# Abundance, Diversity and Phenology of Mosquito Larvae in a Highly Anthropized Wetland: Health and Management Implications of Gándaras de Budiño (NW Spain)

## TL;DR

This study examines mosquito larvae in a wetland in Spain, finding that certain species pose a risk for spreading diseases like West Nile virus.

## Contribution

The study identifies Culex pipiens s.l. and Culex torrentium as key mosquito species with high potential for West Nile virus transmission in a human-impacted wetland.

## Key findings

- Culex pipiens s.l. and Culex torrentium were the most abundant species with high disease transmission potential.
- Temporary and polluted water bodies, along with spring and summer seasons, are linked to increased larval activity.
- Mosquito abundance and diversity are positively correlated with temperature and negatively with humidity.

## Abstract

Because of their role as vectors of diseases, the presence of mosquitoes in wetlands often discourages their protection and conservation. The Gándaras de Budiño (Galicia, northwestern Spain) is a natural wetland highly damaged by the activity of a large industrial estate. The gathering in the same area of human hosts and migratory birds susceptible to carrying diseases such as West Nile virus (WNV) makes it necessary to determine the epidemiological risk of the wetland by studying the abundance, diversity and phenology of its culicid fauna. The field research was conducted in 11 water bodies sampled approximately every 15 days between January and December 2022 using the standardized dipping technique to capture mosquito larvae. A total of 766 specimens belonging to 11 species of the genus Culex (57%), Culiseta (30%) and Anopheles (13%) were identified, though the isolated observation of adult specimens of Coquillettidia and Aedes lead to the determination of eight functional groups. Mosquito abundance and diversity were significantly higher in temporary water bodies and spring season (with a median of 1–2 species more). Generalized linear mixed models (GLMM) revealed that both larval abundance and species richness were positively related with maximum ambient temperature and negatively with the mean relative humidity of the 15 days prior to the sampling date. Although almost all functional groups contain some mosquito capable of transmitting diseases, only Cx. pipiens s.l. (N = 287, 37.5%) and Cx. torrentium (N = 34, 4.4%) represent an emerging risk in the wetland due to their high competence to transmit WNV. Temporary and polluted waters were identified as the main breeding sites of these species, while spring and summer were the period of their major larval activity. The protection and proper management of natural wetlands not only favor the conservation of biodiversity, but is consistent with the prevention and control of mosquito‐borne diseases.

The natural and anthropized wetland of Gándaras de Budiño (Galicia, Spain) hosts a great number of mosquito species.
Culex pipiens
s.l. and Culex torrentium pose an emerging risk for West Nile virus transmission. The temporary and polluted waters, as well as the summer and spring seasons, favor the larval proliferation of these vectors.