A fenvalerate-resistant strain of Amblyseius pseudolongispinosus Xin, Liang & Ke was selected and evaluated for level of resistance. After 18 selection cycles, the LC₅₀ value was 65 times higher than in wild-type strain. Resistance was partially lost if the selection pressure was removed. Genetic studies indicated that the resistance factor was controlled by a single, incompletely dominant gene. The resistant strain, which had the same intrinsic rate of increase as the wild-type strain, might be a useful biological control agent of spider mites in an IPM system.

Random amplified polymorphic DNA (RAPD) has been recently used in detecting genetic variation in insect populations. Here, we describe the use of RAPD-PCR for the study of tick DNA polymorphism. A primer “P_z” with the sequence of CGGCCCGGTA was found to be able to amplify the genome of Boophilus microplus (Canestrini). The pattern of the bands were reproducibly obtained and consisted of 13 discrete DNA fragments with the size of 1290, 1070, 960, 870, 790, 720, 630, 580, 500, 450, 390, 300 and 220 base pairs. The RAPD-PCR, for its simplicity, rapidity, and ability to reveal variation at the DNA level, is an additional taxonomic tool for the study of ticks.

Using SDS-PAGE and Western blot techniques, the common antigenic components between Ixodes sinensis Teng and Haemaphysalis bispinosa Neumann were analysed. The results showed that the salivary gland extracts of I. sinensis and H. bispinosa respectively showed 24 and 22 proteins and protein subunits in SDS-PAGE pattern. There were 6 main bands of I. sinensis with their molecular weights: 142, 105, 94, 66, 64 and 58 kDa. There were 5 main bands of H. bispinosa with their molecular weights: 215, 114, 105, 66 and 52 kDa. The number of proteins bands of I. sinensis and H. bispinosa were recognized by the sera of rabbits infested by I. sinensis and the sera of rabbits infested by H. bispinosa. Using Western blot, the common antigen band (105 kDa protein band) was discovered. It was concluded that the immune response in hosts infested by these two ticks stimulated the production of antibodies which showed cross immune reaction and the 105 kDa protein antigen might be the common antigen of two tick species.

The effectiveness of biocontrol of Panonychus citri with Stethorus punctillum in citrus orchards can be enhanced in two ways. One is by double releases to raise the number of S. punctillum, with the first release in mid May and the second in mid September. The other is by planting alternative host plants in a citrus orchard to provide a refuge for S. punctillum and enable it to survive the food crisis in autumn. The main kinds of alternative host plants and the associated species of leaf mites were investigated around Guiyang City. A plan to design a system of alternative host plants of S. punctillum in a multiple-species citrus orchard system is put forward.

Tetranychus kanzawai Kishida (TKK) is an important injurious mite in open-air strawberry gardens in southern China, affecting both the quality and quantity of strawberry crop. Laboratory studies showed that adult females of Phytoseiulus persimilis Athias-Henriot could consume 4–5 TKK females per day, whereas adult males and nymphs could consume 2–4 TKK females. Studies on predator responses to prey density revealed type II functional responses for both adult and deutonymph predators. Studies on predator response to its own density revealed that per capita attack rate (A) decreased with predator density (P): A = 9.539 P-0.698 (r = -0.988). Laboratory studies showed that predator and prey (N) dynamics could be described by the Lokta-Volterra model: dN/dt = N (0.111 0.898 P) and dP/dt = P (-0.138 0.023 N). Field observations showed that release of two predators per plant in mid March provided effective control of TKK during the rest of the growing season.

This paper reviews various aspects of the biology of Allothrombium ovatum Zhang & Xin (Acari: Trombidiidae) in Shaanxi, China, including life history, overwintering, adult feeding behaviour and range, oviposition, post-embryonic development, larva-host relationships and population dynamics. The use of A. ovatum larvae in the biocontrol of Aphis gossypii is discussed.

Cultures of Drosophila (Diptera: Drosophilidae) and Drosophila parasitoids (Hymenoptera: Cynipoidea, Eucoilidae) in the Department of Biology, Imperial College at Silwood Park, England were infested by Proctolaelaps (Proctolaelaps) sp. near scolyti Evans. Mites were brought under control in 6–8 weeks by three measures: (1) fly culture bottles were sealed with non-absorbent cotton wool bungs, (2) infested bottles were immediately destroyed, and (3) emerging flies and parasitoids were screened for mites before they were used for further culturing. Experiments showed that mites could not survive and reproduce on a diet of water or Kalmus medium, but could on Kalmus medium with Drosophila larvae, on live yeast, on Kalmus medium with yeast, or on Kalmus medium with yeast and Drosophila larvae. Predation on Drosophila eggs, larvae and nymphs by Proctolaelaps was not observed, nor was a decline in the productivity of fly culture after heavy infestation with Proctolaelaps. This mite is likely to be fungivorous and might be a competitor/predator of acarid contaminants in fly cultures.

The biology of Typhlodromus athiasae Porath & Swirski (Acari: Phytoseiidae) was studied in the laboratory. When mites were fed on pollen of Carpobrotus edulis highest fecundity (1.5 eggs/day for 20 days) was obtained at 25°C, 70% RH and a photoperiod of L:D 16:8; lower or higher temperatures and humidities resulted in lower fecundity. Feeding on a spider mite, Tetranychus urticae Koch, resulted in a similar number of progeny, but apple pollen engendered less progeny. Fewer eggs were produced at L:D 10:14 than at L:D 16:8. Individual males fertilized an average of six virgin females. Presence of males with females throughout the 20 days of oviposition did not induce higher fecundity than a one-day male-female co-occurrence. The sex ratio was M:F 1:2.6. Virgin females which mated late in their lives (at 30, 60, 90 and 120 days post-emergence) produced progressively fewer eggs, and for a shorter period, than early-mated females. At 25°C some females lived for 3–4 months after oviposition, but no such prolonged survival occurred at 21°C or 29°C. Larval mites molted without feeding. These findings are discussed in relation to theories about the evolution of phytoseiid life histories.

Three aspects of aphid host selection by parasitic larvae of Allothrombium pulvinum Ewing (Acari: Trombidiidae) were examined using two-choice tests in the laboratory. Seven aphid species were studied for host selection by larval mites: Cryptomyzus alboapicalis (Theobald), Liosomaphis berberidis (Kaltenbach), Macrosiphum rosae L., Myzus ornatus Laing, Myzus persicae (Sulzer), Periphyllus testudinaceus (Fernie), and Dreoanosiphum platanoidis (Schrank). In host species selection tests, larval mites preferred M. persicae to M. ornatus, which was as attractive to the mite parasites as M. rosae. Larval mites preferred M. rosae to C. alboapicalis. Aphidinae as represented by M. persicae, M. rosae or C. alboapicalis was more preferable to the mite parasites than P. testudinaceus of the Chaitophorinae, which was as attractive as D. platanoidis of the Drepanosiphinae. In host size selection tests, significantly more mites selected the large host than small host of L. berberidis and D. platanoides. The large and small hosts of P. testudinaceus, M. persicae and M. rosae were similarly attractive to larval mites. The size of the host aphid affected the choice by the mite parasite between a parasitized and an unparasitized host of M. persicae and P. testudinaceus, but not of L. berberidis nor of D. platanoidis. For P. testudinaceus and D. platanoidis, parasitized large hosts had higher probabilities of being attacked further than unparasitized large host, but the pattern was reversed for small aphids. These results were discussed in light of the previous studies and hypotheses on aphid host selection by mites.

Allothrombium ovatum Zhang & Xin is an important natural enemy of Aphis gossypii Glover in cotton growing areas in the northern part of China. Its larvae are ectoparasitic on aphids during early spring. Larvae of A. ovatum in cotton fields were from two sources: the cotton field itself and the surrounding fields. Field experiments showed that most mites were from outside sources; open plots, allowing immigration of mites via A. gossypii alatae, had over 10 times as many mites as enclosed plots. Mite larvae migrated to cotton fields by parasitizing migrant alatae of A. gossypii; they moved with aphids into open cotton fields at the rate of 90.7 mites/m²/day, and into plastic film-mulched cotton fields at 36.0 mites/m²/day. Most migrant alatae (92.0%) had a mite load of one, 6.7% had a mite load of 2 and 1.3% carried 3. The maximum load of mites came to 26% of the host weight. Laboratory studies on the 3rd and 4th instar nymphs of A. gossypii showed that parasitized aphids suffered increased mortality and reduced reproductive rates.

Spatial distribution patterns and population dynamics of Tetranychus kanzawai Kishida (TKK) were studied during 1994–1995 in open-air strawberry gardens in Fuzhou, China. The study showed that eggs and active stages of TKK were aggregated during different periods and in different gardens. The Iwao's linear regression was = 5.883 + 2.009 m (r = 0. 948) for eggs and was = -20.746 + 3.007 m (r = 0.897) for active stages. The mean densities and indices of mean crowding of both egg and active stages fluctuated through time. During the whole growth period of strawberry, the densities of eggs and active stages were correlated. The populations of TKK peaked near late December and mid February and exploded towards the end of the growing season (May of the second year).

A review of relevant literature underpins a revised definition required for the Eupodoidea. Cladistic analysis of 22 taxa and 44 characters indicates that the Penthalodidae are monophyletic and the Penthaleidae are paraphyletic. The phyletic status of the Eupodidae was not resolved. The Rhagidiidae are either paraphyletic or, if Strandtmanniidae is regarded as a synonym of Rhagidiidae, monophyletic.

A cladistic analysis of relationships at the generic level was carried out for the Eriophyoidea. The analysis was based on a total of thirty-five characters drawn from the examination of investigated specimens and original descriptions of species in 17 genera examined. These characters were polarized by comparison with the generalized Tydeidae, which was chosen as the outgroup. Three equally parsimonious trees were produced using branch and bound procedure of PAUP after successive character weighting. Three distinct clades were revealed in the strict consensus tree: clade A (Pentasetacus, (Novophytoptus, Mackiella)), clade B (Phytoptus) and clade C (Trisetacus, (Nalepella, ((((Sierraphytoptus, Ashieldophyes), Phyllocoptes), ((Aberoptus, Cecidophyes), (Nothopoda, Eriophyes))), (((Diptacus, Diptilomiopus), Rhinophytoptus), Rhyncaphytoptus)))). The Phytoptidae is paraphyletic, whereas the Eriophyidae ( Sierraphytoptinus) and the Diptilomiopidae are both monophyletic. The current classification systems within the Eriophyoidea are appraised, with suggestions on further study on the phylogeny of the superfamily, and on the revision of the classification systems to reflect the natural relationships at the familial and generic levels.

Echinopsis fukiensis gen. nov. et sp. nov., collected under longan (Euphoria longana) bark from Fujian, P. R. China, is described. A key to the genera of the Xenocaligonellidae is provided.

Abrolophus neobrevicollis Zhang & Goldarazena sp. nov. (Acari: Erythraeidae) is described from a larva parasitic on Chirothrips aculeatus (Thysanoptera: Thripidae) from Spain. The genus Grandjeanella (Acari: Erythraeidae) is reported for the first time from Asia and Europe. Grandjeanella multisetosa s p. nov. Zhang & Goldarazena is described from larvae parasitic on Thrips tabaci and other thrips from Spain. Grandjeanella bella Zhang sp. nov. is described from a larva parasitic on Sericothrips from Iran. Published records of larval Erythraeidae parasitic on thrips are reviewed. A revised generic definition of Grandjeanella is proposed and a key to species of Grandjeanella is provided.

Korcak's power law is applied to examine the patchiness of distribution of taxonomic richness, using data from the Oribatida as an example. The power law [N (n) = A × n^B, where N (n) is the number of taxonomic units with at least n subunits] provides adequate descriptions of the distribution of taxonomic richness at a variety of scales in the Oribatida. The variation of the Korcak's exponent B across taxonomic scales is examined and its value as a measure of patchiness of distribution of taxonomic richness is discussed.

A review of the sand mite genus Multisetosa Hsu et Wen, 1963 (Acariformes: Leeuwenhoekiidae) was made. According to updated records of 20 species and a subspecies from CIS, China, Iran and Mongolia, the generic characters were revised. Six species-groups were proposed tentatively by the author and a key to the known species of the genus was given.

The larva, deutonymph and adult of Trombidium southcotti sp. nov. (Acari: Trombidiidae) are described from Iran. Larvae were reared from eggs in the laboratory. This is the seventh species of Trombidium that is described from both larval and post-larval stases.

Males and females of Pyemotes moseri sp. nov. are described. This mite is a parasite of the larva and pupa of a species of Cryphalus (Coleoptera: Scolytidae) infesting Chinese hickory in Hebei, China.

Two new species of the genera Neotarsonemoides and Xenotarsonemus are described. Neotarsonemoides triquetrus sp. nov. was found on pine needles on the ground. Xenotarsonemus ligula sp. nov. was collected in samples of mosses on a tea tree. Types were deposited in the Collection of Plant Protection Research Institute, Fujian Academy of Agricultural Sciences, China.

The present work lists seventeen species of the genus Macronyssus (Acari: Macronyssidae) from China, including descriptions of two new species, Macronyssus emeiensis sp. nov. and M. fujianensis sp. nov. A key to described species of Macronyssus of China is provided. The generic characters of Macronyssus are revised and three species-groups in this genus are tentatively recognized.

Four new species of the subfamily Hypoaspidinae (Acari: Laelapidae) collected from moss are described from Anhui, Zhejiang, and Shanghai, China. They are H.(Cosmolaelaps) postreticulatus sp. nov., Hypoaspis (Geolaelaps) reticulatus sp. nov., H. (Cosmolaelaps) hefeiensis sp. nov., and Pseudoparasitus (Gymnolaelaps) submyrmecophila sp. nov.

A new genus and species of the otopheidomenid mite, Orthopteroseius sinicus gen et sp. nov. is described for specimens off hosts, Elimaea punctifera (Walker) and Hexacentrus mundus (Walker), from Hong Kong and South China. The new mite is the second species in the family Otopheidomenidae found in the tracheae of orthopteran insects.

Knorella thailandica nom. nov. is proposed for Knorella bambusae Chardrapatya. A key to world species of the genus Knorella is provided.

Larvae of Allothrombium triticium Zhang (Acari: Trombidiidae) are newly recorded as ectoparasites of the pupae and adults of Coccinella septempunctata L. (Coleoptera: Coccinellidae) from Kalardasht, Iran. Host associations of Allothrombium larvae are reviewed and host specificity is discussed.

Allothrombium pulvinum Ewing is newly recorded from Spain. The larval specimens were collected from the leaves of Dipsacus fullonus in association with more than 100 specimens of Myzus sp. (Homoptera: Aphididae). Metric data of larvae are given and comparisons with the data of specimens from Iran and China are presented.

Psorobia bos Johnston (Acari: Psorergatidae), the cattle itch mite, is reported for the first time from the Palaearctic region. This is also the first record of the genus Psorobia occurring in the British Isles. The ventral aspect of the female is figured for the first time and the British specimen is described.