Dados do Trabalho

Título

Evaluation of methods for collecting diurnal Culicidae (Diptera) in canopy and ground strata in Savannah Biome of São Paulo State, Brazil.

Introdução

The hand-net is the standard method for capturing wild arbovirus vector mosquitoes in outbreak investigations of many diseases in Brazil. However, biases related to the collectors‘ abilities and attraction, in addition to the occupational risk, are important limitations to be considered.

Objetivo(s)

In this study, we compared hand-nets with automatic traps (CDC) associated with the chemical attractants CO2 and BG-Lure® to collect diurnal mosquitoes.

Material e Métodos

The studied area was located in the biggest fragment of the Vassununga State Park, in the Savannah Biome, in Santa Rita do Passa Quatro, São Paulo, Brazil. The collections were carried out in 27 days, between Feb 2020 and May 2021, from 9:00 to 16:00h, simultaneously in the ground and canopy strata. For comparison between methods, diversity and abundance indexes and cluster analysis were used.

Resultados e Conclusão

A total of 1,531 mosquitoes were obtained and distributed in 20 taxa. The diversity index ranged between 1.12 (CDC with CO²+BGLure) and 1.79 (hand-net), both in the canopy. And, the dominance index ranged between 0.22 (hand-net), in the canopy and 0.40 (CDC with CO²+BGLure), on the ground. The dominant species in the ground stratum were Aedes scapularis (46.0%) and, Ae. albopictus, Haemagogus janthinomys/capricornii, Psorophora albigenu, and Sabethes albiprivus represented 46.6% of the total captured in the ground. In the canopy, Hg. janthinomys/capricornii was the most frequent (31.9%), while Ae. scapularis, Ps. albigenu, Sa. albiprivus and Sabethes glaucodaemon were subdominants. Haemagogus leucocelaenus was rare (n=2), found only in the ground stratum. A low level of similarity was observed between the hand-net on the ground compared to the other capture methods and stratum. In conclusion, the hand-net method resulted in the greatest richness and abundance of species in both strata followed by traps associated with CO2 (with or without BG-Lure®). And, hand-net is still the method of choice for collecting arbovirus vectors. The use of BG-Lure® alone resulted in a restricted number of specimens. Distinctly from Atlantic Forest Biome, more specimens were collected in the ground stratum, including such as those in the genera Haemagogus and Sabethes. In that sense, further studies are needed to best elucidate vertical distribution patterns in both Biome and alternative kairomones.

Palavras-chave

Diurnal mosquitoes, Kairomones, Canopy stratum, Brazilian Savannah