Morphological And Genetic Characteristics Of Brevipalpus Lewisi (Acari: Tenuipalpidae) And Comparison With Other Three Brevipalpus Species

The flat mite, Brevipalpus lewisi McGregor was recently found infesting Metasequoia glyptostroboides Hu & Cheng (Taxodiaceae) in China. In order to accurately differentiate this species from other closely related Brevipalpus species and appropriately apply prevention and control strategies, this study focused on morphological description and identification of adults based on electron microscopy and molecular sequencing of the mitochondrial cytochrome oxidase subunit I gene. Morphological analyses showed significant differences and similarities between B. lewisi (McGregor), Brevipalpus phoenicis (Geijskes), Brevipalpus californicus (Banks) and Brevipalpusobovatus Donnadieu in the number and/or quality of dorsal setae, omega on tarsus II, dorsal cuticular patterns and leg chaetotaxy. Phylogenetic analyses of mitochondrial CO I gene fragment (342 bp) indicated B. lewisi is 86% homologous with the other three species. The genetic distance between B. lewisi host-associated populations of M. glyptostroboides and Vitis vinifera (Vitaceae) is 6.7%, suggesting the existence of genetic divergence between hosts.