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

Abstract

Serious concerns have arisen regarding urbanization processes in western Amazônia, which result in the creation of artificial habitats, promoting the colonization of malaria vectors. We used structural equation modelling to investigate direct and indirect effects of forest cover on larval habitats and anopheline assemblages in different seasons. We found 3474 larvae in the dry season and 6603 in the rainy season, totalling ten species and confirming the presence of malaria vectors across all sites. Forest cover had direct and indirect (through limnological variables) effects on the composition of larval anopheline assemblages in the rainy season. However, during the dry season, forest cover directly affected larval distribution and habitat variables (with no indirect affects). Additionally, artificial larval habitats promote ideal conditions for malaria vectors in Amazonia, mainly during the rainy season, with positive consequences for anopheline assemblages. Therefore, the application of integrated management can be carried out during both seasons. However, we suggest that the dry season is the optimal time because larval habitats are more limited, smaller in volume and more accessible for applying vector control techniques.

Oviposition and vertical dispersal ofAedesspecies Meigen 1818 (Diptera: Culicidae) at different heights and seasonal periods in an urban forest fragment in Manaus, Amazonas, Brazil

“…In addition to these, and other biotic and abiotic factors verified in the work of Lau et al (2013) and Jayathilake et al (2015), a general reason for this vertical dispersal of Aedes mosquitoes can be suggested to be the abundance of the population of these vectors in colonized habitats, whether residential or peri-urban. The percentage of forest cover and the seasonal period are indicated as important predictors for the mosquito community in general, with a strong relationship with the vector species (Arcos et al, 2021).…”

“…Therefore, the characteristics of Manaus, such as the proximity of forest environments, with two well-defined climatic seasons (dry and rainy) and high temperatures and humidity, favor the proliferation and survival of Aedes spp. According to Lima et al (2021) and Arcos et al (2021), seasonality and forest cover directly and indirectly influence the mosquito larval community, mainly in the peri-urban area of Manaus.…”

Spatial analyses of Plasmodium knowlesi vectors with reference to control interventions in Malaysia

“…Forest cover effects on anopheline abundances during the dry and wet seasons can be linked to the behavior of adults and larvae formations [ 80 ]. Water quality is influenced by forest cover through shading, organic matter inputs, and erosion processes [ 81 ].…”

Mosquito (Diptera: Culicidae) diversity along a rainy season and edge effects in a riparian forest in Southeastern Brazil

“…Regarding temporal variations, mosquito communities strongly respond to rainfall, exhibiting synchronized or highest activity when there is an increase in precipitation (Arcos et al, 2021; Freire et al, 2021; Steiger, Ritchie, & Laurance, 2016). Even in environments with limited seasonality such as the Amazon rainforest, mosquito species diversity is greater in periods of higher precipitation (Arcos et al, 2021). This seasonal pattern becomes more evident when mosquito diversity is compared between the dry and wet seasons of highly seasonal environments (Afolabi & Aladesanmi, 2018; Freire et al, 2021; Santos et al, 2015).…”

“…This seasonal pattern becomes more evident when mosquito diversity is compared between the dry and wet seasons of highly seasonal environments (Afolabi & Aladesanmi, 2018; Freire et al, 2021; Santos et al, 2015). The greater diversity of mosquito species in the rainy season has been mainly associated with the creation and/or increased availability of breeding sites for larval development (Arcos et al, 2021; La Corte et al, 2019). However, little is known about the temporal dynamics of mosquito community structure and composition throughout the wet season in seasonal ecosystems, such as the Brazilian savanna, known as Cerrado.…”