Mosquito traps are good tools for surveillance and research
Mosquito traps have been regularly and effectively used for surveillance and research, to monitor the mosquito population, species, etc. The traps can be characterised as:
- Active traps – these rely on visual cues (such as light and colour), olfactory cues (such as carbon dioxide and octenol) or thermal cues (such as temperature and moisture) to lure mosquitoes into the traps; or
- Passive traps – these do not rely on attractants, but merely suck in passing mosquitoes.
Active Traps
Active traps are generally designed to attract and trap female mosquitoes that are either:
- Looking for a site to lay their eggs (oviposition traps); or
- Looking for a blood meal (host-seeking traps).
Oviposition Traps
Oviposition traps capture the eggs laid by female mosquitoes. The eggs are able to develop through the larval and pupal stages, but the emergent adults are unable to escape through the wire mesh and thus drown. A large number of such traps must be deployed, as Aedes mosquitoes skip-oviposit and lay their eggs at many different sites.
Host-seeking Traps
Female mosquitoes bite humans and animals (hosts) and blood feed, as they need the protein from blood for development of their eggs. Host-seeking female mosquitoes are attracted to: carbon dioxide (CO2), lactic acid, octenol, light, colour, movement, temperature and moisture. Host-seeking traps are therefore designed to mimic these attractive characteristics of the host, and thus lure the female mosquitoes into the traps. Some of the host-seeking traps commonly used for surveillance and research are listed below.
Passive Traps
Passive traps do not rely on attractants to lure mosquitoes. These traps collect mosquitoes that happen to fly past at close range. An example of a passive trap is the fan-based trap.
Fan-based Trap
Fan-based traps do not require chemical attractants or artificial baits. The design typically comprises a mesh attached to the front of a fan, which is then placed in an area where mosquitoes are attracted (e.g. where people congregate). Mosquitoes are drawn into and trapped in a bag, which is usually emptied once a week.
