Climate Change Affects Mosquito Behaviour

Changes in climatic factors such as higher temperatures and increased rainfall affect the developmental, behavioural and distribution patterns of insects like mosquitoes.

- Jo Adetunji

These changes have serious implications for the effective control of insect-borne diseases such as malaria.

Worryingly, temperatures across southern Africa are predicted to increase by at least 0.8°C by 2035.

Malaria is currently present in three provinces in South Africa: Limpopo, Mpumalanga and KwaZulu-Natal. Limpopo reports 62% of the local cases, while KwaZulu-Natal reports only 6%. Over the past 50 years annual temperatures in South Africa have been increasing significantly faster than the global average. The increases have been most extreme in Limpopo, where temperatures have risen by an average of 0.12°C every decade. Small annual shifts have big effects. These higher temperatures increase the malaria risk. This is because the malaria mosquito and parasite are happiest at temperatures between 17°C and 35°C. Warmer weather means vector mosquitoes are able to develop faster, invade new locations, and spread vector-borne diseases. In addition, increased rainfall will potentially increase the number of mosquito vector breeding sites. Vector mosquitoes like those that transmit malaria breed in stagnant and temporary bodies of water. Research in Limpopo has shown that heavy rains in spring are usually associated with higher malaria case numbers during summer.