鹽類對埃及斑蚊、熱帶家蚊及臺灣鋏蠓卵殼構造之影響

Effects of Salts on the Eggshell Structure of Aedes aegypti, Culex quinquefasciatus and Forcipomyia taiwana

翁淩維(Ling-Wei Weng)

指導教授 ： 黃榮南

國立臺灣大學/生物資源暨農學院/昆蟲學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201900288

摘要

埃及斑蚊 (Aedes aegypti (Linnaeus))、熱帶家蚊 (Culex quinquefasciatus Say) 與臺灣鋏蠓 (Forcipomyia taiwana (Shiraki)) 皆為臺灣重要騷擾害蟲，除了吸血行為造成人體過敏或紅腫的情形，埃及斑蚊及熱帶家蚊還可傳播蚊媒疾病，造成人類健康危害，以往主要於幼蟲或成蟲期間進行防治，在卵期的探討甚少。前人研究指出雌蟲卵產於含氯化鈉基質時，無法順利黑化，而產於含硫酸鎂基質時，熱帶家蚊的蚊卵無法順利黑化，但埃及斑蚊及臺灣鋏蠓卵皆能夠黑化。本研究進一步探討氯化鈉及硫酸鎂水溶液處理後蟲卵外觀、卵殼表面顯微差異及發育過程中包覆胚胎，使卵具有抗乾燥能力 (egg resistance to desiccation) 的漿膜表皮 (serosal cuticle) 研究。也探討埃及斑蚊卵卵殼剖面構造、造成卵殼黑化的原酚氧化酶V (prophenoloxidase, proPO) 基因表現模式，及與漿膜表皮形成相關的幾丁質合成酶基因表現模式。結果顯示，鹽類水溶液處理後的蟲卵，無法黑化的組別，長度均有顯著的縮短，卵殼表面的突起比例也有增加情況或外卵黃膜區 (outer chorionic cell) 面積下降，顯示鹽類水溶液會造成無法黑化蟲卵卵殼皺縮。以幾丁質染劑確認漿膜表皮僅存在於自然產的黑化卵中。此外，埃及斑蚊的幾丁質合成酶表現與漿膜表皮的形成時間吻合。氯化鈉水溶液處理的埃及斑蚊卵殼可維持外卵黃膜 (exochorion) 及內卵黃膜 (endochorion) 的構造，而內卵黃膜有顯著的增厚 (0.4~0.5 μm)。以反轉錄聚合酶連鎖反應偵測卵的原酚氧化酶V基因表現，在蒸餾水、氯化鈉及硫酸鎂水溶液處理皆有表現，定量即時聚合酶連鎖反應結果顯示，硫酸鎂水溶液處理之自然產黑化蚊卵及氯化鈉水溶液處理之解剖未黑化蚊卵，兩者表現量有顯著下降，表示影響卵殼黑化的原因仍有待研究。

關鍵字

埃及斑蚊 ； 熱帶家蚊 ； 臺灣鋏蠓 ； 卵殼 ； 漿膜表皮 ； 原酚氧化?V ； 幾丁質合成?

並列摘要

Aedes aegypti (Linnaeus), Culex quinquefasciatus Say and Forcipomyia taiwana (Shiraki) are important nuisance pests in Taiwan. All of them would make people allergic reaction through the bloodsucking and Ae. aegypti and Cx. quinquefasciatus also can spread diseases and harm human healthy. The control strategies always focus on larval and adult stage instead of the egg stage. Previous study suggested that eggs laid on the NaCl-containing medium are unable to melanize. When laid on MgSO4-containing medium, the eggs of Ae. aegypti and F. taiwana but not Cx. quinquefasciatus, are able to melanize. This study further investigates the effect of NaCl and MgSO4 solutions on the surface of eggs, structure of eggshell and serosal cuticle which contribute the eggs resistance to desiccation on Ae. aegypti, Cx. quinquefasciatus and F. taiwana. Our results showed that the unmelanization group of salt-treated eggs become shorter in length, outer chorionic cell decreased in area or tubercle increased in area ratio. These results indicate the egg become shrunk due to the failure of melanization. Moreover, the serosal cuticle only existed in the naturally laid and melanized eggs. Transection of NaCl-treated Ae. aegypti eggs showed that the eggshell had two intact layers (exochorion and endochorion) and the width of endochorion showed significantly wider (0.4-0.5 μm). The major prophenoloxidase gene (proPO5) responsible for egg melanization was expressed in all treatments, however, the expression level was significantly decreased in MgSO4-treated naturally laid eggs and NaCl-treated dissected eggs. The reason of salts influence egg chorion melanization is still unknown and deserves further investigation.

並列關鍵字

Aedes aegypti ； Culex quinquefasciatus ； Forcipomyia taiwana ； eggshell ； serosal cuticle ； prophenoloxidase ； chitin synthase

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