The Gravitrap, developed by NEA’s Environmental Health Institute (EHI), is designed to attract and trap female Aedes mosquitoes that are looking for sites to lay their eggs. Such mosquitoes are not seeking a blood meal and hence will not bite people. Female mosquitoes attempting to lay their eggs in these containers will be captured and thus prevented from subsequently biting other people. The Gravitrap also traps and prevents the emergence of any mosquitoes from eggs that are laid in the trap. Therefore, Gravitraps themselves do not add to the mosquito population already in the area, but conversely help to reduce the number of mosquitoes emerging from other breeding sites.

Gravitraps, when distributed across an area, help to monitor the Aedes mosquito population in the vicinity. Knowing which Gravitraps are capturing these mosquitoes helps NEA to prioritise its resources by directing its officers to search for and destroy the breeding habitats at locations with higher Aedes mosquito populations. If the Gravitraps are misplaced or toppled, this would disrupt our sentinel network and could cause our officers to search for breeding habitats in the wrong areas, resulting in delays in tackling the dengue problem. We therefore seek the cooperation of the public to not remove or tamper with the Gravitraps.

Gravitraps are usually deployed along the common corridors of HDB residential premises. In January 2020, NEA completed the additional deployment of Gravitraps to private landed estates, complementing those already deployed at HDB estates since 2017. We now have more than 68,000 Gravitraps deployed islandwide, to monitor the Aedes mosquito population in Singapore. NEA officers will check and maintain the Gravitraps regularly, to ensure that they are functioning properly. If members of the public come across Gravitraps that are toppled over, please submit your feedback electronically via the Online Feedback Form or myENV mobile application, so that our officers can follow up.