密滅汀致死與跨代效應對二點葉蟎生活史之影響

The Lethal and Transgenerational Effects of Milbemectin on the Life History and Population Parameters of Tetranychus urticae

二點葉蟎（Tetranychus urticae Koch）是危害許多農作物的重要害蟎，在田間主要以化學農藥進行管理。密滅汀是防治二點葉蟎的殺蟎劑之一，然而，密滅汀對二點葉蟎噴施後的當代存活個體的壽命與繁殖，以及存活個體後代的族群表現尚未明瞭。在本研究中，我們在室內探討密滅汀半致死濃度處理後對二點葉蟎當代存活雌蟎之壽命與繁殖表現，並分析此存活個體繁殖後代之族群表現。試驗結果顯示，經密滅汀半致死濃度處理的當代二點葉蟎比對照組表現出較強的適應性，雌蟎的壽命和產卵期相對較長；在其後代的發育時間雖然較長，但卻表現出較高的繁殖力和淨繁殖率（R0）。因此，密滅汀的半玫死濃度似乎能有效促進二點葉蟎族群的增長。我們的研究揭示了密滅汀對二點葉蟎的致死性和跨代的影響，提供使用密滅汀在管理二點葉蟎上之重要參考資訊。在密滅汀的運用上應更加的謹慎，方能達到更佳運用在管理二葉葉蟎上的策略。

The two-spotted spider mite, Tetranychus urticae Koch, is a major agricultural pest that infests a wide range of crops and is primarily managed with acaricides. However, the transgenerational effects of milbemectin, a commonly used broad-spectrum miticide, on T. urticae remain poorly understood. This study evaluated the acute lethal effects of milbemectin on adult female mites and its transgenerational impacts on their offspring under laboratory conditions. Using probit analysis and the age-stage, two-sex life table, we found that exposure to the median lethal concentration (LC50) of milbemectin enhanced T. urticae fitness. Specifically, treated females exhibited longer lifespans and extended oviposition periods compared to controls. In the subsequent generation, offspring from treated females had longer developmental periods but achieved higher fecundity and net reproductive rates (R0). These findings indicate that the LC50 of milbemectin can promote population growth in T. urticae. Our results highlight the importance of understanding both the lethal and transgenerational effects of milbemectin for effective pest management. Caution is advised when using milbemectin to develop more sustainable strategies for controlling T. urticae.