The Relationship of Biting Midges (Forcipomyia taiwana) (Diptera: Ceratopogonidae) Density with Algae on Habitat Tao-Mi Village, Puli Township in Nantou County

[[abstract]]本研究調查小黑蚊棲地的藻類相是否與其小黑蚊成蟲密度有相關，以作為小 黑蚊防治的參考。選定南投縣埔里桃米社區的10個採樣點，以誘集法調查小黑蚊成 蟲密度；並在採樣點附近採回定量藻類進行環境藻類種類與數量分析。結果發現樣 區各採樣點小黑蚊成蟲密度等級介於第3級至第5級，其中採樣點稻湘村民宿及採樣 點水溝2個地點為第5級，成蟲平均個數分別占18.03 %與16.70 %。藻類種類調查結 果顯示，共發現15屬16種藻類，其中藍綠藻有11屬12種，分別為Aphanothece sp.、 Borzia sp.、Cylindrospermopsis sp.、Gloeothece sp.、Lyngbya sp1.、Lyngbya sp2.、 Merismopedia sp.、Myxosarcina sp.、Nostoc sp.、Oscillatoria sp.、Phormidium sp.、 Raphidiopsis sp.；綠藻3屬3種，分別為Geminella sp.、Gonium sp.、Cosmarium sp.； 矽藻1屬1種Nitszchia sp.。以採樣點遊客中心的藻類種類數最多12種，採樣點親水公園 最低3種；另外，親水公園的藻類數量比例最高34.77 %，桃米泉農莊最低2.41 %。3種 主要藻類類群進行群聚分析顯示，10個採樣點可分為4群 (p<0.05)，樣點稻湘村民宿、 水溝及親水公園具較特有的藻類相而各自成群，其他7個採樣地點成1群。將16種藻類 分別與小黑蚊密度進行相關分析時，發現小黑蚊密度與特定的藻類呈現特定的關係，與 矽藻Nitszchia sp.呈現明顯的正相關(r= 0.71)，與2種藍綠藻Nostoc sp.和Raphidiopsis sp.有正相關的趨勢(r>0.5)，另與2種藍綠藻Borzia sp.和Merismopedia sp.呈現負相關的 關係(r<-0.45)。小黑蚊分布地點中的藻類相對豐度進行主成分分析，顯示兩個主要因子 可解釋樣本56.35 %以上的總變方。[[abstract]]This study herein, investigated whether the amount of algae in the biting midge habitats were related to the density of midge. Ten sampling sites were selected from Tao-Mi Village in Puli of Nantou Couny. Adult biting midges halted on investigator’s shanks were catched within 20 minutes using motor sucking collector. Meanwhile, algae from 4 cm2 area around the sampling site was collected, and examined and identifi ed using optical microscope. Results of biting midge showed that midge number in these sampling sites were between degree 3rd -5th; and sampling sites, 1 and 2 with proportion of 18.03% and 16.70%, respectively, out of total number belonging to degree 5th. When compared the biting midge density on each sampling sites with its relative distances, and showed no signifi cant relationships between them. There are 15 genera involving 16 species algae were found in these sampling sites, in which 11 genera with 12 species are blue-green algae, three genera with 3 species are green algae, and one genus with one species is diatom. Twelve algal species in sampling site 9 is the highest, and three species in sampling site 5 is the lowest. Moreover, the proportion of individuals, 34.77%, in sampling site 5 is the highest and 2.41% in sampling site 5 is the lowest. With respect to algae quantity, the blue-green algae has the highest amount of 83.25% and the green algae has the lowest of 0.73%. Result of multidimensional scale analysis of algae showed that 10 sampling sites can be separated into 4 groups (p<0.05), in which the sampling sites 1, 2, and 5 each formed a separate group because of its peculiar algal composition and the remaining 7 sampling sites formed one group. For correlation analysis between 16 algae species and the biting midge density, the results showed that the biting midge density revealed some specific relationships with certain algae. It is having significant positive relationships with Nitszchia sp. of diatom (r=0.71), with Nostoc sp. and Raphidiopsis sp. of bluegreen algae (r>0.5), and negative relationships with the other two blue-green algae of Borzia sp.and Merismopedia sp. (r0.45) were chosen to be compared with the biting midge density for further correlation analysis, the algae exhibited signifi cant relationship with midge density (r>0.7). When principal component analysis base on relative abundance of algae was performed, two principal factors representative 56.35% of total variance can be extracted. The major descriptive algae in factor 1 (or PCA1) are Cylindrospermopsis sp. and Aphanothece sp., which distributed mainly in the sampling site 1, and showed signifi cant correlation (r>0.88). However, the descriptive algae in factor 2 are Gloeothece sp., Gonium sp., and Nostoc sp., which distributed mainly in the sampling site 2, and also showed signifi cant correlation (r>0.91) in their pairwised comparisions