Toxicological and histopathological effects of hydramethylnon on Atta sexdens rubropilosa (Hymenoptera: Formicidae) workers

The leaf-cut ants are important agricultural pest, because they can cause intense defoliation in plants and destroy large areas cultivated. Although there are several works for the control of these insects by examining the toxicity of natural chemical compounds on various species of ants, few are focused on analyses of morphological changes caused in the affected organs. The aim of this study was to evaluate the effects of hydramethylnon on Atta sexdens rubropilosa workers through toxicological bioassays and morphological analysis of the post-pharyngeal glands, midgut, and Malpighian tubules of these ants. Hydramethylnon dissolved either in acetone (HA) or in a mixture of acetone and soy oil (HAO) was added to the artificial diet at a concentration of 200 μg/mL. The workers fed daily with the diet containing hydramethylnon showed higher mortality than the controls, especially when HAO was used. Moreover, light and electron microscopy revealed morphological alterations in the midgut and Malpighian tubules of workers treated with HA, whereas alterations of the post-pharyngeal glands were observed in the HAO-treated group. These results indicated that the presence of soy oil provided an alternate route for the ingestion of the formicide's active ingredient and corroborated previous studies that suggested a role for the post-pharyngeal glands in lipid metabolism. Our findings suggest that the oil may carry hydramethylnon to the gland lumen, resulting in lower quantity of the active ingredient in the intestinal lumen and Malpighian tubules that explains the lower degree of morphological alterations in these structures in the workers treated with HAO. These results may provide insight into the toxicological effects of hydramethylnon on leaf-cutting ants and the use of vegetable oil as an adjuvant in baits to control ants. © 2012 Elsevier Ltd.

Comparative study of intramandibular glands of workers, queens and males of stingless bee Scaptotrigona postica Latreille (Hymenoptera: Meliponini)

The mandibles of bees contain two types of tegumental glands whose function is not clear, despite the hypotheses put forward by several researchers. Although these glands have been found in all the bee species studied so far, observations have been confined mostly to workers of eusocial species in the forager phase. The work reported here involved a study of the morphology of the glands of newly emerged, nurse and forager workers, virgin and fecundated queens, and newly emerged and sexually mature males of Scaptotrigona postica, seeking to identify changes that may be linked to the bees life phase. Our findings indicate that the two types of glands are present in the species but not in all life phases or individual classes. The glands consisting of class I cells, the epithelial glands are present only in forager workers and fecundated queens. Glands of type III cells were studied in detail, and gland size was estimated from histological sections. The degree of development of the glands varies according to individual classes and life phases, suggesting different functions during the individuals life and from one individual to another. © Koninklijke Brill NV, Leiden, 2012.

Resolución 3: Establecimiento de un Grupo Mixto de Trabajo con la Organización de Alimentación y Agricultura = Resolution 3: Establishment of a Joint Working Party with the Food and Agriculture Organization = Résolution 3: Création d'un groupe mixte de travail avec l'Organisation pour l'Alimentation et l'Agriculture

El símbolo E/840/Rev.1 corresponde a la edición bilingüe inglés/francés publicada en 1953

Temporal polyethism and life expectancy of workers in the eusocial wasp polistes canadensis canadensis Linnaeus (Hymenoptera: Vespidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Taller sobre programas para trabajadores migratorios temporales: compilación de trabajos = Workshop on temporary migrant workers programs: compilation of works

Incluye Bibliografía

Women workers in the Caribbean: a selection of ECLAC research

Includes bibliography

Interesting proposals of the AMP Working Party on a new pricing system

Informa acerca de las conclusiones y propuestas del Grupo de Trabajo encargado de revisar el protocolo de comercializacion agricola (AMP)

People and workers in Latin America: simulation experiments with population and the labour force in selected countries

Includes bibliography

Anônimas da história: relações de trabalho e atuação política de sapateiras entre as décadas de 1950 e 1980 (Franca-SP)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Operários e camponeses: a repercussão da Revolução Mexicana na imprensa operária brasileira (1910-1920)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)