白毫烏龍(俗稱東方美人茶)為台灣茶品中最具特殊風味者，茶芽經茶小綠葉蟬 (Jacobiasca formosana (Paoli))取食刺激後產生特殊蜜香，但其中的機制尚未完全明瞭。本研究利用粒線體COI序列以及外部形態特徵探討台灣各地茶園茶小綠葉蟬的分類，並藉由觀察茶葉受茶小綠葉蟬取食刺激後的組織及化學改變，釐清其間的互動與影響。採自烏來、坪林、楊梅、峨嵋、名間以及鹿野各地茶園之茶小綠葉蟬雄蟲外部形態無明顯差異，雌蟲的產卵管則在瓣片末端的鋸齒結構數出現差異，各地區樣本之體染色體ITS2基因分群不明顯且差異小，而粒線體COI基因雖分群亦不明顯，然樣區個體遺傳變異最高達3.3%。利用粒線體COI基因所建構之分子時鐘顯示台東地區的茶小綠葉蟬在一百萬年前即出現，而其他地區族群則在六十萬年前分化成兩支。綜合形態特徵與分子分析結果顯示多數地區之茶小綠葉蟬為同種，而台東地區茶小綠葉蟬可能因冰河期影響而產生分化，但可能因人為因素而有基因交流。茶葉經茶小綠葉蟬取食刺激後，外觀產生先紅點而後紅脈，組織切片顯示葉脈組織會受到茶小綠葉蟬取食的影響而隨時間變化，褐化現象在8小時內由韌皮部周圍到木質部，相對地，物理性破壞所造成的褐化則侷限在針刺路徑，不會擴散。在高效液相層析(high-performance liquid chromatography, HPLC)及氣相層析(gas chromatography – mass spectrometry, GC-MS)分析發現高著涎(取食)茶菁之兒茶素類含量較高，且經烘焙製為成茶後，兒茶素類降解並進而累積沒食子酸而同時帶有香甜氣味之揮發性成分含量亦增加，而此成分可能與茶葉特殊的蜜香味相關。本研究結果可作為未來瞭解白毫烏龍蜜香生成機制之基礎。 White tip oolong tea, also referred to as Oriental Beauty or Puff Tea, is an exceptional tea in Taiwan. Its special honey aroma is induced by the infestation of tea green leaf hopper, Jacobiasca formosana (Poli), which belongs to the subfamily Typhlocybinae, tribe Empoasini. To better understand the interactions between the insect and the tea plant, studies were undertaken that included the taxonomy of green leaf hoppers, an examination of plant tissue variation after feeding by insects, and chemical change after infestation. Tea green leafhoppers from major tea gardens in Taiwan were sampled for taxonomic study of both molecular and morphological characters. Although the ITS2 gene shows low variations, the mitochondria COI gene shows high variations (up to 3.3%) among populations in different sites. The COI molecular clock indicates that a part of population in Luye diverged one million years ago and two major divergence among other populations occurred in 60 million years ago. The morphology of the female ovipositor shows differences between samples from Luye, Taitung, when compared to populations from other tea gardens. The morphological and molecular results suggests that the population from Luye might be a cryptic species while all other population appear to be a wide spread species. Free-hand sectioning revealed that the vascular tissue of tea leaf changes progressively color around phloem to xylene after feeding by tea green leafhoppers while the browning effect of physical damage confined in the area around the stabbing of minute pin. Samples were analyzed for fresh leaves and baked leaves with low, moderate and high degrees of infestations. Analyses of chemical composition through high-performance liquid chromatography (HPLC) showed that there are significantly more epigallocatechin gallate (EGCG) in highly infested fresh-leaf samples than in those with moderate and low infestation levels. This phenomenon does not hold for baked leaves. Analyses via gas chromatography – mass spectrometry (GC-MS) revealed a higher content of volatiles in the highly infested samples which is congruent with the distinctive flavor of white tip oolong tea. This study provides a basic knowledge of the interactions between tea green leafhoppers and tea, and as well, a foundation for future research on the mechanisms of these taxa.