A Study On Phylogenetic Relationships Among Braconidae (Hymenoptera: Ichneumonoidea) Based On Molecular Data And Morphological Characters

This dissertation deals with the phylogenetic relationships among the subfamilies of the family Braconidae as well as within six subfamilies (Rogadinae, Doryctinae, Opiinae, Euphorinae, Aphidiinae, and Cheloninae) of the family. It mainly consists of five chapters: the general part, material and methods, phylogenetic relationships within six subfamilies, phylogenetic relationships within Braconidae, summary and discussion.Chapter one reviews briefly the taxonomic research history, morphology, biology and phylogeny of the family Braconidae. Chapter two describes the experimental methods, experimental protocol, and softwares for phylogenetic analyses. Chapter three introduces the results of the studies on the phylogenetic relationships within six subfamilies of Braconidae. It is the first time to examine: (a) the phylogenetic relationship within Opiinae using combined data of homologous 28S rDNA D2 region, 16S rDNA and Cytb gene sequences and morphological data using both PAUP* 4.0 (maximum parsimony) and MrBayes 3.0 B4 (maximum likelihood) from 22 in-group taxa representing 10 genera; (b) the phylogenetic relationships within Rogadinae (44 in-group taxa representing 12 genera), Euphorinae (23 in-group taxa representing 19 genera), Cheloninae (9 in-group taxa representing 8 genera) and Doryctinae (16 in-group taxa representing 15 genera) using the DNA sequence of homologous 28S rDNA D2 region combined with morphological data using both PAUP* 4.0 (maximum parsimony) and MrBayes 3.0B4 (maximum likelihood); (c) the phylogenetic relationships within Aphidiinae using the DNA sequence data of homologous mitochondrial ATPase 6, mitochondrial 16S rRNA and ribosomal 18S rDNA genes combined with morphological data using both PAUP* 4.0 (neighbor-joining, maximum parsimony and maximum likelihood) and MrBayes 3.0B4 (maximum likelihood) from 23 in-groups representing 10 genera. Chapter four provides the research results on the phylogenetic relationships among the Braconidae using the DNA sequences of homologous 16S rDNA, 28S rDNA D2 region and 18S rDNA genes combined with morphological data (96 characters with different weighty sets) using both PAUP* 4.0 and MrBayes 3.0 B4 from 88 in-group taxa representing 35 subfamilies. Finally, Chapter five provides the general conclusion and discussion.The major achievements of this dissertation are as follows:1. We submitted 78 new DNA sequences of 5 genes to GenBank, covering 44 species of 29 genera of Braconidae.2. The family Braconidae is "AT" base-bias in the DNA sequences of mitochondrial genes, and transition is lower than transversion, but transition is higher than transversion in ribosomal gene sequences.3. We support that the taxonomic system of subfamily Opiinae proposed by van Achterberg (1997) is the most reasonable one among the existing three taxonomic systems of the subfamily, which could arrange the majority of genera to a reasonable taxonomic position in the system. We also found the taxa within subfamily Opiinae parasitizing on the same type of hosts are grouped into the same clade in the phylogenetic trees, indicating that the types of host utilization reflect the relationships among taxa.4. Our results showed that the division of subfamily Rogadinae into four monophyletic tribes (Yeliconini, Clinocentrini, Stiropiini and Rogadinae) is well supported, and tribe Clinocentrini occupies the basal position within the subfamily. We also found that the genus Aleiodes can be divided into four subgenera (Neorhogas, Chelonorhagas, Aleoides and Heterogamus).5. The results revealed that subfamily Cheloninae can be divided into three clades, and tribe Chelonini is paraphyletic. The validity of Cascogaster as an independent genus is confirmed while genus Microchelonus should be lowered the rank to be a subgenus of genus Chelonus.6. The three-tribe system (Ephetrini, Praini and Aphidiini) of subfamily Aphidiinae is well supported, with tribe Ephetrini occupying the basal clade. We suggested that tribe Aphidiini could be further divided into three subtribes: Monoctonina, Tr...