Mark-release-recapture study of irradiated male Aedes albopictus under stressful field conditions

The sterile insect technique (SIT) suppresses mosquito populations by releasing sterile males. Its success mainly depends on the performance of sterile males. Mark-Release-Recapture (MRR) experiments are used to evaluate male performance in the field, yet most previous experiments were conducted under mild conditions (e.g. 25-28 °C) in which mosquitoes could easily adapt. Male mosquito performance under stressful field conditions remains poorly understood. This study evaluated the field performance of irradiated Aedes albopictus males under high-temperature conditions (>30 °C in average) in southern China, Foshan City, located in a sub-tropical area. Two MRR experiments were conducted in a 5-ha village during July-August of 2023 and 2024. Lifespan and dispersal of postreleased males were examined using BG-Sentinel mosquito traps, human landing catches, and ovitraps.

A total of 54 546 and 58 440 sterile males were released in 2023 and 2024, respectively, with recapture rates of 8.53% and 5.64%. The mean dispersal distances ranged from 58.88-77.19 m (2023) to 81.82-90.86 m (2024). Daily survival probabilities were 0.15-0.28 in 2023 and 0.45-0.62 in 2024, corresponding to average expected lifespans of 0.53-0.78 days and 1.26-2.13 days, respectively. Estimated wild male densities ranged from 302-986 males ha^-1 in 2023 to 416-3785 males ha^-1 in 2024.

Stressful field conditions severely reduced sterile male survival and dispersal, highlighting the need to optimize release protocols in challenging climates. These findings provide critical baseline data for advancing Ae. albopictus SIT programmes in southern China. © 2026 Society of Chemical Industry.