A new species of plant mite (Acari: Eriophyidae) was discovered on medusahead (Taeniatherum caputmedusae), an annual grass that is native to central Asia and the Mediterranean Basin. It is invasive in western North America. Aculodes altamurgiensis sp. nov., is described here and differentiated from other Aculodes spp., on the basis of morphology. Its DNA fingerprinting was reported and compared with Aculodes mckenziei collected from Elymus repens and Bromus inermis. Pairwise comparison of MT-CO1 sequences between A. altamurgiensis sp. nov., and A. mckenziei revealed 20.2–21.5% genetic divergence between these congeneric species. First collected in Parco Nazionale dell'Alta Murgia in Apulia, Italy in 2014, A. altamurgiensis sp. nov., has been subsequently collected from medusahead in Serbia, Bulgaria, Iran and Turkey. Based on these data and on preliminary observations on the effects of the mite on plant growth, A. altamurgiensis sp. nov., is currently being investigated as a candidate biological control agent of medusahead.

Two new species of oripodoid mites (Oribatida: Oripodoidea) are described from soil of the Oumé region in Côte d'Ivoire. Scheloribates oumensis sp. nov. (Scheloribatidae) differs from all species of the genus by the presence of strong longitudinal ridges on prodorsum. Gephyrazetes ndrii sp. nov. (Mochlozetidae) differs from Gephyrazetes umukusumae Ermilov & Starý, 2018 by the presence of ten pairs of notogastral setae and spindle-form bothridial setae. An identification key to known species of Gephyrazetes is presented.

Fungitarsonemus Cromroy is a genus of Tarsonemidae (Prostigmata) that is easily recognizable by the shape of its pharynx and length of the scapular setae of both sexes. Fourteen species have been described worldwide. Here, we describe Fungitarsonemus australiensis sp. nov. from citrus in Australia. A key to the species of Fungitarsonemus from Oceania is provided.

Two new species of myrmecophilous mites of the superfamily Pygmephoroidea (Acari: Heterostigmatina) are described from ants collected in dry cacao fruits in a plantation in Ilhéus, Bahia, Brazil. Petalomium braziliensis sp.nov. (Neopygmephoridae) from workers of Odontomachus haematodus (Linnaeus, 1758), and Caesarodispus delabiei sp.nov. (Microdispidae) from workers of Camponotus atriceps (Smith, 1858) (Hymenoptera: Fomicidae). This is the first record of the genus Caesarodispus in South America.

The morphological ontogeny of Hafenrefferia gilvipes (C.L. Koch, 1839) is described and illustrated. The juveniles of this species are unpigmented, and have most gastronotal setae long, and the nymphs carry the exuvial scalps of previous instars, using mainly seta c₂. This seta is curved posteromedially and covers these scalps, representing a new manner of fastening of exuvial scalps to the mites' body in eupheredermous. The larva has 12 pairs of gastronotal setae, the nymphs have 12 pairs; the latter also have a small posterior excrescence, with a long, setiform and dorsally raised seta h₁.

A new species of the genus Meristolohmannia (Oribatida: Lohmanniidae) is described from litter of a secondary forest in Macao of southern China; M. macaoensis Ermilov sp. nov. differs from M. abbreviata Chen, Yang & Xie, 2010 by the comparatively longer rostral setae than the lamellar, interlamellar and posterior exobothridial setae, bothridial setae with well-developed branches, reticulate notogaster surface, number and morphology of subcapitular setae, nine pairs of genital setae and the smaller body size. An identification key to the known species of Meristolohmannia is provided. Lohmannia (Lohmannia) corallium Nakatamari, 1982 is recorded in the Oriental region for the first time; its supplementary description is provided based on material from China, and the revised diagnostic traits for this species are also proposed.

A new phytoptid genus and two new species, Solenocristus karooensis n. g. & n. sp. and S. searsius n. sp. (Phytoptidae, Sierraphytoptinae, Sierraphytoptini), were collected in the Eastern and Western Cape provinces of South Africa, from southern African endemic dicotyledonous trees Schotia afra (Fabaceae) and Searsia lucida (Anacardiaceae) respectively. They are described and illustrated with the aid of conventional light microscopy and low temperature scanning electron microscopy. Females of both new species possess a distinct pregenital plate divided into two parts by a subcuticular medial ridge. Additionally, in S. karooensis n. sp. the movable digit of the male chelicerae varies in length: among six observed males, three males had a movable digit (md) twice shorter than the fixed digit (fd), in one male it was slightly shorter than fd and in the remaining two males md and fd were of the same length. An updated key to the world genera of the tribe Sierraphytoptini is given. The key incorporates data on seven sierraphytoptine genera including three genera (Neoprothrix Reis & Navia, Solenoplatilobus Chetverikov & Craemer and Solenocristus n. g.) which were described since the last generic key of Eriophyoidea by Amrine et al. (2003) was published.

The tick Dermacentor everestianus is widely distributed in Qinghai-Tibet Plateau of China and can transmit many zoonotic pathogens. In the current study, the complete mitochondrial (mt) genome of D. everestianus was sequenced through Illumina HiSeq sequencing. The mt genome is 15,191 bp in length which contains 37 genes, including 13 protein-coding genes, two ribosomal RNA genes and 22 transfer RNA genes. The overall GC content reached 21.20%, whereas the GC content in the gene region was 21.40%, and in the intergenetic region was 20.50%. Two control regions were sequenced from mt genome of D. everestianus, one located between tRNA-Cys and tRNA-Leu, and the other one was found between rrnS and tRNA-Ile. Two tandem repeats were found between tRNA-Glu and nad1. A phylogenetic tree was constructed based on the complete mitogenome of D. everestianus and 32 other ixodid tick mitogenomes to assess their phylogenetic relationships. D. everestianus is phylogenetically clustered with the tick D. silvarum and D. nuttalli. This is the first complete mt genome of D. everestianus, which provides a useful reference for future studies on systematics and population genetics of this tick species.

Mite identification is usually done by the examination of morphological characteristics, the variation of which is not always sufficiently known to allow reliable distinction between closely related species. Morphological variations can be associated with geographical distribution and/ or with host ranges. The objective of this study is to evaluate the morphological variations of a population of a predatory mite identified as Euseius concordis (Chant) (Phytoseiidae) collected in Piracicaba, southeastern Brazil, when reared at different combinations of temperatures (20°C or 28°C) and diets (pollen of Typha domingensis Pers or the eriophyid mite Aceria litchii (Keifer)). High variations were observed even among mites of each treatment. Temperature (especially) and diet caused significant changes in the dimensions of some structures. Extreme cases corresponded to the maximal lengths of the dorsal idiosomal setae z2 and z4, which were about twice their minimal lengths. It is argued that for practical taxonomic purposes, it is more relevant to determine the range of the variation of each structure than its mean or other statistical parameters describing populational variations.

Typhlodromus (Anthoseius) ornatus Denmark & Muma (Acari: Phytoseiidae) is one of the predatory mites associated with the coconut mite Aceria guerreronis (Acari: Eriophyidae), a serious coconut pest in Africa, Asia and America. Vegetable oils such as coconut oil have been shown to efficiently control A. guerreronis, however their side effects on predatory mites remain poorly investigated. Here, we evaluated the lethal and non-lethal effects of coconut oil on repellence and functional response of the predatory mite T. ornatus, a natural enemy of A. guerreronis. Based on LC₅₀ estimates, coconut oil was over 6-fold less toxic to T. ornatus than to its prey, A. guerreronis. Additional repellence and predation bioassays show that the coconut oil neither repels nor interferes in the functional response of T. ornatus preying upon A. guerreronis. According to our selectivity approach, the coconut oil is compatible with the predatory mite T. ornatus.

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is a well-known pest mite with an extensive host range worldwide. The control of T. urticae populations mostly relies on the application of synthetic acaricides or pesticides. Chlorfenapyr is a broad spectrum insecticide/miticide effective against agriculturally important pests. In this study, sublethal effects (LC₁₀, LC₂₀ and LC₃₀) of this insecticide on demographic parameters of T. urticae based on the age-stage, two-sex life table theory were investigated under laboratory conditions [25 ± 2 °C, 60 ± 5 % RH and 16:8 (L:D) h]. According to the obtained results, the LC₅₀ value for females of T. urticae was 47.66 ppm. The egg incubation, protonymph, as well as deutonymph durations of both sexes were significantly reduced as a consequence of treatment with LC₂₀ and LC₃₀ of chlorfenapyr. In addition, our results indicated that oviposition period in LC₁₀ lasted 9.62 days, which was closer to the control (9.73 days); while it significantly decreased with increasing the concentration from LC₂₀ to LC₃₀. Furthermore, LC₂₀ and LC₃₀ treatments decreased the fecundity of females by 55.5% and 61.6%, respectively. The values of both intrinsic (r) and finite rates of increase (λ) at LC₂₀ and LC₃₀ was significantly inferior to other experimental treatments. It could be concluded that along with the lethal doses, the sublethal concentrations of chlorfenapyr profoundly reduced the population growth rate of T. urticae.

A new species of the genus Tenuipalpus, T. pariae sp. nov., is described and illustrated based on female, male and immature stages, collected from leaves of caper bushes, Capparis sp. (Capparaceae) from Gamasiab, Nahavand, Hamedan Province, Iran. A key to all known Iranian species is provided.

Two new species of Angulobaloghia Hirschmann, 1979 were discovered in Brunei. Angulobaloghia bruneiensis sp. nov. differs from the congeners in the following unique character combination: sternal setae St1–St3 wide and robust and genital shield of female subtriangular with long anterior process. The second species, Angulobaloghia pallgergelyi sp. nov., has long and triangular genital shield covered by large oval pits in the female and long setae V7 and V8 in the both gender, which is also unique character combination within the genus Angulobaloghia. A new diagnosis of the genus Angulobaloghia and a new key to the known Angulobaloghia species are given.

This comprehensive review of host-parasite associations between larval Trombidioidea and its arthropod hosts includes 676 pair-wise (species-species) associations and is based mainly on published records, supplemented with new findings. For 27% of all nominal species assigned to the superfamily (excl. Trombiculidae and Walchiidae), and for 66% of species known from larvae at least one host record has been hitherto provided. Hosts remain unknown for Allotanaupodidae and Yurebillidae. Both generalist and specialist parasites have been recognized within Trombidioidea. However, for the vast majority of species, the fragmentary data on host-parasite associations do not allow differentiation between common and exceptional hosts, apart from general preferences towards the host group. Hitherto recorded arthropod hosts, exploited by trombidioid larvae, are listed. Ecological data relating to measures of host-parasite interactions are summarized. Names of mites and their hosts are verified and updated and the recent affiliation to higher taxa is followed.