Variability of dorsal shield in different populations of Amblyseius ishizuchiensis Ehara (Acari: Phytoseiidae)

Abstract

This study provides additional morphological information and new illustrations for Amblyseius ishizuchiensis, a predatory mite species previously described from Japan, and subsequently reported from China and Russia. Our examinations on a series of specimens collected from several localities in Russia showed no remarkable difference compared to its original description and subsequent redescriptions including an almost smooth dorsal shield. However, we observed a strongly punctate dorsal shield in both sexes in the specimens originated from South Korea as well as from Anuchinsky district, Ussuri Nature Reserve, Vladivostok (Primorsky Krai) and Komsomolsk-on-Amur (Khabarovsky Krai), Russia, with other morphological characters and measurements of the specimens being almost identical to the other specimens examined in this study, as well as the earlier descriptions. Although, these specimens with smooth vs punctate dorsal shield are never found in a single population, we suggest this character as intraspecific variation on a provisional basis. Moreover, we observed that this species by having broader ventral shields, does not really fit the diagnosis of the genus Amblyseius in the subtribe Amblyseiina. Therefore, a short discussion about its generic placement in the subtribes Amblyseiina and Arrenoseiina is also provided.