Centro de Investigación de la Biodiversidad y Cambio Climático
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Coevolutionary arms race versus host defense chase in a tropical herbivore–plant system

2017 , Endara M.-J. , Coley P.D. , Ghabash G. , Nicholls J.A. , Dexter K.G. , Donoso D.A. , Stone G.N. , Pennington R.T. , Kursar T.A.

Coevolutionary models suggest that herbivores drive diversification and community composition in plants. For herbivores, many questions remain regarding how plant defenses shape host choice and community structure. We addressed these questions using the tree genus Inga and its lepidopteran herbivores in the Amazon. We constructed phylogenies for both plants and insects and quantified host associations and plant defenses. We found that similarity in herbivore assemblages between Inga species was correlated with similarity in defenses. There was no correlation with phylogeny, a result consistent with our observations that the expression of defenses in Inga is independent of phylogeny. Furthermore, host defensive traits explained 40% of herbivore community similarity. Analyses at finer taxonomic scales showed that different lepidopteran clades select hosts based on different defenses, suggesting taxon-specific histories of herbivore–host plant interactions. Finally, we compared the phylogeny and defenses of Inga to phylogenies for the major lepidopteran clades. We found that closely related herbivores fed on Inga with similar defenses rather than on closely related plants. Together, these results suggest that plant defenses might be more evolutionarily labile than the herbivore traits related to host association. Hence, there is an apparent asymmetry in the evolutionary interactions between Inga and its herbivores. Although plants may evolve under selection by herbivores, we hypothesize that herbivores may not show coevolutionary adaptations, but instead “chase” hosts based on the herbivore’s own traits at the time that they encounter a new host, a pattern more consistent with resource tracking than with the arms race model of coevolution. © 2017, National Academy of Sciences. All rights reserved.

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Bothrops atrox from Ecuadorian Amazon: Initial analyses of venoms from individuals

2021 , Patiño R.S.P. , Salazar Valenzuela, David , Medina-Villamizar E. , Mendes B. , Proaño-Bolaños C. , da Silva S.L. , Almeida J.R.

Bothrops atrox is the most clinically relevant snake species within the Amazon region, which includes Ecuadorian territories. It comprises a large distribution, which could contribute to the genetic and venomic variation identified in the species. The high variability and protein isoform diversity of its venom are of medical interest, since it can influence the clinical manifestations caused by envenomation and its treatment. However, in Ecuador there is insufficient information on the diversity of venomic phenotypes, even of relevant species such as B. atrox. Here, we characterized the biochemical and toxicological profiles of the venom of six B. atrox individuals from the Ecuadorian Amazon. Differences in catalytic activities of toxins, elution profiles in liquid chromatography, electrophoretic patterns, and toxic effects among the analyzed samples were identified. Nonetheless, in the preclinical testing of antivenom, two samples from Mera (Pastaza) required a higher dose to achieve total neutralization of lethality and hemorrhage. Taken together, these data highlight the importance of analyzing individual venoms in studies focused on the outcomes of envenoming. © 2021 Elsevier Ltd

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Evolutionary history of CAM photosynthesis in Neotropical Clusia: Insights from genomics, anatomy, physiology and climate

2022 , Luján, M. , Oleas Gallo, Nora Helena , Winter, K.

Clusia is a remarkable genus of Neotropical woody plants as its members engage in either C3 photosynthesis or employ, to varying degrees, crassulacean acid metabolism (CAM) photosynthesis. Information about the evolutionary history of CAM in Clusia is scarce. Restriction site-associated sequencing of 64 species (20% of the genus) provided strong support for most of the previously recognized nine lineages. Ancestral reconstruction using maximum parsimony or maximum likelihood under a one-rate model suggested that CAM evolved at least four times independently from a most recent common ancestor (MRCA) with C3, whereas a maximum likelihood two-rate model suggested that CAM was already present in the MRCA followed by reversions to C3 in several lineages. Phylogenetic generalized least square analysis assessed variation in seven leaf anatomical traits and CAM activity measured as δ13C. Results indicate that CAM is highly correlated with palisade mesophyll layer thickness and cell size. In addition, correlation between 19 bioclimatic variables and δ13C was evaluated. It was found that CAM is positively correlated with habitats with a more severe dry season and greater precipitation seasonality. Since CAM is weakly and/or only periodically expressed in many Clusia spp., and thus not readily reflected in δ13C, future analysis of phylogenetically-informed CAM expression in Clusia must include physiological measurements such as CO2 exchange and/or diel changes in leaf acidity for each species under investigation. © 2021 The Linnean Society of London,.

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Habitat-linked genetic variation supports microgeographic adaptive divergence in an island-endemic bird species

2022 , Cheek, R.G. , Forester, B.R. , Salerno, Patricia E. , Trumbo, D.R. , Langin, K.M. , Chen, N. , Scott Sillett, T. , Morrison, S.A. , Ghalambor, C.K. , Chris Funk, W.

We investigated the potential mechanisms driving habitat-linked genetic divergence within a bird species endemic to a single 250-km2 island. The island scrub-jay (Aphelocoma insularis) exhibits microgeographic divergence in bill morphology across pine–oak ecotones on Santa Cruz Island, California (USA), similar to adaptive differences described in mainland congeners over much larger geographic scales. To test whether individuals exhibit genetic differentiation related to habitat type and divergence in bill length, we genotyped over 3000 single nucleotide polymorphisms in 123 adult island scrub-jay males from across Santa Cruz Island using restriction site-associated DNA sequencing. Neutral landscape genomic analyses revealed that genome-wide genetic differentiation was primarily related to geographic distance and differences in habitat composition. We also found 168 putatively adaptive loci associated with habitat type using multivariate redundancy analysis while controlling for spatial effects. Finally, two genome-wide association analyses revealed a polygenic basis to variation in bill length with multiple loci detected in or near genes known to affect bill morphology in other birds. Our findings support the hypothesis that divergent selection at microgeographic scales can cause adaptive divergence in the presence of ongoing gene flow. © 2022 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.

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Reproductive traits associated with species turnover of amphibians in Amazonia and its Andean slopes

2017 , Jiménez-Robles O. , Guayasamin, Juan M. , Ron S.R. , De la Riva I.

Assembly of ecological communities is important for the conservation of ecosystems, predicting perturbation impacts, and understanding the origin and loss of biodiversity. We tested how amphibian communities are assembled by neutral and niche-based mechanisms, such as habitat filtering. Species richness, β-diversities, and reproductive traits of amphibians were evaluated at local scale in seven habitats at different elevation and disturbance levels in Wisui Biological Station, Morona-Santiago, Ecuador, on the foothills of the Cordillera del Kutukú; and at regional scale using 109 localities across evergreen forests of Amazonia and its Andean slopes (0–3,900 m a.s.l.). At local scale, species composition showed strong differences among habitats, explained mainly by turnover. Reproductive modes occurred differently across habitats (e.g., prevalence of direct developers at high elevation, where breeding in ground level water disappears). At regional scale, elevation was the most important factor explaining the changes in species richness, reproductive trait occurrences, and biotic dissimilarities. Species number in all groups decreased with elevation except for those with lotic tadpoles and terrestrial reproduction stages. Seasonality, annual precipitation, and relative humidity partially explained the occurrence of some reproductive traits. Biotic dissimilarities were also mostly caused by turnover rather than nestedness and were particularly high in montane and foothill sites. Within lowlands, geographic distance explained more variability than elevation. Habitat filtering was supported by the different occurrence of reproductive traits according to elevation, water availability, and breeding microhabitats at both scales, as well as other assembly mechanisms based in biotic interactions at local scale. Human-generated land use changes in Amazonia and its Andean slopes reduce local amphibian biodiversity by alteration of primary forests and loss of their microhabitats and the interaction network that maintains their unique amphibian assemblages with different reproductive strategies. © 2017 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

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On geographic barriers and Pleistocene glaciations: Tracing the diversification of the Russet-crowned Warbler (Myiothlypis coronata) along the Andes

2018 , Prieto-Torres D.A. , Cuervo A.M. , Bonaccorso, Elisa

We studied the phylogeography and plumage variation of the Russet-crowned Warbler (Myiothlypis coronata), from Venezuela to Bolivia, with focus on populations from Ecuador and northern Peru. We analyzed sequences of mitochondrial and nuclear genes, geographic distributions, as well as photographs of specimens deposited at museum collections. Phylogenetic analyses identified three major lineages formed by populations from: Venezuela and Colombia (M. c. regulus), Ecuador and northern Peru (M. elata, M. castaneiceps, M. orientalis, M. c. chapmani), and central Peru and Bolivia (M. c. coronata). We found further population structure within M. c. regulus and M. c. coronata, and population structure and complexity of plumage variation within the Ecuador-northern Peru lineage. Time-calibrated trees estimated that most intraspecific variation originated during the Pleistocene; however, this pattern may not be attributed to an increase in diversification rate during that period. We discuss these results in the context of the importance of geographic-ecological barriers in promoting lineage diversification along the Andes and put forward a preliminary taxonomic proposal for major lineages identified in this study. © 2018 Prieto-Torres et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Trees of Amazonian Ecuador: a taxonomically verified species list with data on abundance and distribution

2019 , Guevara Andino J.E. , Pitman N.C.A. , Ulloa Ulloa C. , Romoleroux K. , Fernández-Fernández D. , Ceron C. , Palacios W. , Neill D.A. , Oleas Gallo, Nora Helena , Rivas Torres G. , Altamirano P. , ter Steege H.

We compiled a data set for all tree species collected to date in lowland Amazonian Ecuador in order to determine the number of tree species in the region. This data set has been extensively verified by taxonomists and is the most comprehensive attempt to evaluate the tree diversity in one of the richest species regions of the Amazon. We used four main sources of data: mounted specimens deposited in Ecuadorian herbaria only, specimen records of a large-scale 1-hectare-plot network (60 plots in total), data from the Missouri Botanical Garden Tropicos® database (MO), and literature sources. The list of 2,296 tree species names we provide in this data set is based on 47,486 herbarium records deposited in the following herbaria: Alfredo Paredes Herbarium (QAP), Catholic University Herbarium (QCA), Herbario Nacional del Ecuador (QCNE), Missouri Botanical Garden (MO), and records from an extensive sampling of 29,768 individuals with diameter at breast height (dbh) ≥10 cm recorded in our plot network. We also provide data for the relative abundance of species, geographic coordinates of specimens deposited in major herbaria around the world, whether the species is native or endemic, current hypothesis of geographic distribution, representative collections, and IUCN threat category for every species recorded to date in Amazonian Ecuador. These data are described in Metadata S1 and can be used for macroecological, evolutionary, or taxonomic studies. There are no copyright restrictions; data are freely available for noncommercial scientific use (CC BY 3.0). Please see Metadata S1 (Class III, Section B.1: Proprietary restrictions) for additional information on usage. © 2019 The Authors. Ecology © 2019 The Ecological Society of America

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Isolation and Characterisation of 11 Microsatellite Loci in the Ecuadorian Hillstar Oreotrochilus chimborazo

2017 , Oleas Gallo, Nora Helena , Harvey N. , Rodríguez-Saltos C.A. , Bonaccorso E.

The Ecuadorian Hillstar Oreotrochilus chimborazo is a high Andean hummingbird that inhabits paramo ecosystems from extreme southern Colombia to southern Ecuador. The species is currently divided into three subspecies that differ in morphology and geographic distribution but no molecular differences have been found between them using mitochondrial markers. The aim of this study was to isolate and test microsatellite loci to further explore possible genetic variability between and within these subspecies. Screening an enriched genomic library of O. chimborazo we obtained eleven polymorphic microsatellite loci. These markers will be used to further elucidate evolutionary patterns in the species.

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Urban soil management in the strategies for adaptation to climate change of cities in the Tropical Andes

2022 , Bonilla Bedoya, Santiago , Ángel Herrera, M. , Vaca, A. , Salazar, L. , Zalakeviciute, R. , Mejía, D. , López-Ulloa, M.

The unique characteristics of a city amplify the impacts of climate change; therefore, urban planning in the 21st century is challenged to apply mitigation and adaptation strategies that ensure the collective well-being. Despite advances in monitoring urban environmental change, research on the application of adaptation-oriented criteria remains a challenge in urban planning in the Global South. This study proposes to include urban land management as a criterion and timely strategy for climate change adaptation in the cities of the Tropical Andes. Here, we estimate the distribution of the soil organic carbon stock (OCS) of the city of Quito (2,815 m.a.s.l.; population 2,011,388; 197.09 km2) in the following three methodological moments: i) field/laboratory: city-wide sampling design established to collect 300 soil samples (0–15 cm) and obtain data on organic carbon (OC) concentrations in addition to 30 samples for bulk density (BD); ii) predictors: geographic, spectral and anthropogenic dimensions established from 17 co-variables; and iii) spatial modeling: simple multiple regression (SMRM) and random forest (RFM) models of organic carbon concentrations and density as well as OCS stock estimation. We found that the spatial modeling techniques were complementary; however, SMRM showed a relatively higher fit both (OC: r2 = 20%, BD: r2 = 16%) when compared to RFM (OC: r2 = 8% and BD: r2 = 5%). Thus, soil carbon stock (0–0.15 m) was estimated with a spatial variation that fluctuated between 9.89 and 21.48 kg/m2; whereas, RFM showed fluctuations between 10.38 and 17.67 kg/m2. We found that spatial predictors (topography, relative humidity, precipitation, temperature) and anthropogenic predictors (population density, roads, vehicle traffic, land cover) positively influence the model, while spatial predictors have little influence and show multicollinearity with relative humidity. Our research suggests that urban land management in the 21st century provides key information for adaptation and mitigation strategies aimed at coping with global and local climate variations in the cities of the Tropical Andes. © 2022 Elsevier B.V.

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Muddy boots beget wisdom: Implications for rare or endangered plant species distribution models

2019 , Oleas Gallo, Nora Helena , Feeley K.J. , Fajardo J. , Meerow A.W. , Gebelein J. , Francisco-Ortega J.

Species distribution models (SDMs) are popular tools for predicting the geographic ranges of species. It is common practice to use georeferenced records obtained from online databases to generate these models. Using three species of Phaedranassa (Amaryllidaceae) from the Northern Andes, we compare the geographic ranges as predicted by SDMs based on online records (after standard data cleaning) with SDMs of these records confirmed through extensive field searches. We also review the identification of herbarium collections. The species' ranges generated with corroborated field records did not agree with the species' ranges based on the online data. Specifically, geographic ranges based on online data were significantly inflated and had significantly different and wider elevational extents compared to the ranges based on verified field records. Our results suggest that to generate accurate predictions of species' ranges, occurrence records need to be carefully evaluated with (1) appropriate filters (e.g., altitude range, ecosystem); (2) taxonomic monographs and/or specialist corroboration; and (3) validation through field searches. This study points out the implications of generating SDMs produced with unverified online records to guide species-specific conservation strategies since inaccurate range predictions can have important consequences when estimating species' extinction risks. © 2019 by the authors.

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