Foraging activity patterns and nest size of Acromyrmex lobicornis (Hymenoptera: Formicidae) in an urban zone of San Luis

Diversos factores pueden influir sobre la actividad de forrajeo de las hormigas cortadoras de hojas. Sin embargo, los factores climáticos, especialmente la temperatura, puede ser considerada uno de los más importantes en regiones templadas. Se midió la actividad de forrajeo y el tamaño de nido en cuatro colonias Acromyrmex lobicornis Emery en la localidad de Juana Koslay, San Luis. La actividad forrajera se determinó a partir del número de hormigas que ingresa al nido cargadas con fragmentos vegetales por unidad de tiempo a lo largo de un año. Se midió temperatura de aire y suelo en cada oportunidad. Para estimar el tamaño del nido, se midió el área de forrajeo, diámetro del túmulo y número de obreras en cada colonia. Se encontraron asociaciones entre la actividad de forrajeo y las temperaturas del aire y del suelo en todos los meses del año, a excepción de febrero, julio y diciembre. Esta asociación fue positiva en los meses de octubre, mayo, junio, agosto y setiembre, pero negativa en los meses de noviembre, enero, marzo y abril. Las colonias mostraron actividad diurna en invierno y nocturna en verano. La temperatura y el tamaño de nido son factores que influyen sobre la actividad de forrajeo de A. lobicornis.Many factors can affect the foraging activity of leaf-cutting ants. However, climatic factors, especially temperature, could be considered the most important in temperate regions. In this work, we measured foraging activity and nest size in four colonies of Acromyrmex lobicornis Emery located in Juana Koslay, San Luis. Foraging activity was determined by the number of ants carrying plant fragments that entered the nest per unit time during a year. In each opportunity air and soil temperature were measured. To estimate nest size we used foraging area, mound diameter and number of workers in each colony Foraging activity and air and soil temperature correlated in every month of the year except February, July and December. However, the correlation was positive during October, May, June, August and September, and negative in November, January, March and April. The nests showed activity all the year, but diurnal in winter and nocturnal in summer. The temperature and the nest size are factors that influence the foraging activity of A. lobicornis.Fil: Jofre, Laura Elizabeth. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas. Area de Zoología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Medina, Ana Irene. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas. Area de Zoología; Argentin

Hongos asociados con dos poblaciones de Acromyrmex lobicornis (Formicidae) de San Luis, Argentina

Fungi associated with two populations of Acromyrmex lobicornis (Formicidae) from San Luis, Argentina. The ant genera Atta and Acromyrmex (Tribe Attini) include the mowers or trimmers of leaves called leaf-cutting ants, which are the only ants that show an obligate dependence of fungal symbionts as a food source. Fragments of plants collected by these ants are used to grow the fungal symbionts, which produce gongylidia for the larvae and queen of the colony to feed on. The aim of this study was to isolate and characterize both, genetically and taxonomically the fungi cultured by two populations of Acromyrmex lobicornis from San Luis province. Samples were collected from the most superficial chambers of the nests and fungal isolates were cultured in malt extract (ME) and potato dextrose agar (PDA) media. The fungal symbiont associated to A. lobicornis nests was identified as Leucoagaricus gongylophorus (Möller) Singer (Holobasidiomycetes, Agaricales) through its morpho-anatomic characteristics and sequencing of ITS1, ITS2 and 5.8S ribosomal gene. Fungal growth in ME was higher than in PDA, and symbiont isolates showed differential growth rates depending on ant populations from where they originated. Fungal symbiont nutritional features and distributional aspects are discussed.Los géneros Atta y Acromyrmex comprenden a las hormigas cortadoras o podadoras de hojas de la tribu Attini, único grupo de hormigas que presenta una dependencia obligada con simbiontes fúngicos como fuente de alimento. Los fragmentos de plantas recolectados por estas hormigas son utilizados para cultivar al simbionte fúngico, el que origina gongilidios de los cuales se alimentan las larvas y la reina de la colonia. El objetivo de este trabajo fue aislar y caracterizar genómica y taxonómicamente los hongos cultivados por dos poblaciones de Acromyrmex lobicornis de la provincia de San Luis. Para ello, se recolectaron muestras del simbionte de las cámaras de cultivo más superficiales de los nidos y se cultivaron en los medios de extracto de malta (EM) y agar papa dextrosa (APD). El simbionte fúngico se identificó como Leucoagaricus gongylophorus (Möller) Singer (Holobasidiomycetes, Agaricales) por sus características morfo-anatómicas en cultivo, las secuencias del gen 5.8S ribosomal y de los espaciadores ITS1 e ITS2. El diámetro de las colonias de los simbiontes fúngicos aislados fue mayor en EM; además, mostraron crecimiento diferencial entre las poblaciones de hormigas de las que fueron aislados. Se discuten posibles implicancias nutricionales y aspectos relacionados con la distribución de los simbiontes aislados.Fil: Lugo, Mónica Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - San Luis. Instituto Multidiciplinario de Investigación Biológica de San Luis; Argentina;Fil: Crespo, Esteban María. Diversidad Vegetal I. Universidad Nacional de San Luis; Argentina;Fil: Cafaro, Matias Jose. Universidad de Puerto Rico; Puerto Rico;Fil: Jofre, Laura Elizabeth. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia; Argentina

The Effect of nest Size and Species Identity on Plant Selection in Acromyrmex Leaf-Cutting Ants

Leaf-cutting ants are key organisms because their role as primary consumers and potential agricultural pests. However, their foraging ecology was mostly studied as response of extrinsic factors such as climate and plant species traits. We evaluated the effects of intrinsic factors (i. e., nest size and species identity) on the foraging behavior in two species of Acromyrmex Mayr leaf-cutting ants. While large and small nests of A. lobicornis Emery showed similar feeding behavior, small nests of A. striatus Roger harvested a greater percent of the plant species available in their foraging area and showed a higher level of selectivity than larger nests. We discussed some probable reasons for this pattern. Our results highlight the relevance of intrinsic factors and species characteristics to explain changes in the foraging ecology of leaf-cutting ants as colony growth.Fil: Jofre, Laura Elizabeth. Universidad Nacional de San Luis; ArgentinaFil: Medina, Ana Irene. Universidad Nacional de San Luis; ArgentinaFil: Farji Brener, Alejandro Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Moglia, Marta Matilde. Universidad Nacional de San Luis; Argentin

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world\u27s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km² resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e., offset) between in-situ soil temperature measurements, based on time series from over 1200 1-km² pixels (summarized from 8500 unique temperature sensors) across all the world’s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in-situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Global maps of soil temperature.

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Melanophryniscus stelzneri (Redbelly Toad) and Leptodactylus mystacinus (Mustached Frog). Interspecific amplexus

Most anurans can be classified as either explosive or prolonged breeders, although these actually represent two ends of a continuum. In general, anurans that inhabit arid or semiarid regions have explosive breeding periods due to the use of ephemeral ponds for reproduction. The genus Melanophryniscus is a putative monophyletic taxon currently represented by 20 species distributed in southern Brazil, southern Bolivia, Paraguay, Uruguay, and central and northern Argentina. Within the genus, M. stelzneri is an endemic species of Sierras Pampeanas from central-western Argentina Its reproduction is explosive and occurs in temporary ponds associated with heavy rains. When heavy rains and high temperatures occur, most species of anurans in the Chaco Serrano show explosive reproduction. This type of reproductive strategy can lead to atypical amplectic behavior including multiple amplexus, same-sex amplexus, and interspecific amplexus. In fact, within the genus Melanophryniscus some cases of atypical reproductive behavior are known, such as interspecific amplexus between different Melanophryniscus species reported by Baldo and Basso. Herein, we report two cases of atypical amplectic behavior in M. stelzneri: interspecific amplexus involving M. stelzneri and Leptodactylus mystacinus, and intraspecific amplexus between two male M. stelzneri.Fil: Bach, Nadia Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Jofre, Laura Elizabeth. Universidad Nacional de San Luis; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pérez Iglesias, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentin

First herpetofauna record of two protected areas of Santiago del Estero province (Argentina)

Dry Chaco ecoregion is one of the largest remnants of dry forest in Latin America and has a very diverse herpetofauna. However, further studies are required for a deep knowledge of its composition and structure. Our objective was to perform an inventory of the herpetofauna in two natural areas of Dry Chaco of Santiago del Estero: Caburé Sur and Parque Provincial Copo. In the two protected areas we recorded 21 and 25 species of anurans and reptiles, respectively. According to the last Argentinean conservation assessment we found one threatened and five vulnerable species of reptiles in both protected areas. The inventory revealed that herpetofauna of the two protected areas of Santiago del Estero contains about 60% of the Dry Chaco herpetofauna. We report the presence of three new species for Santiago del Estero: Kentropyx viridistriga, Teius oculatus and Stenocercus doellojuradoi. We provide new information for future research and conservation actions on this ecoregion.Fil: Pérez Iglesias, Juan Manuel. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jofre, Laura Elizabeth. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas. Área de Zoología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rueda, Marta P.. Universidad Nacional de Santiago del Estero. Facultad de Ciencias Forestales. Instituto de Silvicultura y Manejo de Bosques; Argentin