UK Health Security Agency 1 article published in JoVE Biology Determining Temperature Preference of Mosquitoes and Other Ectotherms Amirah Haziqah-Rashid1, Kinga Stobierska1, Lorna Glenn1, Soeren Metelmann1,2, Ken Sherlock3, Ewa Chrostek1, Marcus S. C. Blagrove1 1Department of Evolution, Ecology, and Behavior, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, 2COVID-19 Outbreak Surveillance Team, UK Health Security Agency, 3Department of Livestock and One Health, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool Insects have an optimal environmental temperature range which they seek to remain within, and many external and internal factors can alter this preference. Here, we describe a cost-effective and simple method to study temperature choice, which allows insects to freely exhibit their natural behaviors.