非洲菊斑潛蠅的寄主偏好性及其在不同寄主上之特徵變異(雙翅目：潛蠅科)

Abstract

非洲菊斑潛蠅 (Liriomyza trifolii) 是一種高度多食性且為世界性分布的重要農業害蟲，根據統計，其寄主植物囊括了 25 科，共超過 400 種以上的記錄，是潛蠅科中非常少數特殊的多食性種類。雌蟲將卵產在寄主植物的葉肉中，幼蟲孵化後便在葉片中進行潛食，直到化蛹前都不會離開，於是雌蟲在產卵時便決定了卵及幼蟲在寄主植物上的命運，顯示出雌蟲的寄主選擇對延續族群的重要性。本研究以菜豆做為維持非洲菊斑潛蠅母族群的寄主植物，在24.5 ± 1˚C, 70 ± 10% R.H., 12L : 12D的環境下，讓非洲菊斑潛蠅對大花咸豐草 (Bidens alba)、菜豆 (Phaseolus vulgaris)、油菜 (Brassica campestris)、番茄 (Lycopersicon escultentum) 這四種寄主植物進行產卵及取食偏好性測試，發現雌蟲對大花咸豐草存有顯著的取食及產卵偏好，而在菜豆上取食的幼蟲具有最高的蛹重、存活率及羽化率。另外自母族群分出一個族群改以油菜進行累代飼養，經過 13 個世代後再比較其與母族群在寄主偏好性、形態及遺傳特徵上的表現：在偏好性方面，供予兩族群菜豆及油菜葉片做寄主選擇，發現菜豆族群對兩種寄主的偏好情形達顯著差異水準，但油菜族群對兩者的利用情形則已無顯著差異；在形態特徵方面，對兩族群不同世代的雄性個體作取樣並對其翅上的 17 個翅脈接點進行幾何形態測量學之疊合法與薄板曲線法的分析，發現在內橫脈及外橫脈上的四個接點具有方向性的變異，且隨著世代數的增加，兩族群的樣本分布範圍似乎存有不同的發展方向；在遺傳特徵上，以粒線體 DNA COI 及 COII 片段進行序列分析，根據試驗所得的分子資料，目前並沒有發現可供區辨此兩族群之分子標示區段，在親緣關係樹上也沒有明顯的分群區隔，另外經由總蛋白條帶數、蛋白條帶的分子量及移動率的分析結果顯示兩族群的雄性個體在全蛋白質 SDS-PAGE 的結果上亦無差異存在。

Liriomyza trifolii is a highly polyphagous and cosmopolitan pest. According to the investigation, the host range of L. trifolii has extensive embraced more than 400 species in 25 families. Females of L. trifolii lay eggs in the leaves; after hatching, larvae feed in the leaves and will not leave until pupation. Actually, females lay eggs in which host will determine the fate of the larvae; and that indicates the importance of the host preference of females. In this study, I used kidney bean (Phaseolus vulgaris) to rear L. trifolii stock at 24.5 ± 1˚C, 70 ± 10% R.H., photoperiod 12L : 12D and offered beggar-tick (Bidens alba), kidney bean, rape (Brassica campestris), and tomato (Lycopersicon escultentum) as foods for females to test their host preference. The results showed that females exhibited significantly feeding and ovipositional preference on beggar-tick, and larvae ate in kidney bean have highest pupal weight, survivorship and emergence rates. On the other hand, another colony reared on rape was also established. After 13 generations, the host preferences of the two colonies were compared. The data showed that kidney bean colony has significantly feeding and ovipositional preference for kidney bean, but rape colony has no significant difference for the preference between the two plants. Moreover, I also analysed the traits variation for these two populations. For morphometric studies, 17 landmarks data from connective points of wing veins were selected and used for superimposition and Thin-plate spline-based analysis to detect the morphological variations among populations. The results showed there have directional variations on the endpoints of inner and outer cross veins in each generation. As time goes by, it seems that there are two different, potential directions of the sample variations of the two colonies. Phylogenetic relationships among populations were also reconstructed by using DNA sequencing data of about 1,018 bp of mitochondrial cytochrome oxidase subunit I and II genes. Unfortunately, I did not find any useful molecular markers that can successfully divide those two colonies from different host plants. Meanwhile, the data of total protein analysis can not show the differences between colonies neither.