Composting to control the leaf-cutting ant atta cephalotes l. (hymenoptera: formicidae)

Leaf-cutting ants, Atta and Acromyrmex, are the most important defoliating herbivores in the tropics. In this study, field assays were conducted to compare the effects of two non chemical methods on survival and activity of Atta cephalotes (Formicidae: Myrmicinae) nests. A total of 83 A. cephalotes active nests were randomly assigned to one of three treatments: 1) compostable material introduced and processed into the soil of ant nests; 2) conventional mechanical mixing of the ant nests soil; 3) untreated ant nests. After three months the percentages of dead nets were 26.5, 9.63 and 3.61 using manure compost, mechanical, and control, respectively. A repeated measurement analysis of variance showed significant difference between ant colonies for both treatments, composted and mechanical mixing, with respect to the untreated treatment, given the disruption of foraging trails, mound openings, chambers and tunnels. The strongest effect was observed with the compostable material. Based on its effect on A. cephalotes (Formicidae: Myrmicinae) nests and potential soil enrichment, compostable treatment could be a sustainable and ecologically sound management practice if proper conditions are given at the site. Las hormigas cortadoras de hojas, Atta y Acromyrmex, son los herbívoros más importantes en los trópicos. En este estudio se comparan los efectos de dos métodos no químicos sobre la sobrevivencia y actividad de nidos de Atta cephalotes (Formicidae:Myrmicinae). Un total de 83 nidos activos de A. cephalotes fueron asignados de forma aleatoria a uno de tres tratamientos: 1) incorporación de un material compostable al suelo; 2) remoción y mezcla de la capa superficial del suelo (método convencional) y 3) placebo o control (sin tratamiento). Después de tres meses, los porcentajes de nidos eliminados con cada uno de los tratamientos fueron 26,5; 9,6; y 3,6; respectivamente. Un análisis de varianza de medidas repetidas mostró una diferencia significativa entre las colonias de hormigas sometidas a los tratamientos compostado y remoción mecánica en relación con el placebo. Esto debido a la destrucción de las pistas de forrajeo, de las aberturas, cámaras y túneles. Sin embargo, el más fuerte efecto fue observado con el compostado. Basado en estos resultados sobre los nidos de A. cephalotes y su efecto potencial de enriquecer el suelo, el tratamiento compostado puede representar una práctica sustentable y ecológicamente amigable en el control de hormigueros de Atta

Adoption of a surrogate artificial queen in a colony of Atta cephalotes (L.) (Hymenoptera: Formicidae) in Colombia

In nature, Atta cephalotes (L.) is a monogynous species. Each colony has a single, permanent queen fed and protected by thousands of sterile workers. At death the queen colony practically disappears. Recently a colony established eight years in the International Center for Tropical Agriculture (CIAT), Colombia, loses the queen being orphaned by three months. Starting from the idea of whether this colony could take a surrogate queen, we collect a field young nest of A. cephalotes, which donated its queen to the orphan colony. Overall, there was a slight aggression among workers without attacking the surrogate queen, which was adopted by the orphan colony. Five months later, surrogate queen were still alive and there was presence of larvae and pupae. The results show that artificial colony of A. cephalotes, after a period of orphanhood, accept surrogate queen and remain stable and active

Resistance to the Whitefly, Aleurotrachelus socialis, in Wild Populations of Cassava, Manihot Tristis

The levels of resistance in the wild species of cassava, Manihot tristis Muell-Arg. (Malpighiales: Euphorbiaceae), to the whitefly, Aleurotrachelus socialis Bondar (Hemiptera: Alelyrodidae), the most important economic pest in cassava, Manihot esculenta Crantz (Malpighiales: Euphorbiaceae) crops in South America, were estimated under glasshouse conditions. The parameters of the life history of A. socialis were studied on TST-26 and TST-18 accessions of the wild parent and compared with the susceptible (CMC-40) and resistant (MEcu-72) cultivars. The average longevity on the wild accessions (TST-26, 4.1; TST-18, 4.6 days) and oviposition rates (TST-26, 2.0; TST-18, 1.6 eggs/female/2 days) of the A. socialis females were not significantly different from those of MEcu-72 (5.1 days and 3.4 eggs/female/2days). The longevity and oviposition rates on CMC-40 were highest (11 days and 8.6 eggs/female/2days). Analyses of the demographic parameters (Ro, rm; DT) showed a significant impact of the M. tristis accessions on the potential growth of A. socialis. The average survival time of adults that fed on TST-26, TST-18, and MEcu-72 were significantly different from those recorded on the susceptible genotype. Results from this study revealed important levels of resistance to the whitefly A. socialis on the TST-26 and TST-18 accessions due to the marked differences found for longevity and reproduction, which influenced and were consistent with the differences found in the net reproduction rate (Ro), intrinsic growth rate (rm) and population doubling time (DT). The combined effect of these parameters indicated that M. tristis accessions were inappropriate hosts for A. socialis

Nests of Atta cephalotes (HYMENOPTERA: MYRMICINAE) in contrasting coffee management systems in the departament of Cauca, Colombia

El presente estudio se propuso localizar, cuantificar y caracterizar los nidos de hormigas arrieras en dos sistemas cafeteros de manejo contraste en los municipios de Popayán y Cajibío en el Cauca. Para este fin, se seleccionaron ocho cafetales con sombra, ocho cafetales a libre exposición y cuatro fragmentos de bosque. En cada sitio se realizaron recorridos y se ubicaron los nidos activos, en cada uno, se recolectaron e identificaron los individuos de diferentes castas y se midieron los soldados. Se calculó el área de los nidos, el número y tamaño de las pistas de forrajeo y se registraron las plantas defoliadas. Se relacionó el número y área de los nidos con variables ambientales y se correlacionó el tamaño de los soldados con el área de los nidos. Se recolectaron 276 individuos pertenecientes a cephalotes. Se registraron cuatro nidos en fragmentos de bosque, ocho en cafetales con sombra y nueve en cafetales a libre exposición. El área de los nidos varió entre 0,90 y 758,34 m², con pistas de 1 a 32 m de longitud. El área de los nidos en los cafetales a libre exposición presentó diferencias significativas con respecto a los ubicados en cafetales con sombra y fragmentos de bosque, siendo estos últimos los de mayor tamaño. Se encontró una correlación positiva entre el tamaño de los nidos y riqueza arbórea, cobertura de dosel y espesor de hojarasca, mientras que fue inversa con la temperatura ambiente. El ancho de la cabeza se correlacionó de forma positiva con el área de los nidos. Se registraron 32 especies de plantas con signos de defoliación por A. cephalotes, lo que confirma el hábito generalista de esta especie. Se resalta la importancia de mantener especies asociadas al cultivo de café como recursos alternativos y de protección al forrajeo de la hormiga.The aim of the present study was to localize, quantify and characterize the nests of the leaf cutting ants under two contrasting management systems in coffee areas of the municipalities of Popayan and Cajibio, Department of Cauca. Eight shaded coffee plantations, 8 free standing coffee plantations and 4 forest fragments were selected. At each site rounds were made and active search for nests was carried out; in each site individuals from different castes were collected and identified and soldiers were measured. The nests areas were calculated as well as the number and size of the foraging tracks, and the defoliated plants were recorded. The number and area of the nests were related to environmental variables and the size of soldiers in the nest area was correlated. A total of 276 individuals form Atta cephalotes was collected. Four nests were recorded in forest fragments, eight in shaded coffee plantations and nine in free standing coffee plantations. Nest areas varied between 0.90 and 758.34 m², with trails from 1 to 32 m length. The area of the nests located in free standing coffee plantations showed significant differences in relation to nests located in shaded coffee plantations and in forest fragments, the latter being the largest ones. A positive correlation between size of the nests and tree richness, canopy cover and thickness of fallen leaves was found, while it was inversely correlated with room temperature. The width of the head was positively correlated with the area of the nests. A total of 32 plant species with signs of defoliation by A. cephalotes was recorded confirming the general habit of these species. The importance of maintaining species associated to the coffee crop as alternative resources and for the protection of the ant foraging is highlighted

Dípteros asociados a la floración del aguacate <i>Persea americana</i> Mill cv. Hass en Cauca, Colombia

Existe una alta diversidad de insectos asociados a la floración del aguacate. Aunque las abejas son los principales polinizadores del cultivo, especies de distintos gremios tróficos frecuentan sus inflorescencias y poco se conoce sobre su identidad taxonómica. En el municipio de Morales, Cauca, Colombia, se seleccionaron dos parcelas, en las cuales se escogieron aleatoriamente cuatro árboles de aguacate y cada hora, durante 20 minutos, se realizó la captura de insectos con una jama y el registro de su comportamiento en 10 inflorescencias/árbol entre las 07:00-17:00 horas. Se evaluaron semanalmente los periodos de visita a las flores y la carga polínica de los insectos. Las evaluaciones se efectuaron durante dos épocas de floración. Se encontró alta diversidad de insectos, siendo mayor en los dípteros Lucilia eximia, Chrysomya putoria, Palpada scutellaris y Ornidia obesa. Los insectos presentaron picos de visita floral entre las 10:00-11:00 y 14:00-15:00 horas y, aunque con una baja cantidad de polen en sus cuerpos, se observaron colectando néctar, en cópula o posados en las flores. Esta investigación revela que existe una alta diversidad de dípteros asociados a la floración de Persea americana que puede contribuir a la dispersión del polen en los huertos y diversas funciones biológicas

Dípteros asociados a la floración del aguacate Persea americana Mill cv. Hass en Cauca, Colombia

There is a high diversity of insects associated to the flowering of avocado plants. Although bees are the main pollinators of the crop, species of different trophic guilds visit avocado inflorescences, yet little is known about them. In the municipality of Morales, Cauca, Colombia, two plots were selected and four trees were randomly selected from each one. Insects were collected with a net every hour for 20 minutes and the behavior of visiting insects was recorded in 10 inflorescences/tree. Insect collecting and observations were carried between 07:00-17:00 hours. The periods of visit to the flowers and the pollen load of the insects were evaluated weekly. Evaluations were carried out during two flowering periods. A high diversity of species was found associated with avocado inflorescences, being particularly higher in the order Diptera, with species such asLucilia eximia, Chrysomya putoria, Palpada scutellaris and Ornidia obesa. Insect floral visitors presented peaks between 10:00-11:00 and 14:00-15:00 hours. Although a lowamount of pollen on their bodies was observed, insects were collecting nectar, copulating or perched on flowers. This research shows that there is a high diversity of dipteransassociated with the flowering of Persea americana that could contribute to pollen dispersal in orchards and associated biological functions.Existe una alta diversidad de insectos asociados a la floración del aguacate. Aunque las abejas son los principales polinizadores del cultivo, especies de distintos gremios tróficos frecuentan sus inflorescencias y poco se conoce sobre su identidad taxonómica. En el municipio de Morales, Cauca, Colombia, se seleccionaron dos parcelas, en las cuales se escogieron aleatoriamente cuatro árboles de aguacate y cada hora, durante 20 minutos, se realizó la captura de insectos con una jama y el registro de su comportamiento en 10 inflorescencias/árbol entre las 07:00-17:00 horas. Se evaluaron semanalmente los periodos de visita a las flores y la carga polínica de los insectos. Las evaluaciones se efectuaron durante dos épocas de floración. Se encontró alta diversidad de insectos, siendo mayor en los dípteros Lucilia eximia, Chrysomya putoria, Palpada scutellaris y Ornidia obesa. Los insectos presentaron picos de visita floral entre las 10:00-11:00 y 14:00-15:00 horas y, aunque con una baja cantidad de polen en sus cuerpos, se observaron colectando néctar, en cópula o posados en las flores. Esta investigación revela que existe una alta diversidad de dípteros asociados a la floración de Persea americana que puede contribuir a la dispersión del polen en los huertos y diversas funciones biológicas

Rediscovery of Omalodes (Omalodes) fassli Bickhardt, 1911 (Coleoptera: Histeridae) in Colombia and first report of the species on banana crops (Musa paradisiaca)

After 106 years, the presence of Omalodes (Omalodes) fassli in Colombia has been confirmed, and new distributional data for the country has been provided. This is the first report of the species on banana crops (Musa paradisiaca), it highlights its potential role in the control of the banana weevil, a key pest of this crop worldwide.Después de 106 años, se confirma la presencia de Omalodes (Omalodes) fassli en Colombia y se aportan nuevos datos de su distribución para el país. Este representa el primer registro de la especie en cultivos de plátano (Musa paradisiaca) y se destaca su potencial papel como controlador del picudo del plátano, plaga clave de este cultivo en el mundo

Efecto de la exclusión de insectos visitantes florales en el cuajado de frutos de Persea americana (Lauraceae) cv. Hass.

Insects are considered the main carriers of avocado Persea americana cv. Hass. In order to determine the effect of their exclusion in the fruiting of the crop, this research was proposed in two plantations located in Popayán, Cauca, Colombia. In each farm 10 trees were marked and in each tree 20 inflorescences. Three treatments were evaluated: (a) inflorescences exposed to insect activity (control), (b) covering of inflorescences with cloth bags, and (c) application of insecticide only once and covering of inflorescences with cloth bags. The number of fruits set (fructification) differed significantly between treatments and farms, in the treatment with exposed inflorescences there was a fruit set seven (7) times higher with respect to the treatments with covered inflorescences and covered inflorescences + insecticide, which did not present significant statistical differences among them. Between 12-21 fruits / inflorescence are obtained when the insects are allowed access to the flowers, compared to 2-3 fruits / inflorescence when they are excluded. It is concluded that in the pollination of the crop of P. americana cv. Hass intervenes the wind, however insects have a key role as carriers of pollen.Los insectos son considerados los principales portadores de polen del aguacate Persea americana cv. Hass. Con el objetivo de determinar el efecto de su exclusión en la fructificación del cultivo, se planteó esta investigación en dos plantaciones ubicadas en Popayán (Cauca, Colombia). En cada finca se marcaron 10 árboles y en cada árbol 20 inflorescencias. Se evaluaron tres tratamientos: (a) inflorescencias expuestas a la actividad de los insectos (control), (b) cubrimiento de inflorescencias con bolsas de tela, y (c) aplicación de insecticida una sola vez y cubrimiento de inflorescencias con bolsas de tela. El número de frutos cuajados (fructificación) difirió significativamente entre tratamientos y fincas, en el tratamiento con inflorescencias expuestas hubo un cuajado de fruto 7 veces más alto respecto a los tratamientos con inflorescencias cubiertas e inflorescencias cubiertas + insecticida, los cuales no presentaron diferencias estadísticas significativas entre ellos. Se obtienen entre 12- 21 frutos/inflorescencia cuando se permite el acceso de los insectos a las flores, comparado con 2-3 frutos/inflorescencia cuando se excluyen. Se concluye que en la polinización del cultivo de P. americana cv. Hass interviene el viento, sin embargo, los insectos tienen un rol clave como portadores de polen

Study of overall and local electrochemical responses of oxide films grown on CoCr alloy under biological environments

The interaction of the physiological medium and living tissues with the implant surfaces in biological environments is regulated by biopotentials that induce changes in the chemical composition, structure and thickness of the oxide film. In this work, oxide films grown on CoCr alloys at 0.5 V vs Ag/AgCl and 0.7 V vs Ag/AgCl have been characterized through overall and localized electrochemical techniques in a phosphate buffer solution and 0.3% hyaluronic acid. Nanopores of 10–50 nm diameter are homogeneously distributed along the surface in the oxide film formed at 0.7 V vs Ag/AgCl. The distribution of the Constant Phase Element studied by local electrochemical impedance spectroscopy showed a three-dimensional (3D) model on the oxide films grown at 0.5 V vs Ag/AgCl and 0.7 V vs Ag/AgCl. This behaviour is especially noticeable in oxide films grown at 0.7 V vs Ag/AgCl, probably due to surface inhomogeneities, and resistive properties generated by the potentiostatic growth of the oxide film.This work was supported by the Spanish National government [MINECO-MAT2011-29152-C02-01].Peer reviewe