- 期刊
- OpenAccess
Genetic Differentiation of the Eulophid wasp Quadrastichus erythrinae Kim (Hymenoptera: Eulophidae) from Various Erythrina Hosts Based on Mitochondrial and Nuclear Genes
由粒線體與核基因探討各類寄主植物之刺桐釉小蜂的遺傳變異
摘要
刺桐釉小蜂於2000年首先被報導嚴重感染非洲東部模里西斯、留尼旺島以及亞洲新加坡的刺桐樹，並造成部份植株死亡，旋即迅速蔓延到全球熱帶與亞熱帶島嶼或陸塊邊緣地區。由於受害的寄主植物種類及病徵程度不同，這些感染的昆蟲是否為同一種，令人產生質疑。我們選擇台灣本島與其離島等14個地區的36個樣本，及該物種最早報導之發生地模里西斯與新加坡的11個樣本；應用粒線體的12S核醣體RNA(12sRNA)，細胞色素氧化酵素第一單元(COI)以及核DNA的核醣體第二區間(ITS2)等區域之DNA片段，分析來自不同地區，不同寄主植物上的刺桐釉小蜂之遺傳變異與親緣關係。結果顯示所有不同地點與不同寄主植物上的昆蟲樣本在同片段的序列皆無差異，顯然全台各地及取樣之其他國家的刺桐屬植物上的害蟲均為同種之刺桐釉小蜂，這些受害嚴重地區的刺桐釉小蜂顯然來自同一個基因型快速擴散的結果。
並列摘要
Since 2000, many Erythrina trees have been found initially wilting and later suffering die-back due to severe infestations by Quadrastichus erythrinae Kim (Hymenoptera: Eulophidae) in Mauritius, Réunion, and in Singapore. These infestations have since spread into several tropical and subtropical countries. Various degrees of damage and different symptoms have been observed in different host species which has raised the question whether the pests all belong to the same species or not. In order to measure the differentiation in the eulophid wasps from different geographical areas and various Erythrina host plants, 36 samples on 6 host taxa from 14 localities in Taiwan and 11 samples on 2 host species from Singapore and Mauritius were collected. Singapore and Mauritius were two of the three countries included in the original description of Q. erythrinae. We analyzed the mitochondrial genes of 12S ribosomal RNA and cytochrome oxidase I, and the nuclear sequence of intergenic spacer 2 to understand their genetic variation and phylogenetic relationship. Sequences of the same region in all the three genes were identical among all the samples. The homogeneity of the genetic composition suggests that there were no cryptic species in the samples. This confirms that all the wasps sampled in this study, despite their different origin of both area and host, belong to the same species. It is evident that all these pests from these countries came from the same monomorphic genotype which quickly and widely spread to other areas.