臺灣水青岡林的鱗翅目種豐富度

Abstract

植食性昆蟲通常對寄主植物有高度的偏好，亦包含以植食性昆蟲為主要成員的鱗翅目。鱗翅目之寄主範圍及在不同寄主上的多樣性及差異也常受到關注。根據世界鱗翅目昆蟲資料庫記載，水青岡屬植物蘊含豐富鱗翅目資源，全世界以其為寄主之種類繁多。先前研究估計臺灣約有83種昆蟲以臺灣水青岡為寄主，但大多數種類生態習性尚未明瞭。臺灣水青岡為冰河孑遺物種，為受紅皮書保護的易危物種，僅片斷分佈於臺灣北部氣候適宜的山頭上。本研究調查臺灣水青岡林的鱗翅目昆蟲資源，比較各樣區之物種組成，並探討水青岡林棲地面積及物種多樣性的關係。以臺灣僅存的五個水青岡林作為研究樣點，以集群分析檢測各地區鱗翅目組成差異，並以物種－面積關係探討鱗翅目與水青岡林面積大小之關係，然後使用發生率模型來模擬各地區鱗翅目的交流。至今共記錄21科118種以臺灣水青岡為寄主的鱗翅目昆蟲，以銅山地區最多，並包含25種專食水青岡的物種。組成部分以插天山與鳥嘴山地區最為接近，大白山則差異最大。物種－面積關係模型顯示水青岡林面積與物種數成正比，z值為0.377。各樣區所計算之發生率模型則都趨近於零。以物種數而論，臺灣水青岡林具高鱗翅目多樣性，符合避難所的特性。包含廣食性昆蟲的組成模式可能受海拔及伴生樹種影響，專食則可能受水青岡林面積影響。模型顯示物種隨臺灣水青林面積上升，且在不同地區間呈現高度隔離狀態。Phytophagous insects usually have a high preference for host plants, and also include lepidoptera, which are mainly herbivorous insects. The host range of lepidoptera and the richness in different trees has received considerable attention. According to the records of the “HOSTS - a Database of the World's Lepidopteran Hostplants”, there is a high lepidopteran diversity in genus Fagus. There are an estimated 83 species of insect with Taiwan beech (Fagus hayatae) as their host plant, but the identification and habits of most species are unknown. Fagus hayatae is a glacial relict plant and a vulnerable species protected by the IUCN Red List. Only distributed on the hilltops in northern Taiwan with a favorable climate. This study investigates the lepidopteran resources and composition of the Taiwan beech forest, and explores the relationship between the habitat area and species richness. Taking the only five remaining beech forests in Taiwan as sample points, cluster analysis was used to detect the differences in the composition of Lepidoptera in each region, and the relationship between the richness of lepidoptera and beech forest area was explored by species-area relationship model, and use the Incidence Function Model to simulate species flows of every site.There are 118 species of lepidopteran insects in 21 families have been recorded, with the largest number in the Tongshan area, and 25 species that specialize in Fagus. The components are the closest to the Chatian Mountain and the Niaozui Mountain, while the Dabai Mountain has the largest difference. The species-area relationship model shows that the area of the forest area is proportional to the number of species, and the z value is 0.377. The Incidence Function Model shows that in all plot are close to zero. The beech forests of Taiwan have high lepidopteran diversity, which is in line with the characteristics of refugia. The composition pattern that contains polyphagous lepidoptera may be affected by altitude and associated tree species, while the monophagy species may be affected by the area of the forest. The model shows that species increase with the area of Taiwan beech forests, and they are highly isolated among different area.