VELOSO FRANCELINO, MÁRCIO R., DE LIMA MENDONÇA, ADRIANA, DO NASCIMENTO, RUTH R., DE MENDONÇA, FERNANDO A. C., DA SILVA, EDLEIDE L., DE FREITAS, MARIA DO ROSÁRIO T., CABRAL JR., CYRO R., DA SILVA, CARLOS EDUARDO, RIBEIRO, JOSÉ H. S., and SANTANA, ANTÔNIO EUZÉBIO G.
Ethological studies are conducted under laboratory conditions using workers of Atta sexdens sexdens and Atta opaciceps collected from field colonies to investigate the mechanisms involved in the alarm response and intra-specific recognition in leaf-cutting ants. Hexane extracts from the heads of gardeners and generalist workers elicit higher levels of alarm response in foragers from the same colony than do mandibular gland extracts from foragers and soldiers, indicating that gardeners, generalists and foragers are primarily responsible for the production of alarm pheromone. Foragers subjected to extracts from non-nestmates exhibit significantly greater alarm responses than are induced by similar extracts derived from nestmate workers, suggesting that the alarm pheromone may have a role in nestmate recognition. [ABSTRACT FROM AUTHOR]
The insecticidal activities of extracts and oils of seventeen medicinal plants of Brazil have been determined using an Aedes aegypti larvicidal bioassay. Oils from Anacardium occidentalis, Copaifera langsdorffii, Carapa guianensis, Cymbopogon winterianus and Ageratum conyzoides showed high activities with LC50 values of 14.5, 41, 57, 98 and 148 microg/l, respectively. The most active ethanolic extract tested was that from the stem of Annona glabra which presented an LC50 value of 27 microg/l. The potential application of cashew nut oil, an industrial by-product with low commercial value, in the control of the vector of dengue and yellow fever, may be proposed.
