# Seasonal Dynamics Versus Vertical Stratification of Mosquitoes (Diptera: Culicidae) in an Atlantic Forest Remnant, Brazil: A Focus on the Mansoniini Tribe

## TL;DR

This study explores how mosquitoes, especially the Mansoniini tribe, are distributed vertically and seasonally in a Brazilian Atlantic Forest fragment.

## Contribution

The study provides new insights into the ecology of the underexplored Mansoniini tribe in a biodiverse forest ecosystem.

## Key findings

- No marked vertical segregation was observed in the mosquito community.
- Seasonality strongly influenced the Mansoniini tribe's population structure.
- Coquillettidia fasciolata and Mansonia titillans were the most abundant species captured.

## Abstract

Mosquitoes (Diptera: Culicidae) exhibit vertical stratification patterns in forest environments, a fundamental ecological aspect for understanding niche occupation patterns, host-seeking behavior, and consequently arbovirus transmission mechanisms. Despite the relevance of this topic, available studies mostly focus on genera such as Aedes, Haemagogus, and Sabethes which are traditionally associated with arbovirus transmission. There are still important gaps regarding stratification and seasonality in the Mansoniini tribe, whose biology and epidemiological role remain underexplored, especially in highly biodiverse ecosystems such as the Atlantic Forest. This study evaluated the influence of seasonality and vertical stratification on the mosquito community, with a detailed focus on the Mansoniini tribe, in an Atlantic Forest fragment in Brazil, between May 2023 and December 2024. Captures were performed monthly using CDC light traps positioned at 1.5 m and 10 m heights, and specimens were morphologically identified. A total of 880 mosquitoes from nine genera and 24 species were captured, of which 91 (10.3%) belonged to the Mansoniini tribe. The most abundant species were Coquillettidia fasciolata and Mansonia titillans, recorded in both strata. Our results indicate no marked vertical segregation for the studied mosquito community in this specific location, but a strong influence of seasonality, particularly for the Mansoniini tribe, reinforcing the role of meteorological data on the population structure of these species. These site-specific findings offer a foundational ecological portrait and a robust methodological template for a neglected taxon. They generate critical, testable hypotheses about niche partitioning in fragmented forests and underscore the necessity for broader spatial replication to disentangle the relative influence of seasonal versus vertical drivers in similar ecosystems.