Avaliação da toxicidade de solventes e surfactante sobre os estágios imaturos de Rhipicephalus sanguineus e Amblyomma cajennense (Acari: Ixodidae) e estudos preliminares sobre ectoparasitos de aves silvestres de fragmentos de Mata Atlântica da Zona da Mata de Minas Gerais

Abstract

The present study aimed to evaluate the toxicity of different solvents and of Tween 80 in immature stages of Rhipicephalus sanguineus and in larvae and engorged and non engorged nymphs of Amblyomma cajennense. For non engorged larvae of R. sanguineus it was utilized the larval packet test modified and mortality was evaluated after 24 hours. The same test was adapted for non engorged nymphs of both species and in both assays were tested ethanol, methanol and acetone in its pure concentrations and dimethylsulphoxide and Tween 80 in a concentration of 50μl/ml. For engorged larvae and nymphs it was utilized the immersion test and mortality was available after 15 days. The solvents ethanol, methanol and acetone were testes at concentrations of 50, 250, 500, 750 and 1000 μl/ml, while dimethylsulphoxide and the surfactant Tween were tested at concentrations of 50μl/ml, however, in the assays with A.cajennense engorged stages, the surfactant was added with a concentration of 25μl/ml. Ten repetitions were made for each treatment and the experimental groups were maintained in a BOD incubator (27±1°C e UR>80±10%).For each test it was made a control group with distilled water. For R.. sanguineus acetone showed toxic effects in engorged stages at the higher concentration, ethanol and methanol were toxic at higher concentration only for engorged larvae; to engorged larvae of A. cajennense the ethanol, methanol and acetone were toxic in the higher concentrations and the Tween caused mortality of 52 and 80% of larvae in concentrations of 25 and 50μl/ml respectively, for engorged nymphs, methanol caused a mortality of 17,4 and acetone of 100% when tested in pure concentrations, the tested solvents did not show any effect in engorged nymphs. As a preliminary remark on the presence of ectoparasites in wild birds, 58 birds were examined from 5 families with a prevalence of 15.5% of ectoparasites.