臺灣銀合歡長角象鼻蟲（鞘翅目：長角象鼻蟲科）的寄主植物紀錄與鑑定

Host plant records and identification of Araecerus levipennis in Taiwan

臺灣銀合歡之種子獵食者（seed predators）銀合歡長角象鼻蟲（Araecerus levipennis Jordan）分布於東南亞多個地區，在臺灣以銀合歡（Leucaena leucocephala（Lam.）de Wit）為主要寄主，亦可在毛苦參（Sophora tomentosa L.）、金合歡（Acacia farnesiana（L.）Willd.）等植物繁衍。本研究於屏東地區進行野外觀察與採集製作標本，探討銀合歡長角象鼻蟲於宿主銀合歡上之互動行為與動態，發現銀合歡長角象鼻蟲之產卵量非常高，幼蟲對銀合歡種子能夠造成不規則狀破壞，惟其幼蟲在銀合歡上有較高的死亡率，據觀察顯示銀合歡長角象鼻蟲於銀合歡上完整生活史約一個月，不過仍顯示銀合歡長角象鼻蟲具有相當的生物防治潛力。銀合歡長角象鼻蟲外觀普遍為褐色且具有細毛，藉由不同深淺顏色細毛排列形成多種紋路，體長3.00±0.26 mm，體寬1.42±0.12 mm，其生理、行為等與棉實長角象鼻蟲（Araecerus fasciculatus（DeGeer））相似。形態上兩種象鼻蟲的差異在足之脛節，棉實長角象鼻蟲具黑色斑點故顏色呈現深淺交錯，而銀合歡長角象鼻蟲則單純褐色；解剖銀合歡長角象鼻蟲陽莖，末端呈現叉狀且內囊骨特化為翼狀。本研究同時將兩種長角象鼻蟲COI序列與NCBI資料庫中序列進行比對，發現兩者的差異為18%。銀合歡長角象鼻蟲在臺灣具有做為防治資材的潛力，應持續評估此種子獵食者帶來的效益與風險。

"An Araecerus beetles, Araecerus levipennis Jordan attacking the seeds of Leucaena leucocephala (Lam.) de Wit was found and it can also reproduce on Acacia farnesiana (L.) Willd. and Sophora tomentosa L. We carried out field observations and collected specimens in Pingtung. The distribution, bionomics and mortality of Ar. levipennis are discussed. The larva presented a high mortality rate feeding on L. leucocephalus. The complete life history of the Ar. levipennis is about one month. Its body length and width is 3.00 ± 0.26 mm and 1.42 ± 0.12 mm, respectively. Ar. levipennis are similar with Ar. Fasciculatus (DeGeer), an important storage pest in Taiwan. The only difference of morphology is on the color of tibia and male reproductive organ. We also sequenced COI gene of both species and revealed that the divergence rate is 17.67%. Ar. levipennis has the potential to be released as a biological control agent in Taiwan, but its host range partially overlaps with Ar. fasciculatus, the risks and assessments of the seed predator should be carefully evaluated."