However, the conductivity value obtained in R1 and R2 showed the presence of a pollutant load. These findings can be attributed to the highest concentration of fats and oils in the water during early hours of the day. Finally, although the concentration of nitrates increased from 46.63 to 225.21 mg∙dm–3 and phosphate decreased slightly from 9.65 to 6.21 mg∙dm–3, no inhibition was generated in the microalgae, as evidenced in the growth of the microalgal biomass in effluents after nitrate and phosphate removal above 80%.