| Summary: | 碩士 === 國立臺灣大學 === 昆蟲學研究所 === 89 === Fruit flies and weevils (rice and maize weevils) are both major agricultural pests, and their distribution will grow as global trade activity increases. Identification based on the larvae and developing embryo characteristics of fruit flies is difficult, and weevils are morphologically similar. The application of molecular biotechnology promises a more effective method of identification. In this study, we attempted to develop DNA molecular markers for identifying the oriental fruit fly (Bactrocera. dorsalis (Hendel)) and two morphologically similar weevils (Sitophilus oryzae (L.) and S. zeamais Motschulsky). Our strategy was, first, to extract the genomic DNAs from insects and then to identify the species by a rDNA-PCR method. Finally we discuss the phylogenetic relationships among the geographical isolates in Taiwan.
The genomic DNAs extracted from the appendage and developing larvae of the oriental fruit fly were used to determine the end concentration for amplification of the ITS-1 fragment of the insect’s rDNA by PCR. The DNA concentrations, ranging from 0.14~1.6 ng/20mL, were given a clear amplicon’s pattern after PCR amplification. This result will be available for fruit fly identification.
The isolates of the oriental fruit flies were collected from fifteen counties/cities and examined by RAPD-PCR with four selected primers (UBC-431, 91167, 91074, and OPU-09). These results were analyzed by computer with NTSYS-pc (Version 2.0) software. The isolates of the oriental fruit flies could be divided into two main groups: a northern-middle group and a southern group. The isolate collected from the eastern coast of Taiwan was more closely related to the former group.
Maize weevils collected from ten representative storehouses in Taiwan were examined by RAPD-PCR with four selected primers (UBC-431, OPU-11, OPAC-02, and OPAc-12). The amplicons were analyzed by computer with NTSYS-pc (Version 2.0). These weevils fell into two main groups (western and eastern) and six minor groups. This result is coincident with the geographic distribution of maize weevils. Five isolates of rice weevils were examined by RAPD-PCR with four selected primers (UBC-431, OPU-05, OPAc-02, and OPAC-10). The amplicons showed two main groups (western and eastern) after computer analysis.
|
|---|
