Effect of the chitin synthesis inhibitor triflumuron on the development, viability and reproduction of Aedes aegypti

The control of Aedes aegypti is impaired due to the development of resistance to chemical insecticides. Insect Growth Regulators (IGR) exhibit distinct mechanisms of action and are considered potential vector control alternatives. Studies regarding the effects of sublethal IGR doses on the viability of resulting adults will contribute to eval-uating their impact in the field. We analyzed several aspects of Ae. aegypti adults surviving exposure to a partially lethal dose of triflumuron, a chitin synthesis inhibitor. A highly significant difference in the proportion of males and females was noted in the triflumuron-exposed group (65.0 percent males) compared to the controls (50.2 percent males). Triflumuron affected adult longevity, particularly for females; after 16 days, only 29.2 percent of males and 13.8 percent of females were alive, in contrast with 94 percent survival of the control mosquitoes. The locomotor activity was reduced and the blood-feeding ability of the treated females was also affected (90.4 percent and 48.4 percent of the control and triflumuron-exposed females, respectively, successfully ingested blood). Triflumuron-surviving females ingested roughly 30 percent less blood and laid 25 percent fewer eggs than the control females. The treated males and females exhibited a diminished ability to copulate, resulting in less viable eggs.

Freqüência e distribuição espacial de Aedes aegypti e Aedes albopictus (Diptera, Culicidae) no Rio de Janeiro, Brasil / Frequency and spatial distribution of Aedes aegypti and Aedes albopictus (Diptera, Culicidae) in Rio de Janeiro, Brazil

No presente estudo, procuramos avaliar a freqüência de Aedes aegypti e Ae. albopictus dentro e fora das casas de bairros urbanos, suburbanos e rurais nos municípios de Nova Iguaçu e Rio de Janeiro, Brasil, no período de agosto de 2002 a julho de 2004. A maioria das fêmeas e dos machos de Ae. aegyptifoi capturada em ambientes urbanos (56 por cento) e no intradomicílio (78 por cento), o que demonstra maior freqüência dessa espécie em se abrigar no interior de casas e em áreas de maior concentração populacional humana, caráter que aumentam as chances de seu contato com humanos. Já fêmeas e machos de Ae. albopictus foram mais presentes em áreas rurais (93 por cento) e no peridomicílio (90 por cento), demonstrando maior freqüência em se abrigar em áreas com elevada cobertura vegetal e população humana mais rarefeita, atitude que diminui as suas chances de contato com humanos e, por conseguinte, de veiculação do vírus dengue nessa área.