Systematics of the tribe Amblyseiini (Acari: Phytoseiidae) in Taiwan

Autor: Jhih-Rong Liao, 廖治榮
Rok vydání: 2011
Druh dokumentu: 學位論文 ; thesis
Popis: 99
The family Phytoseiidae is comprised of three subfamilies Amblyseiinae, Phytoseiinae, and Typhlodrominae. Up to date, more than 2300 species have been recorded. Mites of the family Phytoseiidae are famous biological control agents, which can purnish a strong contribution to agroecosystem. Therefore, phytoseiid mites had draw much attention due to their biological control potential since 1960s, and been studied extensively. In order to study, apply and monitor accurately on the appropriate species, a reliable taxonomy of Phytoseiidae is urgently needed. The current classification system is based on morphological characters, including the dorsal chaetotaxy, shape and dentition of chelicerae, shape and chaetotaxy of ventrianal shield, and macroseta on leg IV. In addition, the morphology of spermatheca is also important in the determination of species. In Taiwan, the taxonomic studies of phytoseiid mites can be traced back to 1970s. Most works were done before 1983. Fifty four species of phytoseiid mites were recorded from Taiwan. Nevertheless, there remains many works to be accomplished: 1. The survey of phytoseiid mites species were mainly carried out in agricultural areas. 2. Males of many species are still unknown. 3. Some works lack descriptions of characters and illustration considered important recently. 4. Possibility of the presence of synonyms. 5. My confidence on the existence of undescribed or unrecorded species in Taiwan. Furthermore, the phylogeny of phytoseiid mites is still not fulls resolved. This study, therefore, chose the tribe Amblyseiini, a large, species rich tribe both in the world and in Taiwan, as the first work to access Phytoseiidae. Mountain areas and offshore Islands were emphasized for collecting specimens. In addition to those characters conventionally described, the macrosetae on legs I-III, the morphology of male spermatodactyl, the setation of the ventrianal shield of adult male mites, and the coxal formula were also described. This study adds two newly recorded genera, Graminaseius Chant and McMurtry and Transeius Chant and McMurtry, five species new to science, Amblyseius curvus sp. nov., A. megadactylus sp. nov., A. neotrisetosus sp. nov., Graminaseius digitaria sp. nov., Transeius altusmontis sp. nov., Paraamblyseius jianshiensis sp. nov., and three newly recorded species, A. fletcheri Schicha, 1981, A. keni Schicha, 1987, A. wuyiensis Wu & Li, 1983 to the fauna of Amblyseiini from Taiwan. Taiwanese Amblyseiini increases from 4 genera 13 species to 6 genera 21 species after this survey. The phylogeny of the tribe Amblyseiini was also reconstructed by synapomorphic characters. The result revealed the tribe Amblyseiini is a monophyletic group, the subtribes within Amblyseiini form two clades, Amblyseiina and Arrenoseiina+Proprioseiopsina. It is congruent with the current classification system and the hypothetic phylogeny. However, the result can only explain the relationship among subtribe. The relationships among genera revelaed by current data is in polytomy. Besides, DNA-based were also performed to investigate the relationship between three closely species, Amblyseius eharai Amitai & Swirski, 1981, A. herbicolus (Chant, 1959), and A. largoensis (Muma, 1955). Two molecular markers were chosen to make the inference, mitochondrial cytochrome oxidase I (COI) and nuclear DNA ribosomal internal transcribed spacer (ITS). ITS provided better resolution than COI for inferring the relationship of related species, but the divergence were incongruent between these two genes. The results revealed these three species are monophyletic assemblages, repectively. The specimens collected with intermediate morph between A. eharai and A. herbicolus belong to A. herbicolus. Therefore, the curvature of posterior margin of sternal shiled is not a stable character for the distinguishment of A. eharai and A. herbicolus.
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