Functional and numerical response comparison of Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) to Frankliniella occidentalis (Pergande) and Tetranychus urticae Koch

Abstract Background The predatory mite Neoseiulus californicus (McGregor) is extensively used in biological control programs, yet quantitative comparisons of its efficacy against different pest species remain limited. This study systematically quantified and compared the functional and numerical responses of N. californicus to two economically significant pests: the two-spotted spider mite, Tetranychus urticae Koch and western flower thrips, Frankliniella occidentalis (Pergande), across egg and first-instar larvae under controlled laboratory conditions. Results N. californicus exhibited a Type II functional response to all prey stages (R² = 0.955–0.994). Attack rates were 1.2–1.7 times higher for T. urticae (0.72–0.76 day⁻¹) than F. occidentalis (0.45–0.59 day⁻¹). The most pronounced difference was handling time: 7.6–9.3× times shorter for spider mites (3.7–3.9 min.) than thrips (29.5–34.7 min.), resulting in maximum predation rates of 370–385 vs. 41–49 prey day⁻¹. At operational densities (15–30 prey/arena), predation efficiency was 72.4% for spider mites vs. 53.5% for thrips. Oviposition rates were 1.39× times higher on T. urticae (2.50 ± 0.27 eggs female⁻¹ day⁻¹) than F. occidentalis (1.80 ± 0.22 eggs/ female/ day). An integrated performance index was 2.89× times higher for spider mites, with optimal predator deployment densities at 18.7 and 22.3 prey per arena for T. urticae and F. occidentalis , respectively. Conclusion N. californicus demonstrates greater predatory and reproductive performance against T. urticae compared to F. occidentalis , driven by more efficient prey handling and enhanced reproductive output under laboratory conditions. These results suggest predator: prey ratios of 1:6–1:10 as a theoretical baseline for spider mite management. These ratios represent a theoretical starting point for hypothesis generation; field validation is required before operational application. For thrips control, N. californicus should be integrated with complementary approaches. These laboratory-derived parameters provide a quantitative foundation for designing future field studies and informing the development of release strategies.