Eave and swarm collections prove effective for biased captures of male Anopheles gambiae mosquitoes in Uganda

Krystal Birungi,Victor Balyesima,C Matilda Collins,Sylvia Kiwuwa-Muyingo,Jonathan K Kayondo,Danspaid P Mabuka,Elinor W Chemoges,Annet Namukwaya,Frederic Tripet

doi:10.1186/s13071-021-04770-x

Krystal Birungi, Victor Balyesima + Show 7 more

Open Access

https://doi.org/10.1186/s13071-021-04770-x

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Abstract

BackgroundTraditional malaria vector sampling techniques bias collections towards female mosquitoes. Comprehensive understanding of vector dynamics requires balanced vector sampling of both males and females. Male mosquito sampling is also necessary for population size estimations by male-based mark-release-recapture (MRR) studies and for developing innovations in mosquito control, such as the male-targeted sterile insect technique and other genetic modification approaches. This study evaluated a range of collection methods which show promise in providing a more equal, or even male-biased, sex representation in the sample.ResultsSwarms were found at all study sites and were more abundant and larger at the peak of the wet season. Swarm sampling caught the most males, but when man/hour effort was factored in, sampling of eaves by aspiration was the more efficient method and also provided a representative sample of females. Grass-roofed houses were the most productive for eave collections. Overall few mosquitoes were caught with artificial resting traps (clay pots and buckets), although these sampling methods performed better at the start of the wet season than at its peak, possibly because of changes in mosquito ecology and an increased availability of natural resting sites later in the season. Aspiration of bushes was more productive at the peak of the wet season than at the start.ConclusionsThe results of this study demonstrate that eave aspiration was an efficient and useful male mosquito collection method at the study sites and a potentially powerful aid for swarm location and MRR studies. The methods evaluated may together deliver more sex-balanced mosquito captures and can be used in various combinations depending on the aims and ecological parameters of a given study.Graphical

Highlights

Traditional malaria vector sampling techniques bias collections towards female mosquitoes
The mosquito swarm collection method was the most productive male mosquito collection method tested in this study, while house eave aspiration was the most efficient
The clear efficiency of house eave aspiration in delivering a sex-balanced and man–hour efficient catch is extremely useful to the design of mosquito collection experiments

Summary

Introduction

Traditional malaria vector sampling techniques bias collections towards female mosquitoes. Com‐ prehensive understanding of vector dynamics requires balanced vector sampling of both males and females. Entomological surveillance and population studies for malaria control require comprehensive and strategized field collections for sampling mosquito vectors [11]. To effectively sample mosquito populations, different collection methods and equipment are deployed depending on the aim of the study and the type of information/data required. A large body of work on mosquito surveillance has been compiled, emanating from decades of vector research and control efforts, the majority of the trapping techniques currently in use are inherently and explicitly targeted at the capture of females—most likely due to the fact that malaria vector control has focused on the plasmodium-spreading female mosquitoes instead of the males which do not bite

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