Temperature-dependent life history and population parameters of Tetranychus evansi (Acari: Tetranychidae) on Solanum nigrum in Taiwan

Tetranychus evansi Baker & Pritchard is a destructive pest of solanaceous crops that causes severe damage, is aggressively invasive, and has recently invaded Taiwan. This study investigated the biology of T. evansi using Solanum nigrum L. as a host, focusing on the pest’s life history and population performance under varying temperatures to explore its ecological characteristics. The duration of the developmental stages of T. evansi decreased as the temperature increased, with only 6.18 days required to reach the adult stage at 30°C. The lower developmental threshold was 13.04°C, and the thermal constant was 108.23 degree-days. The lifespan of female mites also decreased with increasing temperature, being 11.11 days at 30°C. Male mites had the shortest lifespan of 20.85 days at 27°C. The total pre-oviposition period of females considerably decreased with increasing temperatures, with the longest oviposition period of 35.49 days occurring at 18°C, with an average of 195.74 eggs laid per female. Additionally, the net reproductive rate was highest at 18°C, reaching 133.72 eggs/female, and the intrinsic rate of increase (r) and finite rate of increase (λ) both increased with increasing temperature, reaching 0.4225 and 1.5258 day⁻¹ at 30°C, respectively. By contrast, the mean generation time decreased with increasing temperature, and was only 10.34 days at 30°C. This study provides crucial information regarding the ecology of T. evansi and can serve as a reference for future applied research.