Composition of the entomofauna in Anopheles spp. breeding sites and evaluation of a novel Bacillus thuringiensis var. israelensis-based larvicide against Anopheles darlingi (Diptera: Culicidae) and non-target aquatic insects under simulated field condition

Malaria remains a serious public health problem in the Amazon. The main vector, Anopheles darlingi , uses natural and artificial water bodies as breeding grounds, places that harbor various aquatic insects, which should be considered in control programs. Therefore, the objective of this research was to determine the composition of the aquatic entomofauna associated with Anopheles spp. breeding sites and to evaluate the efficacy of a new Bacillus thuringiensis var. israelensis biolarvicide against An. darlingi , as well as its impact on non-target insects under simulated field conditions. To assess the composition, nine breeding sites were sampled, yielding a total of 27 samples. Bioassays were conducted using An. darlingi larvae and Baetidae nymphs. A total of 13,395 aquatic insect specimens were collected, representing seven orders and 27 families. The highest abundance was recorded in dams (48.9%), and Diptera was the predominant order, with the family Chironomidae standing out. A total of 787 anopheline larvae were collected mostly from natural breeding sites (36.7%) with An. triannulatus being the most abundant species (42.4%). Bioassays demonstrated high efficacy for the biolarvicide after 72 h, with no significant differences between instars. For Baetidae, the survival rate was 81% up to 216 h, with no significant adverse effects. It is concluded that anopheline breeding sites harbor a high richness of non-target insects and that biolarvicide is a promising alternative for vector control, combining high toxicity against the target with environmental safety.