Taxonomics And Phylogeny With Cladistic Analysis On The Higher Taxa Of Phytoseiid Mites From China (Acari: Mesostigmata, Gamasina)

The family Phytoseiidae is one of great groups of Phytoseioidea which distributed worldwide. They are free living in various inhabitation and plants. There are 70 genera in taxonomic scheme of the family accepted at present. Phytoseiid mites are important and useful predatory natural enemies to control many pest mites and small insects.The present dissertation mainly deals with the morphology, taxonomy, phylogenetic analysis of Phytoseiidae from China. Totally 3 subfamilies, 9 genera and 56 species are treated in the taxonomics. The phylogeny of the family at generic level is analyzed based on the morphological characteristics and molecular data separately. Keys to the subfamily, genera and species known from China are given for identification in the paper.The phylogenetic relationships among 10 genera within the family Phytoseiidae, with the genera Otopheidomenis as the outgroup, from China, were analyzed with 23 morphological characters using computer cladistic program Paup*4.0 and Henning86. The phylogenetic tree indicated that the genera Amblyseius and Iphiseius; Okiseius and Paraphytoseius are sister groups. However, relationships among other genera proposed that the present classification scheme of genera is not closed to nature, although it is still remained to further study with more information from morphology and bionomics.Mites have usually been identified by their morphological characters. However, morphological evidences are not always sufficient to distinguish between closely related species, and to construct phylogeny among taxa for making systematic scheme close to the nature, leading taxonomists to consider additional ecological, biological and, more recently, molecular characters in this process. Molecular identification could enhance our abilities to understand evolution in the group and monitor the species during rearing and after release into the field. Hence, ITS and Mt 12S rRNA gene were amplified, cloned and sequenced. Clustal W alignment of the Mt 12S rRNA gene sequence of the three species (A.nicholsi,A.largoensis and E. nicholsi) and other four found in GenBank are made to reconstructe phylogenetic tree for phytoseiids. The phylogenetic tree indicated that the genera Neoseiulus and Phytoseiulus are sister groups.The result shows that the present classification scheme seems agreeable to the relationships revealed in the phylogenetic trees among 3 subfamilies. The study indicates that they are 3 monophyletic groups.Due to sequence information of the genes available in GenBank are still lack in constructing convincible phylogenetic tree for phytoseiids, more basic work on sequencing is urgently required for molecular systematics of the family.