Evaluation of methods for collecting mosquitoes (Culicidae: Diptera) in canopy and ground strata in the Brazilian Savanna.

Abstract

The hand-net is the standard method for capturing mosquitoes with sylvatic diurnal activity in disease outbreaks in Brazil. However, occupational risks and biases related to the collectors´ abilities and attractiveness are important limitations. In this study, we compared hand-nets with automatic traps (CDC) associated to CO2 and BG-Lure®, in the Vassununga State Park, a Brazilian Savanna protection area. The collections carried out over 27 days, on the ground and the forest canopy. A total of 1,555 mosquitoes were obtained in 20 taxa. The diversity index ranged between 1.12 and 1.79 and the dominance index, from 0.22 to 0.40. The dominant species in the ground was Aedes scapularis (46.0%) and in the canopy, Hg. janthinomys/capricornii (31.9%). Haemagogus leucocelaenus was rare (n=2). The hand-net resulted in the greatest diversity and abundance of species in both strata, followed by traps associated with CO2. A low degree of similarity was observed between the hand-net on the ground compared to the other capture methods. The use of BG-Lure® alone resulted in a low number of specimens. In conclusion, the hand-net is still the method of choice for collecting arbovirus vectors in the diurnal period, especially yellow fever vectors.

Where boundaries become bridges: Mosquito community composition, key vectors, and environmental associations at forest edges in the central Brazilian Amazon

“…We sampled deeper into the forest and at a coarser resolution in the present study, where we generally found a peak in richness and diversity towards the edge, which declined beyond 500 m. Species accumulation curves showed that rarer taxa remained to be sampled, particularly at 500 m, although these are less likely to serve as bridge vectors given their relative scarcity. Similar results from other studies highlight the difficulty of sampling mosquito species to saturation at ground level in forested environments [40,41], especially given biases associated with different sampling methods [16,33,42].…”