Adulticidal activity against Stegomyia aegypti ( Diptera: Culicidae ) of three Piper spp

Três espécies de Piper, Piper longum, P. ribesoides e P. sarmentosum, foram selecionadas para investigação da potencialidade contra Stegomyia aegypti adultos, principal vetor de dengue e febre do dengue hemorrágico. Sucessivas extrações por maceração com etanol a 95% mostraram uma porcentagem de extratos etanólicos, derivados de P. longum, P. ribesoides e P. sarmentosum, de 8,89, 3,21 e 5,30% (w/w), respectivamente. Todos os extratos de Piper mostraram atividade adulticida expressiva quando testados contra fêmeas de mosquitos através de aplicação tópica. A suscetibilidade das fêmeas do St. aegypt ao extrato de Piper etanólico foi dose dependente e variou entre as espécies de plantas. O mais elevado efeito adulticida foi demonstrado a partir do P. sarmentosum, seguido pelo P. ribesoides e P. longum, valores LD50 de 0,14, 0,15 e 0,26 µg/fêmea, respectivamente. O potencial destas espécies de Piper, como possíveis mosquiticidas, estabeleceu atividade convincente para futuras pesquisas a fim de desenvolver substâncias naturais para o combate a mosquitos adultos.

Laboratory colonization of Aedes lineatopennis.

Aedes lineatopennis, a species member of the subgenus Neomelaniconion, could be colonized for more than 10 successive generations from 30 egg batches [totally 2,075 (34-98) eggs] of wild-caught females. The oviposited eggs needed to be incubated in a moisture chamber for at least 7 days to complete embryonation and, following immersion in 0.25-2% hay-fermented water, 61-66% of them hatched after hatching stimulation. Larvae were easily reared in 0.25-1% hay-fermented water, with suspended powder of equal weight of wheat germ, dry yeast, and oatmeal provided as food. Larval development was complete after 4-6 days. The pupal stage lasted 3-4 days when nearly all pupae reached the adult stage (87-91%). The adults had to mate artificially, and 5-day-old males proved to be the best age for induced copulation. Three to five-day-old females, which were kept in a paper cup, were fed easily on blood from an anesthetized golden hamster that was placed on the top-screen. The average number of eggs per gravid female was 63.56 +/- 22.93 (22-110). Unfed females and males, which were kept in a paper cup and fed on 5% multivitamin syrup solution, lived up to 43.17 +/- 12.63 (9-69) and 15.90 +/- 7.24 (2-39) days, respectively, in insectarium conditions of 27 +/- 2 degrees C and 70-80% relative humidity.

Intraspecific hybridization of two karyotypic forms of Anopheles vagus (Diptera: Culicidae) and the related egg surface topography.

Hybridization tests of the two karyotypic forms (Form A and B) of laboratory-raised, isolines of Anopheles vagus, were conducted by induced copulation. The results of reciprocal- and back-crosses indicated that they were genetically compatible, providing viable progeny. Comparative egg morphometry and morphology, aided by scanning electron microscopy (SEM), revealed that the eggs of the two karyotypic forms were morphometrically and morphologically similar.