Effect of agricultural land-use change on ant dominance hierarchy and food preferences in a temperate oak forest

Background The discovery-dominance trade-off is the inverse relationship between the ability of a species to discover resources and the species’ dominance of those resources; a paradigm used to explain species coexistence in ant communities dependent on similar resources. However, factors such as stress (e.g., temperature) or disturbance (e.g., removal of biomass) associated with the change in land use, can modify this trade-off. Here, we aimed to determine the potential effects of land use change on dominance hierarchy, food preferences and on the discovery-dominance trade-off. Methods An experiment with baits was used to investigate the dominance hierarchies of ant communities in a temperate mountain habitat in central Mexico. We evaluated the dominance index (DI), food preferences and discovery-dominance trade-offs of ants inhabiting two types of vegetation: a native oak forest and agricultural land resulting from agricultural land use and grazing. Results The ant communities in both environments were comprised of three species of ants (Monomorium minimum, Myrmica mexicana, and Camponotus picipes pilosulus), four morphospecies (Pheidole sp.1 and Pheidole sp.2, Temnothorax sp. and Lasius sp.) and one genus (Formica spp.). All Formicidae showed values of intermediate to low DI, and this factor did not seem to be influenced by the change in land use. Ants in the modified vegetation (i.e., agricultural land) were found to be numerically greater. Overall, a higher number of visits were registered to the tuna bait, although the duration of foraging events to the honey baits was longer. However, foraging times were dependent on the species considered: the generalized Myrmicinae, M. minimum, the ant species with highest DI, foraged for longer periods of time in the agricultural land and on the tuna bait. Meanwhile, the cold-climate specialist Formica spp., with a lower DI, foraged for longer periods of time in the oak (although not significant) and on the honey bait. We found little evidence of the discovery-dominance trade-off; instead, we found considerable diversity in the strategies used by the different species to access resources. This range of strategies is well represented by the generalized Myrmicinae M. minimum, the cold-climate specialists Formica spp. and Temnothorax sp., and the rare species, as the cold climate specialist Lasius sp. (insinuators). Conclusions Our evaluation shows that transformation of the original habitat does not appear to affect the hierarchical dominance of the ant communities, but it does affect their food preferences. Species with higher DI values such as the generalized Myrmicinae are more skilled at resource acquisition in modified habitats. Our results suggest that change in land use promotes an increase in the diversity of foraging strategies used by different ant species. This diversity may contribute to resource partitioning which favors coexistence

Víctor Rico-Gray (1951-2021): un recorrido por la vida de un gran visionario en la ecología

As a tribute and permanent memory of those of us who were his students, continuing his legacy, in commemoration of his death anniversary, on April 4.Como homenaje y permanente recuerdo de quienes fuimos sus estudiantes, continuando su legado, en conmemoración de su aniversario luctuoso, el día 4 de abril.   &nbsp

Diversity of floral visitors to sympatric Lithophragma species differing in floral morphology

Most coevolving relationships between pairs of species are embedded in a broader multispecific interaction network. The mutualistic interaction between Lithophragma parviflorum (Saxifragaceae) and its pollinating floral parasite Greya politella (Lepidoptera, Prodoxidae) occurs in some communities as a pairwise set apart from most other interactions in those communities. In other communities, however, this pair of species occurs with congeners and with other floral visitors to Lithophragma. We analyzed local and geographic differences in the network formed by interactions between Lithophragma plants and Greya moths in communities containing two Lithophragma species, two Greya species, and floral visitors other than Greya that visit Lithophragma flowers. Our goal was to evaluate if non-Greya visitors were common, if visitor assembly differs between Lithophragma species and populations and if these visitors act as effective pollinators. Sympatric populations of L. heterophyllum and L. parviflorum differ in floral traits that may affect assemblies of floral visitors. Visitation rates by non-Greya floral visitors were low, and the asymptotic number of visitor species was less than 20 species in all populations. Lithophragma species shared some of the visitors, with visitor assemblages differing between sites more for L. heterophyllum than for L. parviflorum. Pollination efficacy experiments showed that most visitors were poor pollinators. Single visits to flowers by this assemblage of species resulted in significantly higher seed set in Lithophragma heterophyllum (30.6 ± 3.9 SE) than in L. parviflorum (4.7 ± 3.4 SE). This difference was consistent between sites, suggesting that these visitors provide a better fit to the floral morphology of L. heterophyllum. Overall, none of the non-Greya visitors appears to be either sufficiently common or efficient as a pollinator to impose strong selection on any of these four Lithophragma populations in comparison with Greya, which occurs within almost all populations of these species throughout their geographic ranges

Diversity of floral visitors to sympatric Lithophragma species differing in floral morphology

Most coevolving relationships between pairs of species are embedded in a broader multispecific interaction network. The mutualistic interaction between Lithophragma parviflorum (Saxifragaceae) and its pollinating floral parasite Greya politella (Lepidoptera, Prodoxidae) occurs in some communities as a pairwise set apart from most other interactions in those communities. In other communities, however, this pair of species occurs with congeners and with other floral visitors to Lithophragma. We analyzed local and geographic differences in the network formed by interactions between Lithophragma plants and Greya moths in communities containing two Lithophragma species, two Greya species, and floral visitors other than Greya that visit Lithophragma flowers. Our goal was to evaluate if non-Greya visitors were common, if visitor assembly differs between Lithophragma species and populations and if these visitors act as effective pollinators. Sympatric populations of L. heterophyllum and L. parviflorum differ in floral traits that may affect assemblies of floral visitors. Visitation rates by non-Greya floral visitors were low, and the asymptotic number of visitor species was less than 20 species in all populations. Lithophragma species shared some of the visitors, with visitor assemblages differing between sites more for L. heterophyllum than for L. parviflorum. Pollination efficacy experiments showed that most visitors were poor pollinators. Single visits to flowers by this assemblage of species resulted in significantly higher seed set in Lithophragma heterophyllum (30.6 ± 3.9 SE) than in L. parviflorum (4.7 ± 3.4 SE). This difference was consistent between sites, suggesting that these visitors provide a better fit to the floral morphology of L. heterophyllum. Overall, none of the non-Greya visitors appears to be either sufficiently common or efficient as a pollinator to impose strong selection on any of these four Lithophragma populations in comparison with Greya, which occurs within almost all populations of these species throughout their geographic ranges

Edificio sub-delegación sur IMSS Puebla Carlos Obregón Santacilia

“Basado en un previo análisis de las subdelegaciones de Puebla, encontramos algunas deficiencias y problemáticas presentes en el Edificio Subdelegación Sur IMSS Puebla, antes de la construcción del Distribuidor Juárez Serdán se tenía una mayor circulación de rutas y una accesibilidad directa al inmueble a pesar de la falta de estacionamiento y actualmente con la reubicación de rutas por la entrada de un nuevo medio de transporte Red Urbana de Transporte Articulado (RUTA), la entrada de este medio de transporte ha cambiado drásticamente el entorno urbano del inmueble. Por ello la elección del tema está dirigida hacia la reubicación del inmueble de la subdelegación sur IMSS Puebla, para encontrar un terreno apto que satisfaga las necesidades de espacio interior, pensado en el trabajador para que sus actividades tengan un resultado favorable de estancia y ofrecer al afiliado una respuesta de movilidad interna óptima y que durante su transcurso por el inmueble sea una experiencia diferente a la que se tiene comúnmente.

Changes in the core species of the ant-plant network of oak forest converted to grassland: replacement of its ant functional groups

Land-use change in terrestrial environments is one of the main threats to biodiversity. The study of ant-plant networks has increased our knowledge of the diversity of interactions and structure of these communities; however, little is known about how land-use change affects ant-plant networks. Here we determine whether the change in land use, from native oak forest to induced grassland, affected the network properties of ant-plant networks in a temperate forest in Mexico. We hypothesize that the disturbed vegetation will be more nested and generalized due to the addition of generalist species to the network. The oak forest network comprises 47 plant species and 11 ant species, while the induced grassland network has 35 and 13, respectively. Floral nectar was the resource used most intensely by the ants in both vegetation types. The ant-plant network of the induced grassland was significantly more nested and generalist than that of the oak forest; however, none of the networks were nested when considering the frequency of interaction. In both vegetation types, the ants were more specialized than the plants, and niche overlap was low. This could be related to the dominant species present in each type of vegetation: Prenolepis imparis in the oak forest and Camponotus rubrithorax in the grassland. The central core of cold climate ant species in the oak forest was replaced by a central core of subordinate Camponotini and tropical specialists in the induced grassland. These results suggest that the increase in nestedness and generalization in the grassland may be related to the loss of the cold climate specialists from the core of the oak forest network. Our findings provide evidence that land-use change increases the level of generalization in the ant-plant interaction networks of temperate forests

Sobrevivencia de Azospirillum brasilense después de aplicar herbicidas en Triticum aestivum L. Var. Altiplano

Herbicides are widely used in agriculture and are applied in various amounts that may directly or indirectly influence on soil microorganisms and their processes. In order to evaluate the survival of inoculated Azospirillum brasilense in the Altiplano variety of wheat to the application of two types of commercial herbicides, an organochlorine and, the other organophosphorus, the present experiment was established in the Ecozone, of the University of the Americas-Puebla, Mexico, under greenhouse conditions in 2009. The seeds were inoculated before planting with Azospirillum brasilense and, the herbicides were applied 40 days after. The treatments were applied: 1) uninoculated plants (absolute control); 2) inoculation with Azospirillun (inoculated control); 3) inoculated with Azospirillum plus herbicide application 2, 4, D, (organochlorine); 4) inoculated with Azospirillum plus glyphosate herbicide application (organophosphate); 5) without inoculation and applying herbicide 2, 4, D; and 6) without inoculation and application of glyphosate, in a completely randomized design with ten replicates. The survival of the bacteria in the root system was recorded through the use of the most probable number technique, recording the plant height and weight. The results indicated that, the two herbicides (2, 4, D and glyphosate),did not significantly affected the population of Azospirillum in the root. Plants inoculated with the bacteria, with or without herbicide treatment showed increased in biomass compared to the non-inoculated plants. Biomass increased with application 2, 4, D.Los herbicidas son ampliamente utilizados en la agricultura y se aplican en diversas cantidades que pueden influir directa o indirectamente en los microorganismos del suelo y sus procesos. Con el objetivo de evaluar la sobrevivencia de Azospirillum brasilense inoculado en la variedad altiplano de trigo a la aplicación de dos tipos de herbicidas comerciales, un organoclorado y otro organofosforado, se estableció el presente experimento en la Ecozona de la Universidad de las Américas-Puebla, México, en condiciones de invernadero en 2009. Las semillas se inocularon antes de la siembra con Azospirillum brasilense y los herbicidas se aplicaron 40 días después. Se establecieron los tratamientos: 1) plantas sin inocular (testigo absoluto); 2) inoculación con Azospirillun (testigo inoculado); 3) inoculación con Azospirillum más aplicación de herbicida 2, 4, D, (organoclorado): 4) inoculación con Azospirillum más aplicación de herbicida glifosato (organofosforado); 5) sin inoculación y aplicación de herbicida 2, 4, D; y 6) sin inoculación y aplicación de glifosato, en un diseño completamente al azar con diez repeticiones. Se registró la sobrevivencia de la bacteria en el sistema radical mediante la técnica número más probable y en la planta se registró su altura y peso. Los resultados indican que los dos herbicidas (2, 4, D y glifosato), no afectaron de manera significativa la población de Azospirillum presente en la raíz. Las plantas inoculadas con la bacteria, con o sin tratamiento de herbicida registraron mayor biomasa en comparación con las plantas sin inocular. La biomasa se incrementó con la aplicación 2, 4,