Tarbiat Modares University Journal of Agricultural Science and Technology 1680-7073 Articles in Press 2026 07 19 Transgenerational effects of a mixture of abamectin and thiamethoxam on demographic traits of Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) 29005 EN Maedeh Nazari 1Department of Plant Protection, Agriculture faculty, University of Kurdistan, Sanandaj, Iran. 0000-0001-6677-7267 Amin Sadeghi Department of Plant Protection, Agriculture faculty, University of Kurdistan, Sanandaj, Iran. 0000-0001-6048-3532 Mostafa Maroufpoor Department of Plant Protection, Agriculture Faculty, University of Kurdistan, Sanandaj, Iran 0000-0001-6677-7267 Journal Article 2026 05 11 Phytoseiid mites are essential natural enemies in integrated pest management (IPM) programs, offering eco-friendly alternatives to chemical control strategies. <em>Amblyseius swirskii</em> (Athias-Henriot) is a commercially significant predatory mite extensively used against soft-bodied pests, including spider mites, thrips, and whiteflies. This study determined the sublethal effects of two concentrations (LC₅ and LC₈)of a mixture of abamectin and thiamethoxam on the demographic traits of <em>A. swirskii</em> progeny (F₁ generation) produced by parents (F0 generation) treated using the age-stage, two-sex life table theory at a constant environmental condition (25 ± 1°C, 75±5% RH, and a 16:8 [L:D] photoperiod). The experiments employed the age-stage, two-sex life table approach, with the two-spotted spider mite (<em>Tetranychus urticae </em>Koch) serving as prey. Female life span was significantly shorter at LC₈ (9.49 days) than at LC₅ (10.29 days), whereas male life span did not differ significantly between LC₅ (9.38 days) and LC₈ (9.27 days). Net reproductive rate (<em>R</em>₀), intrinsic rate of increase (<em>r</em>), and finite rate of increase (<em>λ</em>) were significantly lower in both pesticide treatments than in the untreated control, whereas no significant differences were detected between LC₅ and LC₈. In contrast, the mean generation time (<em>T</em>) differed significantly among all treatments. These findings suggest that even low concentrations of this product can compromise key life history traits of <em>A. swirskii</em>, potentially limiting its efficacy in biological control programs. Therefore, evaluating the compatibility of acaricides with natural enemies is critical prior to their inclusion in IPM strategies. https://jast.modares.ac.ir/article_29005_3484e1bac36fc0d1f0e86ae3b5aed870.pdf