物理及化學因子對臺灣鋏蠓生長之影響

Abstract

臺灣鋏蠓為目前臺灣地區重要騷擾性衛生害蟲，對戶外活動及人類健康造成負面影響。目前主要以人體誘集法監測族群，防治方式則多仰賴化學藥劑，惟長期施用恐造成環境汙染及健康風險，急需研發監測及防治之替代方法。本研究旨在尋找影響臺灣鋏蠓成蟲行為及未成熟期生長之物理及化學因子，以評估其做為防治資材之潛力。結果顯示 (1) 土臭素 (Geosmin) 為具誘引蚊蟲產卵效果的有機揮發性化合物，1 ppm濃度的土臭素也具誘引臺灣鋏蠓產卵作用，無論在含食物來源 (小球藻) 與否的基質上，其誘引產卵率為32~33 %；而甜菜根萃取液具更好的誘引產卵效果 (46~63 %)，可做為土臭素的潛在替代來源，惟田間測試誘卵效果仍待改善。此外，聚二甲基矽氧烷 (Polydimethylsiloxane; PDMS) 為具蚊蟲產卵忌避作用的有機矽化合物，但對臺灣鋏蠓無顯著的忌產卵效果； (2) 在不同亮度 (400、800、1600 lux) 條件下，偏振可見光雖對臺灣鋏蠓雄蟲和未吸血雌蟲無顯著偏好影響，但在800 lux的水平偏振可見光對懷卵雌蟲可能具忌避作用； (3) 臺灣鋏蠓未成熟期均生活於土表，分析大坑 (高密度區) 和科博館 (中低密度區) 地區幼蟲孳生地土壤性質，包括酸鹼度、電導度、水分含量、質地%和可交換性陽離子濃度 (Ca2+、Mg2+、K+、Na+)，使用多變量相關分析和複線性迴歸模型，評估與田間成蟲密度的相關性，顯示土壤中Na+濃度與田間成蟲密度呈負相關。(4) 仿間普遍認為苔蘚植物為臺灣鋏蠓發生根源，評估臺灣鋏蠓幼蟲於三種苔蘚植物 (真苔科、細鱗蘚科、羽苔科) 上的生長發育，顯示其化蛹率介於19.31~23.58 %，皆遠低於小球藻餵養組 (83.16 %)。雖提高藻類培養液中K2HPO4濃度4倍 (18.03 μM至72.10 μM)，可於24天增加2倍藻類數目，但CaCl2和K2HPO4濃度增加至0.5、1 M之後，會導致67~100 %和65~98.5 %的臺灣鋏蠓幼蟲死亡，然相同濃度之MgSO4對臺灣鋏蠓幼蟲生長則無影響。本研究初步建立多項具應用潛力之臺灣鋏蠓理化因子，有利於未來開發誘產卵與抑制幼蟲生長發育之綜合管理策略。

Biting midge, Forcipomyia taiwana (Diptera: Ceratopogonidae) is a nuisance anthropophilic pest in Taiwan, and its bite can cause severe itching and anaphylactic reactions, adversely affecting residents and the tourism industry. Currently, population monitoring relies primarily on human bait traps, while chemical control remains the dominant strategy during their outbreak, posing risks to both the environment and human health. Therefore, the development of both ethical and environmentally friendly alternatives for monitoring and control strategies is urgently needed. This study aimed to identify physical and chemical factors that influence the behavior of adult F. taiwana and the development of its immature stages, in order to evaluate their potential for use in control strategies. The results showed that (1) Geosmin, a volatile organic compound known as mosquito oviposition attractant, significantly attracted oviposition of F. taiwana at a concentration of 1 ppm, with oviposition rate ranging from 32–33 % regardless of the presence of a food source (Chlorella vulgaris). Beetroot extract exhibited a higher oviposition rate (46~63%) and may serve as a potential substitute for geosmin, however its field efficacy requires further improvement. Polydimethylsiloxane (PDMS) is a silicone-based compound that has been reported to act as mosquito oviposition deterrent, but it did not significantly interfere with the oviposition of F. taiwana. (2) Under different light intensities (400, 800, 1600 lux), polarized visible light had no significant effect on the behavior of males and blood-unfed females; however, horizontally polarized light at 800 lux may elicited an avoidance response in gravid females. (3) Field soil samples collected from Taichung Dakeng (high population density area) and the National Museum of Natural Science (low to medium population density area) were analyzed for pH, electrical conductivity, moisture content, texture, and concentration of exchangeable cations (Ca²⁺, Mg²⁺, K⁺, Na⁺). Results from multivariate correlation analysis and multiple linear regression models revealed that a negative correlation between soil Na⁺ concentration and F. taiwana abundance in the field. (4) The pupation rates of F. taiwana larvae reared on three moss species (Bryaceae, Thuidiaceae, and Lejeuneaceae) were ranged 19.31~23.58 %, which were significantly lower than that reared on Chlorella vulgaris (83.16%). Increasing K₂HPO₄ concentration in algae medium (18.03 μM to 72.10 μM) could double the growth rate of algal in 24 days, however higher concentration of CaCl₂ and K₂HPO₄ (0.5, 1 M) led to 67~100 % and 65~98.5 % larval mortality, respectively. MgSO4 has no effect on the growth of F. taiwana larvae. These studies identified potential physicochemical factors affecting the growth of F. taiwana, which will facilitate the development of integrated management strategy against this blood-sucking midge.