Shozo Ehara

Divergence in host range and reproductive compatibility in three strains of Oligonychus gotohi Ehara (Acari: Tetranychidae)

Abstract Preliminary observations indicated that Oligonychus gotohi Ehara collected from deciduous chestnut (deciduous-tree strain) could not develop on leaves of the evergreen broad-leaved tree Lithocarpus edulis (Makino) Nakai in the laboratory. Furthermore, we found an evergreen arrhenotokous (A) strain that produces both female and male progeny and an evergreen thelytokous (T) strain that produces only female progeny. These observations suggest that O. gotohi consists of either host races or sibling species. To determine which is the case, we examined the above three strains on 19 fagaceous plant species. The deciduous-tree strain successfully developed and oviposited on seven deciduous trees but did not develop on evergreen trees at all. The evergreen-A strain had the narrowest host range and could develop and oviposit only on three species of deciduous trees and only on three species of evergreen trees. The evergreen-T strain grew well on six deciduous trees and on all but one of the evergreen trees. Thus, the three strains demonstrated host plant divergence. Malate dehydrogenase (MDH) zymograms among populations of the same strain were similar, but those from the different strains were clearly different. Inter-population crosses in the deciduous-tree and the evergreen-A strains were compatible, but the reciprocal crosses between the deciduous-tree and the evergreen-A strains produced no females, indicating that these two strains were reproductively isolated. Neither virgin females of the evergreen-T strain nor evergreen-T strain females crossed with males of either the deciduous-tree or the evergreen-A strain produced male offspring. Thus, O. gotohi contains at least three different biological entities that may be sibling species.

Three new species of phytoseiid mites (Acari: Phytoseiidae) from Japan

Abstract Three new phytoseiid mite species are described and illustrated from Japan: Transeius fulvus Ehara and Toyoshima, n. sp. and Typhlodromus (Typhlodromus) moricola Ehara and Toyoshima, n. sp. from Morus bombycis at Shimo-kuriyagawa, Morioka, Iwate Pref., Honshu, and Typhlodromus (Anthoseius) kishimotoi Ehara and Amano, n. sp. from Citrus unshiu at Kuchinotsu, Shimabara, Nagasaki Pref., Kyushu.

New records of phytoseiid mite species (Acari: Gamasida: Phytoseiidae) from Malaysia with description of a new species

Abstract Five species of the mite family Phytoseiidae are reported from West Malaysia: Phytoseius (Phytoseius) malaysianus sp. nov. is described and illustrated, and four known species are recorded for the first time in Malaysia.

Two New Species of Tetranychus (Acari: Tetranychidae) Infesting Corn in Inner Mongolia, China

Abstract Tetranychus huhhotensis n. sp. and T. zeae n. sp. are described and illustrated from corn leaves in Inner Mongolia. Tetranychus huhhotensis n. sp., assigned to Flechtmann and Knihinickis Group 4 of Tetranychus, can be separated from its allied species by having the aedeagal knob with dorsal surface distinctly emarginate centrally. Tetranychus zeae n. sp. is distinctive in Group 9 of this genus in that the aedeagal knob is minute, with anterior projection practically absent and posterior projection conspicuous, acute. Summer females of the two new species are pale greenish-yellow, while their diapausing females are pale-orange.

Two new species of Oligonychus closely related to O. gotohi Ehara (Acari: Tetranychidae)

Abstract Two new spider mite species are described and illustrated from Ami, Ibaraki Pref., Honshu, Japan: Oligonychus castaneae n. sp. from Castanea crenata (Fagaceae) and O. amiensis n. sp. from Lithocarpus edulis (Fagaceae). Both species are sibling species of O. gotohi Ehara; O. castaneae n. sp. and O. amiensis n. sp. are designated the “deciduous-tree strain” and “evergreen-T strain” of O. gotohi, respectively, while O. gotohi (s. str.) is referred to as the “evergreen-A strain.”

Description of a new species of Phytoscutus (Acari: Phytoseiidae) from Kyushu, Japan

Abstract Phytoscutus japonicus n. sp., the first known member of this genus from Japan, is described and illustrated based on females collected from citrus leaves in Miyazaki Pref., Kyushu. It resembles P. acaridophagus (Collyer) in having the dorsal shield with seta J2, but differs in having the opisthoscutum with lobed striae, ventrianal shield noticeably wider than long, and leg IV with 3 macrosetae.

Correction to dorsal setal lengths of spider mites (Acari: Tetranychidae: Schizotetranychus) from Malaysia described by Ehara.

Abstract Incorrect measurements of the dorsal body setae of four spider mites described as new in Ehara and Tho (1988) are corrected here. The species are Schizotetranychus kochummeni Ehara, S. approximatus Ehara, S. laevidorsatus Ehara and S. saitoi Ehara. In addition, the erroneous body size of S. saitoi described in the article is also corrected.

Description of a new Eotetranychus from Japan with notes on two other species (Acari: Prostigmata: Tetranychidae).

Abstract A new spider mite, Eotetranychus toyoshimai n. sp., is described and figured from Magnolia hypoleuca Sieb. et Zucc. (Magnoliaceae) growing in Morioka, Honshu. A redescription of E. broussonetiae Wang, new to Japan, is also given based on specimens from this country. Further, Schizotetranychus shii (Ehara), n. comb. is transferred from the genus Eotetranychus.