Effects of diflubenzuron on associated insect fauna with Anopheles(Diptera: Culicidae) in laboratory, partial-field, and field conditions in the Central Amazon

Abstract

This study aimed to analyze the possible effects of diflubenzuron on the associated insect fauna under laboratory, semi-field and field conditions. Laboratory bioassays were performed in aquariums with mortality readings (%) every 24h until 96h, and in semi-fields, insects were kept in basins with readings every 24h for up to 12 days, in triplicates and a control. In the field experiment, a collection was performed before the application of diflubenzuron in ten brick factory pits (25m²) and 15 post-application. The values of LC 50 and LC 90 for Chironomus were 2.77x10-3g/L and 0.86g/L, respectively, and for Buenoa, they were 0.019g/L and 0.92g/L, a strong relationship was observed between mortality and exposure time (r²>0.8) in all concentrations used. In semi-field, similar mean values of emergency inhibition were observed, except for Euthyplociidae, which was more sensitive. There was no significant difference between the data of richness and diversity of aquatic insects in the field experiment, considering an interval of 15 days (p=0.32). Finally, the data suggest that diflubenzuron may have a negative effect on the associated insect fauna, but in the field experiment the environmental conditions of Anopheles breeding sites may have affected its efficiency.

Seasonality modulates the direct and indirect influences of forest cover on larval anopheline assemblages in western Amazônia

“…Forest conditions influence anopheline diversity by different paths, which may alter the strength of their seasonal effects. During the dry season, mosquito survival is also affected by altered microclimate (e.g., lower humidity) 51 and lentic habitats contain less water, increased nutrient concentrations and decreased abundance and richness of mosquitoes 52 , 53 . We observed that rainfall plays an important role in the larval abundance of Anopheles in artificial larval habitats in Manaus.…”

“…Also, increased light and water temperature at the edges favor natural predation and biological control processes from potential fish and macroinvertebrates. The conservation of natural enemies and the use of biotic agents in the population control of vector mosquitoes have been recommended in small and medium-sized natural and artificial breeding sites 19 – 53 . A combination of techniques that shape the important environmental variables for the establishment of these species are essential for vector control.…”