Effects of small-scale temperature shifts on

Variations in environmental parameters such as temperature and relative humidity (RH) can significantly affect mass-rearing outcomes and quality assessment. While the impact of broad temperature changes is well documented, the effects of small-scale fluctuations (1–2 °C shifts) on development and quality remain largely unexplored. This study was carried out to investigate the responses of Aedes aegypti and Aedes albopictus to incremental changes in rearing temperature and to evaluate the influence of temperature and RH on quality assessment with the Food and Agriculture Organization of the United Nations/International Atomic Energy Agency (FAO/IAEA) flight test device (FTD). First-instar larvae were reared under controlled conditions at five constant temperatures (26, 27, 28, 29 and 30 °C) maintaining the larval density and feeding regime as applied in mass-rearing conditions. Key parameters assessed included time to pupation, pupation rate, male escape rate, and body size. Additionally, male Ae. aegypti escape rate was evaluated under varying room temperatures and RH levels to assess the consistency and reliability of the FTD. Small-scale temperature fluctuations significantly impacted key life-history traits of Aedes mosquitoes, with higher temperatures accelerating time to pupation and enhancing pupation rates in both Ae. aegypti and Ae. albopictus. Moreover, Aedes albopictus consistently exhibited lower pupal yields and male escape rates compared to Ae. aegypti. Adult male quality assessed using the FTD was significantly influenced by the environmental temperature, but showed no significant variation in response to changes in RH. These results highlight the importance of precisely controlling environmental conditions during larval mass-rearing and adult quality assessment using the FAO/IAEA FTD to ensure consistent and reliable outcomes.