The potential for indirect effects between co-flowering plants via shared pollinators depends on resource abundance, accessibility and relatedness

Co-flowering plant species commonly share flower visitors, and thus have the potential to influence each other's pollination. In this study we analysed 750 quantitative plant–pollinator networks from 28 studies representing diverse biomes worldwide. We show that the potential for one plant species to influence another indirectly via shared pollinators was greater for plants whose resources were more abundant (higher floral unit number and nectar sugar content) and more accessible. The potential indirect influence was also stronger between phylogenetically closer plant species and was independent of plant geographic origin (native vs. non-native). The positive effect of nectar sugar content and phylogenetic proximity was much more accentuated for bees than for other groups. Consequently, the impact of these factors depends on the pollination mode of plants, e.g. bee or fly pollinated. Our findings may help predict which plant species have the greatest importance in the functioning of plant–pollination networks.Fil: Chacoff, Natacha Paola. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; Argentin

Plant–pollinator interactions between generalists persist over time and space

Generalist species are the linchpins of networks, as they are important for maintaining network structure and function. Previous studies have shown that interactions between generalists tend to occur consistently across years and sites. However, the link between temporal and spatial interaction persistence across scales remains unclear. To address this gap, we collected data on plant–pollinator interactions throughout the flowering period for 5 yr across six plots in a subalpine meadow in the Rocky Mountains. We found that interactions between generalists tended to persist more in time and space such that interactions near the network core were more frequently recorded across years, within seasons, and among plots. We posit that species' tolerance of environmental variation across time and space plays a key role in generalization by regulating spatiotemporal overlap with interaction partners. Our results imply a role of spatiotemporal environmental variation in organizing species interactions, marrying niche concepts that emphasize species environmental constraints and their community role.Fil: Resasco, Julian. State University of Colorado at Boulder; Estados UnidosFil: Chacoff, Natacha Paola. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Vazquez, Diego P.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentin

Influence of the invasion of Ligustrum lucidum (Oleaceae) on liana community in sierra de San Javier (Tucumán - Argentina)

En la sierra de San Javier (Tucumán, Argentina) se presentan bosques secundarios nativos e invadidos, estos últimos dominados por Ligustrum lucidum, que afecta la biodiversidad nativa. Analizamos la influencia del bosque dominado por L. lucidum sobre las comunidades de lianas en comparación con bosques secundarios nativos sin dominancia de especies exóticas. Los bosques fueron comparados en abundancia, composición, modalidades de trepado y distribución de clases de tamaños de los tallos de lianas. Para ello se establecieron un total de 10 cuadrantes en el sector pedemontano de yungas de la sierra de San Javier en los cuales se midió, identificó y relevó los tallos de lianas ≥ a 0.5 cm y los árboles ≥ a 10 cm en diámetro a la altura del pecho. El bosque nativo presentó cuatro veces mayor abundancia y mayor riqueza de tallos de lianas en comparación con el bosque invadido. Los individuos de L. lucidum hospedaron tallos de lianas en muy baja abundancia y en el bosque dominado por esta especie exótica los hospedadores de lianas fueron principalmente árboles nativos. Además de no constituir soportes adecuados de lianas, se manifiesta una influencia indirecta a través de la exclusión de las especies de árboles nativos que las hospedan.Native and invaded secondary forests are present in sierra de San Javier, the latter dominated by Ligustrum lucidum, which exerts an influence on native biodiversity. We analyzed the influence of the forest dominated by L. lucidum over liana communities compared to native secondary forests without dominance of exotic species. Forests were compared in abundance, composition, climbing mechanisms and distribution in size classes of liana stems. For this, liana stems ≥ 0.5 cm and the trees ≥ 10 cm in diameter at height breast, were measured, identified and surveyed in 10 plots located in the yungas piedmont of sierra de San Javier. Native forests had four times more abundance and richness of liana stems than invaded forest of L. lucidum. Individual trees of L. lucidum hosted liana stems in very low abundance, and in the forest dominated by this exotic species, the liana hosts were mainly native trees. Besides the fact that they do not constitute suitable hosts for lianas, they have an indirect influence through the exclusion of native host trees of lianas.Fil: Ceballos, Sergio Javier. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Malizia, Agustina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chacoff, Natacha Paola. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Pérdida de semillas en fase de pre-dispersión en dos especies de Prosopis (Fabacea: Mimosoidea) del Desierto del Monte, Argentina

Los filtros impuestos sobre las semillas en la fase pre-dispersiva pueden alterar su probabilidad de ser dispersadas. Evaluamos la pérdida de semillas debido a la depredación por insectos y aborción durante la etapa predispersiva en dos especies: Prosopis flexuosa y P. chilensis. El estudio se realizó en dos áreas protegidas del Desierto del Monte. Colectamos frutos de ambas especies de Prosopis a partir de individuos adultos de dos parcelas y en dos años. Las muestras se colocaron en frascos de PVC transparentes almacenados en laboratorio a una temperatura estable (25 °C) y fotoperíodo natural durante 50 días, para determinar la emergencia de los insectos. Luego se abrieron los frutos y se examinó cada semilla para registrar su condición. La pérdida total de semillas fue del 32% en P. flexuosa y del 21% en P. chilensis. La depredación de semillas por insectos fue la fuente principal de pérdida de semillas (19% en P. flexuosa y del 14% en P. chilensis). Los depredadores más importantes fueron Apion sp. (Brentidae: Apioninae) en P. flexuosa, y brúquidos de distintas especies (Chrysomelidae: Bruchinae) en P. chilensis. Algunos brúquidos depredan la semilla y emergen por un pequeño orificio al completar su ciclo, mientras que otros permanecen en el interior de la semilla (41% en P. flexuosa y del 49% en P. chilensis del total de semillas depredadas por brúquidos). La aborción fue la segunda fuente de pérdida predispersiva de semillas, en especial para P. flexuosa, aunque aún se desconocen sus causas. Mostramos y discutimos el alcance de una metodología para la estimación de depredación pre-dispersión, que considera la inclusión de los estadios inmaduros de brúquidos que no emergen de la semilla. La pérdida de semillas pre-dispersión por insectos y aborción, representan un filtro ecológico que podría limitar la cantidad de semillas disponibles para la dispersión y posterior establecimiento de estas especies. Comprender el proceso de pérdida de semillas puede contribuir a conocer y predecir la dinámica poblacional de Prosopis, revelando los mecanismos naturales de regeneración para la recuperación de los bosques.Pre-dispersal filters imposed on the seed stage can alter the likelihood of seed dispersal. We evaluate pre-dispersal seed loss due to predation by insects and abortion in Prosopis flexuosa and P. chilensis. This study was conducted in two protected areas in the Monte Desert. We collected P. flexuosa and P. chilensis fruits from different trees, from two plots and two years. Samples were maintained for 50 days in translucent PVC bo�les stored in a laboratory under stable temperature (25 °C) and natural photoperiod, awaiting the emergence of insects. Then we opened the fruits and individually examined all seeds to determine their condition. We found that total pre-dispersal seed loss was 32% in P. flexuosa and 21% in P. chilensis. Seed predation by insects was the major source of pre-dispersal seed loss (19% in P. flexuosa and 14% in P. chilensis). The main seed predator was the apionid weevil (Brentidae: Apioninae) in P. flexuosa, and bruchid beetles (Chrysomelidae: Bruchinae) in P. chilensis. Some bruchid beetles prey upon seeds, completing their life cycle, whereas others remain inside seeds (41% in P. flexuosa and 49% in P. chilensis, of total seed damaged by bruchid beetles). Seed abortion was another important source of seed loss, especially for P. flexuosa, but its cause still remains unknown. We show and discuss the extent of a proposed methodology to account for pre-dispersal seed predation that includes the immature stages of non-emergent bruchid. Pre-dispersal seed loss by insects and abortion represent an ecological filter that limits the amount of seeds available for dispersal and establishment of these species. Understanding seed loss process may contribute to know and predict Prosopis population dynamics, revealing the natural regeneration mechanisms to forest recovery.Fil: Velez, Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Chacoff, Natacha Paola. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Campos, Claudia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentin

Macroinvertebrates and Fishes as Bioindicators of Stream Water Pollution

Freshwater ecosystems worldwide have been progressively deteriorated during the past decades due to an increasing human pressure that has lead to a decrease in aquatic biodiversity. Among the human activities of high impact on freshwater ecosystems is the land-use change, principally from native forests to agriculture. To evaluate the impacts of human activities on water quality, a traditional approach has considered the use of single physical-chemical parameters. However, this approach may be insufficient to fully assess the impact of these human activities on freshwaters. Therefore, there is a need for alternative tools such as the indices of biotic integrity that may provide a complement to traditional approaches. In the literature, there are several examples of biotic indicators that have shown promising results in evaluating water quality including the use of macroinvertebrates and fish diets. Here, we provide a review of the indicators of biotic integrity that included fish assemblages as well as macroinvertebrates as bioindicators. We identify pros and cons of using aquatic communities as indicators of water quality. Finally, we develop a procedure that combines fish and macroinvertebrate assemblages as bioindicators and discuss their effectiveness using illustrative examples from streams under several agricultural uses in the Mediterranean region of Chile

Rareness and specialization in plant-pollinator networks

Most rare species appear to be specialists in plant-pollinator networks. This observation could result either from real ecological processes or from sampling artifacts. Several methods have been proposed to overcome these artifacts, but they have the limitation of being based on visitation data, causing interactions involving rare visitor species to remain undersampled. We propose the analysis of food composition in bee trap nests to assess the reliability of network specialization estimates. We compared data from a plant-pollinator network in the Monte Desert of Villavicencio Nature Reserve, Argentina, sampled by visit observation, and data from trap nests sampled at the same time and location. Our study shows that trap nest sampling was good for estimating rare species degree. The rare species in the networks appear to be more specialized than they really are, and the bias in the estimation of the species degree increases with the rareness. The low species degree of these rare species in the visitation networks results from insufficient sampling of the rare interactions, which could have important consequences for network structure. © 2011 by the Ecological Society of America.Fil: Dorado, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Vázquez, Diego Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Stevani, Erica Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Chacoff, Natacha Paola. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentin

Using a sentinel colony of Apis mellifera (Hymenoptera: Apidae) to assess pesticides and food sources

Las poblaciones de abejas melíferas están disminuyendo, como ocurre con otros polinizadores. Una de las causas sugeridas de este declive es el impacto de los pesti- cidas. Para mejorar la salud de las abejas, se pueden monitorear los pesticidas y las fuentes de alimentación mediante colmenas centinela, dado que las abejas pecorean en un radio de 2,5 km alrededor de la colmena. Extrajimos 20 (veinte) abejas, así como muestras de cera, miel y polen de una colmena centinela. Se detectaron seis plaguicidas en las muestras, excepto en la miel. Todos los plaguicidas detectados en la colmena centinela están prohibidos en Argentina. Se detectaron ocho familias y géneros de plantas diferentes en las muestras de miel y polen. Nuestro trabajo sugiere que el monitoreo de plaguicidas con colmenas centinela será útil para mejorar las prácticas agrícolas en la región.Honey bee populations are declining as occurs with other pollinators. One suggested cause of this decline is the impact of pesticides. To improve bees’ health, pesticides and food sources may be monitored using sentinel hives, given that bees forage in a 2.5 km radius around the hive. We extracted 20 (twenty) bees, as well as samples of wax, honey and pollen from a sentinel hive. Six pesticides were detected in the samples, except for the honey. All detected pesticides in the sentinel hive are prohibited in Argentina. Eight different plant families and genera were detected in the honey and pollen samples. Our work suggests that monitoring pesticides with sentinel beehives will be useful to improve agricultural practices in the region.Fil: Geria Reines, Martin. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Chacoff, Natacha Paola. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Sosa, Alexis. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Galindo Cardona, Alberto. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Native pollinators increase fruit set while honeybees decrease the quality of mandarins in family farms

Family farms can benefit from the presence of a diverse set of native pollinators and associated pollination services. In the present study we assessed the effect of flower visitor richness and visitation rate by honeybees and native insects on mandarin production (Citrus reticulata `Criolla´), in ten citrus family farms located in the Dry Chaco region of northwest Argentina. An exclusion experiment was conducted to explore how pollinators influence the fruit set and quality of `Criolla´ mandarin. The influence of features such as local richness and abundance of flowering plants, farm size, and surrounding natural/semi-natural habitats in the diversity of flower visitors was also evaluated. Fruit set in open pollination branches was three times higher than in bagged branches, where flower visitors were excluded. Moreover, the mandarin fruit set increased with a higher native visitation rate, and mandarin quality (fruit weight and size) decreased with a higher honeybee visitation rate. Flower visitor diversity was higher in farmlands with a greater proportion of surrounding natural and semi-natural habitats. Our results demonstrate the negative effects of excessive honeybee visitation on citrus fruit quality and highlight the importance of native pollinators and natural habitat conservation to increase the fruit set and quality of mandarin in family farms.Fil: Monasterolo, Marcos. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Centro Regional de Energia y Ambiente Para El Desarrollo Sustentable. - Universidad Nacional de Catamarca. Centro Regional de Energia y Ambiente Para El Desarrollo Sustentable.; ArgentinaFil: Chacoff, Natacha Paola. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Segura, Angel David. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Centro Regional de Energia y Ambiente Para El Desarrollo Sustentable. - Universidad Nacional de Catamarca. Centro Regional de Energia y Ambiente Para El Desarrollo Sustentable.; ArgentinaFil: Benavídez, Analía. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Centro Regional de Energia y Ambiente Para El Desarrollo Sustentable. - Universidad Nacional de Catamarca. Centro Regional de Energia y Ambiente Para El Desarrollo Sustentable.; ArgentinaFil: Schliserman, Pablo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Centro Regional de Energia y Ambiente Para El Desarrollo Sustentable. - Universidad Nacional de Catamarca. Centro Regional de Energia y Ambiente Para El Desarrollo Sustentable.; Argentin

Comparative pan-genome analysis of Piscirickettsia salmonis reveals genomic divergences within genogroups

Indexación: Scopus.Piscirickettsia salmonis is the etiological agent of salmonid rickettsial septicemia, a disease that seriously affects the salmonid industry. Despite efforts to genomically characterize P. salmonis, functional information on the life cycle, pathogenesis mechanisms, diagnosis, treatment, and control of this fish pathogen remain lacking. To address this knowledge gap, the present study conducted an in silico pan-genome analysis of 19 P. salmonis strains from distinct geographic locations and genogroups. Results revealed an expected open pan-genome of 3,463 genes and a core-genome of 1,732 genes. Two marked genogroups were identified, as confirmed by phylogenetic and phylogenomic relationships to the LF-89 and EM-90 reference strains, as well as by assessments of genomic structures. Different structural configurations were found for the six identified copies of the ribosomal operon in the P. salmonis genome, indicating translocation throughout the genetic material. Chromosomal divergences in genomic localization and quantity of genetic cassettes were also found for the Dot/Icm type IVB secretion system. To determine divergences between core-genomes, additional pan-genome descriptions were compiled for the so-termed LF and EM genogroups. Open pan-genomes composed of 2,924 and 2,778 genes and core-genomes composed of 2,170 and 2,228 genes were respectively found for the LF and EM genogroups. The core-genomes were functionally annotated using the Gene Ontology, KEGG, and Virulence Factor databases, revealing the presence of several shared groups of genes related to basic function of intracellular survival and bacterial pathogenesis. Additionally, the specific pan-genomes for the LF and EM genogroups were defined, resulting in the identification of 148 and 273 exclusive proteins, respectively. Notably, specific virulence factors linked to adherence, colonization, invasion factors, and endotoxins were established. The obtained data suggest that these genes could be directly associated with inter-genogroup differences in pathogenesis and host-pathogen interactions, information that could be useful in designing novel strategies for diagnosing and controlling P. salmonis infection. © 2017 Nourdin-Galindo, Sánchez, Molina, Espinoza-Rojas, Oliver, Ruiz, Vargas-Chacoff, Cárcamo, Figueroa, Mancilla, Maracaja-Coutinho and Yañez.https://www.frontiersin.org/articles/10.3389/fcimb.2017.00459/ful