Insect Folivory and Leaf Traits of Seven Hardwood Species in the Subtropical Rainforest of Fushan, Northeastern Taiwan

福山亞熱帶雨林闊葉樹昆蟲食葉程度與葉部特性

鹿兒陽(Erh-Yang Lu) ； 李治逸(Chih-Yi Lee)

《台灣林業科學》 25卷4期 (2010/12) Pp. 315-326

https://doi.org/10.7075/TJFS.201012.0315

摘要

為了解福山亞熱帶雨林的昆蟲植食行為，本研究選取7個福山常見闊葉樹種來進行調查，分別量取各樹種的昆蟲食葉程度（以葉面積損失率進行量化）及4個葉部特性（硬度、總酚類化合物、氮、磷）在季節上的變化，並分析葉面積損失率及葉部特性間的關係。
昆蟲造成的葉面積損失率在採樣月分間具顯著差異，以4月剛發出新葉的損失率最低，也就是昆蟲取食集中在新葉期間，葉片成熟後昆蟲取食壓力大幅降低。葉面積損失率在樹種間亦具顯著差異，年輕葉累積的葉面積損失率（到7月）以三斗石櫟(13.00%)最高，綠樟最低(2.96%)，其餘5個樹種在4.25~7.02%之間。
4個葉部特性在月份間均具顯著差異，以4月的年輕葉之硬度及總酚類濃度最低，氮、磷濃度則最高。葉部硬度、總酚類化合物濃度、氮濃度在樹種間也具顯著差異，但是年輕葉及成熟葉在樹種間高低順序不一致。年輕葉的葉面積損失比率與年輕葉的氮、磷濃度具顯著正相關，三斗石櫟年輕葉中氮、磷濃度最高，被昆蟲取食的比率也是最高的。
這些結果顯示福山亞熱帶雨林的樹種即使是處在相同的環境中，來自昆蟲的取食壓力卻不一致，取食壓力的差異可能與其葉部特性有關。葉面積損失主要發生在葉部完全成熟前，這應與植食昆蟲偏好幼葉的柔軟、低總酚類化合物濃度、高氮及磷濃度有關。

關鍵字

植食行為 ； 葉部特性 ； 氮 ； 磷 ； 總酚類化合物

並列摘要

To understand insect herbivory in the subtropical rainforest of Fushan, northeastern Taiwan, we investigated seasonal patterns of insect folivory (quantified by leaf area loss) and leaf traits (toughness, total phenols, N, and P) of 7 common hardwood species from March to November 2006. We also examined the relationships between the leaf area loss and the 4 leaf traits.
The leaf area loss (rate of insect folivory) significantly differed among sampled months and species. Folivory mostly occurred in leaves before maturation. The area loss in young leaves, which accumulated until July, was the highest in Pasania hancei var. ternaticupula f. ternaticupula (13.00%), while the lowest was in Meliosma squamulata (2.96%), and ranged 4.25~7.02% in the other 5 species.
All 4 leaf traits significantly differed among sampled months. Young leaves sampled in April were tender, low in total phenols, and high in N and P. The leaf toughness and concentrations of total phenols and N also differed among species. The area loss in young leaves was significantly positively correlated with the N and P concentrations in young leaves (sampled in April). The greatest leaf area loss occurred in P. hancei with the highest N and P concentrations in its young leaves.
The results suggest that even in the same habitat, hardwood species face different pressures of insect folivory in the subtropical rainforest of Fushan. Higher folivory appeared to occur in species with higher foliar concentrations of N and P. It was also clear that insect folivores favored young, tender leaves rich in N and P and low in total phenols.

並列關鍵字

folivory ； leaf traits ； nitrogen ； phosphorus ； total phenols