A technique for preparing polytene chromosomes from Aedes aegypti (Diptera, Culicinae).

Polytene chromosome preparations were obtained from larval, pupal and adult female Malpighian tubules of Aedes aegypti. The Malpighian tubules of the pupae (0-4 h old) from larvae reared at 20 C provided the best cytogenetic analysis. The interaction of nucleic acids and proteins that influence the spreading of the chromosomes could be reduced with the preparation technique of the sheets submitted to a stronger treatment starting with the hypotony of tissue and successive bathings with acetic acid.

Malpighian tubule polytene chromosomes of Culex quinquefasciatus (Diptera, Culicinae).

Dipteran polytene chromosomes provide an excellent model for understanding in species complexes, as well as for structural and functional cytogenetics. The status of species in the Culex pipiens complex is controversial and the use of polytene chromosomes for cytogenetic analysis in the subfamily Culicinae has been difficult because of methodological problems. In this study, Malpighian tubule polytene chromosomes were obtained from young (0 to 12 h, 20 C) and old (20 to 42 h, 28 C) laboratory-bred C.

Experimental infection of Aedes albopictus (Diptera: Culicidae) Larvae with the Xiphidiocercariae of a hematolechid.

Aedes albopictus larvae were exposed, either individually or in groups, to different concentrations of xiphidiocercariae of Haematoloechus sp. for parasitological studies. It was observed the acute lethal effect and some aspects of the host-parasite relationship, such as delay or progress in the host life cycle, the number and location of the metacercariae in the host, adult host malformations and the amount of metacercariae required to cause death.

[Insecticide resistance in Simulium populations (Diptera, Simuliidae)].

Populations of Simulium (Chirostilbia) pertinax Kollar, 1832 from Southern and Southeastern States of Brazil were analyzed for temephos susceptibility considering control historical information and possible resistance. In situ bioassays were carried out for populations from the states of Paraná (Tibaji and Rolândia), Rio de Janeiro (Muriqui) and São Paulo (Barra do Una, Ilhabela and Morungaba). The populations were characterized as susceptible (S) or resistant (R) by submitting larvae in the last instars to an operational concentration (0.