The feeding behaviour of omethoate-resistant and susceptible strains of the spider mites (Tetranychus cinnabarinus) on cowpea leaves was studied by electrical penetration graph (EPG). EPG waves of the mite feeding were divided to two forms, the high frequency (7.7–8.7 Hz) and low frequency waves (2.4–3.0 Hz), representing feeding and non-feeding behaviour respectively. The average duration of feeding periods was not significantly different between resistant and susceptible mites. However, the amplitudes of feeding waves were significantly greater in pesticide-resistant mites than susceptible mites.

Species abundance, biodiversity, distribution and population dynamics within and among oribatid mite communities were studied in rice paddies of China from October 1995 to November 1996. The Shannon-Wiener Index of Diversity and the Evenness Index indicated that the abundance and diversity of oribatids in rice paddies varied among locations and was lower than that of a typical forest ecosystem. The ability to resist environmental disturbance was low in the oribatid communities in sub-tropical monsoon areas and was more stable in monsoon temperate zones. The relative proportion of higher oribatid mites to lower oribatid mites in rice paddies is higher than that of other communities. The oribatid mites in paddy fields were mainly distributed in the upper layers of soil, which is similar to the distribution in the forest ecosystem, but the ability to distribute horizontally indicated their tendency to migrate freely within these layers. Water was an important factor allowing oribatid mites to migrate freely. The spatial distribution on rice plants indicated that mites were aggregated except there was a more even distribution in the later stages of rice maturity. Humidity and temperature, which are known to significantly affect oribatid communities in other habitats, did not significantly influence community structure on rice plants. The oribatid communities on rice was strongly affected by both mite migration and dispersion.

To characterize the epidemiology of autumn-winter type scrub typhus in a new endemic focus of Fei County, Shandong Province, China, field and laboratory studies were conducted to determine the species composition and seasonal fluctuations of chigger mites and their animal hosts. Orientia tsutsugamushi was isolated, and serotypes of antibodies to O. tsutsugamushi were detected and identified. A total of 1044 rodents and insectivores were field collected: 751 Apodemus agrarius (71.94%), 266 Tscherskia triton (25.48%), 1 Cricetulus barabensis (0.09%), 11 Rattus norvegicus (1.05%), 3 Mus musculus (0.29%), and 12 Crocidura suaveolens (1.15%). Apodemus agrarius, T. triton and R. norvegicus were shown to be naturally infected with O. tsutsugamushi. The serum antibody positive rate of rodents was 14.78%. A total of 11762 chigger mites were collected: 2547 Leptotrombidium scutellare (21.65%), 1596 L. palpale (13.57%), 466 L. taishanicum (3.96%), 2833 L. linhuaikongense (24.09%), and 4320 Walchia pacifica (36.73%). Leptotrombidium scutellare was most numerous from September to November and was the predominant species during the local scrub typhus epidemic season. Natural infection with O. tsutsugamushi was detected in L. scutellare, and transovarial transmission of the pathogen by this chigger was demonstrated. 38 strains of O. tsutsugamushi were isolated from 33 patients (14 strains), 3 species of rodents (9 strains), and 4 species of mites (15 strains). All O. tsutsugamushi strains isolated in this endemic focus were of low virulence. Serotype identification showed that 33 strains were of the Gilliam type, and 3 strains were of the Karp type. Another 2 strains remain to be identified. In the Fei County focus of scrub typhus, the main reservoir host is A. agrarius, the predominant mite vector is L. scutellare, the principal serotype of O. tsutsugamushi is Gilliam, and all strains of O. tsutsugamushi are of low virulence. Most cases of scrub typhus occurred from September to November; therefore, scrub typhus in this focus is autumn-winter type. This focus is located in the premontane flatlands of Fei County.

Development, survivorship, and reproduction of the mite Schizotetranychus bambusae Reck reared on fresh bamboo leaf were evaluated at 5 constant temperatures (21, 24, 27, 30, and 33°C). The development time from egg to adult varied from 16.7 d at 21°C to 7.6 d at 33°C. The developmental thresholds for egg, larva, protonymph, deurtonymph, pre-oviposition and combined immature stages were estimated at 12.4, 15.3, 14.0, 15.2, 10.7 and12.5°C, respectively. High temperature (33°C) engendered a decline in larval and protonymphal development. A modified nonlinear Logan model describing the relationship between developmental rate and temperature for all immature stages was constructed. Survivorship was highest (88.3%) at 27°C; whereas at 21 and 33°C, it came to 61.7 and 55.7%, respectively. After emergence the adult had a pre-oviposition period that ranged from 1.9 d at 21°C to 1.0 d at 33°C. The highest number of eggs (23.4) was produced at 27°C, the lowest at 33°C. The longest reproductive duration (15.5 d) was recorded at 21°C, and the shortest (4.3 d) at 33°C. Mites reared at 27°C had the highest net reproductive rate (15.6), whereas at 33°C they had the highest intrinsic rate of increase (0.1686). Our results suggest that S. bambusae could develop and reproduce within a wide range of temperatures.

The predatory mite Hypoaspis miles feeds on Lycoriella solani larvae (Diptera: Sciaridae) and Acarus siro (Acari: Acaridae) by cutting into the cuticle of the prey with the chelicerae. Portions of soft material are then extracted and crushed into a semi-liquid state before being sucked into the alimentary canal of the predator. H. miles has never been observed consuming sclerotized parts of the prey but sometimes kills several prey before consuming any one of them. H. miles adults were observed to survive for 7 to 8 weeks without food.

The family Trachytidae and the genus Polyaspinus Berlese 1916 are redefined, and the type species of the genus, P. cylindricus Berlese 1916, is redescribed. Polyaspinus tasmanicus sp. nov. is described from Tasmania. The previously unknown male, deutonymph, protonymph and larva of P. higginsi Camin 1954 are described from North America. P. cylindricus is thelytokous while all the other species in the genus are bisexual. A key is provided for 6 of the 7 species, and the geographical distribution and relationships of the genus are discussed.

Ameroseius qinghaiensis sp. nov. was collected from compost in Zongzhai area, Huangzhong County, Qinghai Province, China. The adult female is described and illustrated.

Variation in seven female morphological characters were examined for 18 populations of spider mites of the Tetranychus urticae and T. cinnabarinus complex from greenhouse tomatoes in various locations in the UK. Tetranychus cinnabarinus could be readily separated from T. urticae by variation in the number of setae on tibia I (10–13 setae, or addition of 1–3 solenidia normally present in males) in females and this difference was correlated with those of previously studied characters (shape of dorsal lobe in female and shape of aedeagus in male) and additional characters examined in this paper. Several populations of mites identified as T. cinnabarinus in this study were green in colour. Hyper-necrotic responses in tomato plants were present in most T. cinnabarinus populations with variation in the number of setae on tibia I but absent in T. cinnabarinus population without variation in the number of setae on tibia I (i.e. 13 setae).

Eggs and mobile immature stages of Tenuipalpus heveae Baker, 1945 are described and figured.

The genus Raphignathus from China is reviewed. The morphology of R. zhaoi Hu, Jing & Liang is studied. Four new species of Raphignathus are described: R. aciculatus Fan from moss in Fujian (southeastern China), R. membranus Fan from fallen leaves in Beijing (north China), R. evidus Fan from moss in Beijing and R. hsiufui Fan from moss in Fujian and from tea (Camellia sinensis) in Zhejiang adjecent to Fujian. A key to the known species from China is provided.

Four new species of eriophyoids collected from Arecaceae are described: Notostrix butiae sp. nov, from Butia eriospatha (Mart.) Becc.; Notostrix nasutiformes sp. nov, from Cocos nucifera L.; Knorella geonomae sp. nov, from Geonoma schottiana Mart. and Propilus syagris sp. nov, from Syagrus romanzoffiana (Cham.) Glassman.

A new species of both Xenotarsonemus and Tarsonemus are described. Xenotarsonemus biangulus Lin sp. nov. was found in bark of Metasequoia glyptostroboides Hu & Cheng, Sabina chinensis (L.), Fraxinus chinensis and mosses on bark of Ehretia thysiflora. Tarsonemus bihamus Lin sp. nov. was collected in a sample of fallen leaves on forest ground. Types were deposited in the Collection of the Plant Protection Research Institute, Fujian Academy of Agricultural Science, China.

A new larval erythraeid mite, Erythraeus (Erythraeus) shojaii sp. nov. is described from Monosteira unicostata Mulsant and Rey (Hemiptera: Tingidae) in Iran. A key to species of the subgenus Erythraeus with short anteomedian setae (AM) of the world (larva) is presented.

Erythraeus (Zaracarus) kharrazii sp. nov. and E.(Z.) rajabii sp. nov. are illustrated and described from Karaj, Iran. The key to the world species of Zaracarus is provided.

Four new species of Leptus are described: L. nikanori from plants in Costa Rica, L. filipinae from undetermined Lampyridae (Coleoptera) in Costa Rica, from undetermined Heteroptera and plants in Belize and Mexico; L. simonettae from undetermined Acrididae and plants in Guatemala and Honduras and L. onnae from plants in Mexico. A key for larvae of Leptus from Neotropical and Nearctic Regions is provided.

Leptus esmailii sp. nov. (Acari: Erythraeidae) is described and illustrated from larvae ectoparasitic on adults of Eurygaster integriceps Puton (Hemiptera: Scutelleridae) from Kermanshah, Iran.

Abrolophus welbourni sp. n. is described from Northern Michigan, USA. All instars including laboratory-reared specimens were available for study. Laboratory rearing results as well as field collections indicated that larvae previously assigned to Hauptmannia developed into deutonymphs and adults of Abrolophus.

Sand-mites comprise three families, Leeuwenhoekiidae, Trombiculidae and Walchiidae, that together constitute the superfamily Trombiculoidea sensu Wen, which is distinct from the more derived superfamily Trombidioidea. The Walchiidae contains two subfamilies: Walchiinae sensu Wen and Gahrliepiinae sensu Wen. The Gahrliepiinae may be further separated into two tribes: Gahrliepiini sensu Wen and Intermedialiini. Members of the tribe Gahrliepiini are medium to large sized, IP=500–1120. The scutum is broad tongue-shaped, in the extreme cases, covering the entire dorsum. fSc=2AL 2PL 4-28PPL. Its surface bears dense punctae, maculae or versatile scleros. The sensillae are expanded. SIF= 4B/5B/6B-N/B-3/2-2110.0000. NDV=50–240. Leg segments 7.6.6 show no variation, and are usually stumpy except in large sized genera. fcx=1.1.1 usually. The absence of paired intermedial setae (IM) in the Gahrliepiini separates this tribe from the Intermedialiini. Currently, the Gahrliepiini contains 91 named species in 8 genera and 4 subgenera, including Parvisetia g. n. and Squamulata sg. n. Almost all Oriental and Palaearctic gahrliepiine sand-mites are characterized by fT=4B, as in the genus Gateria, which may be distinguished on the basis from the Ethiopian genera Gahrliepia of 5B and Ozosetiella of 6B. Hosts of the Gahrliepiini are chiefly small ground-dwelling rodents and insectivores living in primary forests, rarely bats and birds, and never poikilotherms. Gahrliepiine sand-mites are essentially confined to the Old World, the largest number of species having been recorded from Southeast Asia. As yet, this tribe has not been reported from the Australian or Neotropical Zoogeographic Regions. An important new taxonomic index, mean dimension of coxa III, or index coxalis (IC) = (length width)/2 is introduced to differentiate genera, subgenera and species with extraordinary large coxa III. A key to genera and subgenera of the tribe Gahrliepiini is given.

In the Zoological Reference Collection, National University of Singapore there were two slides labeled as Gahrliepia myriosetosa ex Microtus kikuchii collected by E.W. Jameson from Taiwan. These two specimens have been obviously misidentified and now are regarded as the types of Gateria taiwanensis sp. nov.

Gateria myriosetosa (Wang) and Gateria chekiangensis (Chu) were redescribed in this paper. Both species were collected in the mountain area of Zhejiang (Chekiang) province, China. Re-examinations of the type specimens revealed that both are characterized by fT=4B, fp=B.B.NNB, broad tongue-shaped scutum with almost straight posterior margin, PPL as much as 19 or 24 in number and last pair of PPL marginal. The two species differ by the distribution of the PPLs on scutum, number and length of body setae.

Eutrombidium sepasgosariani sp. nov. (Acari: Eutrombidiidae) is described and illustrated from larvae ectoparasitic on Gryllus domesticus Linnaeus (Orthoptera: Gryllidae) from Ahwaz, Iran. This is the first record of Gryllus domesticus L. as a host for the genus Eutrombidium Verdun,1909. The family Eutrombidiidae is new to the fauna of Iran.

Two known species of the oribatid mite genus Epilohmannia, E. cylindrica (Berlese) and E. spathulata Aoki, are redescribed. E. cylindrica is recorded for the first time from Mongolia. Two new species, Epilohmannia spathuloides sp. nov. and Epilohmannia shtanchaevae sp. nov. are described from larch litter in Yamanashi Prefecture (Mt. Yatsugatake), Central Japan and from deep soil in the mountain-steppe landscape of Central Mongolia, respectively. A key to the Japanese and Mongolian species of Epilohmanniidae is given.