A new species of the genus Scapheremaeus (Oribatida, Cymbaeremaeidae)—S. marati sp. nov.—was collected from bark of different trees in Cat Tien National Park, southern Vietnam, is described based on adult and juvenile instars. The identification keys to known adults of Scapheremaeus from the Oriental region, as well as to larvae and nymphs of known scapheremaeid species are presented.

Ten Opilioacaridae species from the genera Caribeacarus and Neocarus are found in subterranean habitats in Brazil, and several new species are waiting to be described. As part of our studies on cave opilioacarid species, two new species from Peruaçu Caves National Park, Minas Gerais state, are described in the present paper. The two new species present six or more d type setae on the palp, with a stout and rounded lobe: Neocarus chimera sp.nov. with 6 to 9 setae and Neocarus peruassu sp.nov. presents 6 or 7 foliate setae (d1). The combination of these characters is a transitional state observed between Neocarus (4 to 9 foliate d type setae on palp, with a stout and rounded lobe) and Caribeacarus (8 to 12 foliate d type setae on palp, with a fine and pointed lobe). The systematic position of the new species is briefly discussed. Additionally, the habitat description and some ecological notes are provided for both new species.

A report of our earlier study described a phytoseiid mite Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) release system using a moisturized sheltered sachet for spider mite control. For the present study, we installed the predator release systems on 43 out of 71 trees in a Japanese pear orchard to survey the dispersal of N. californicus released from the predator release system. In the orchard, Japanese pear trees were trained on the overhead horizontal trellis system. Consequently, the trees were mutually connected through the trellis training system. We collected phytoseiid mites on the tree leaves and were subjected to PCR to examine their species composition. Results demonstrated that N. californicus were 62.37% of the total of 3,247 phytoseiid mites collected. Using microsatellite markers, commercialized N. californicus that had been released from the predator release systems were discriminated from indigenous N. californicus. Results demonstrated that phytoseiid mites consisting mainly of the commercialized N. californicus occurred one week earlier in trees with the predator release systems. Results also demonstrated that the commercialized N. californicus dispersal occurred mainly in trees installed with the predator release systems.

Tetranychus macfarlanei is a potential threat to various economically important crops. Chemical control is widely used to control this spider mite, but the exclusive reliance on chemical acaricides is now being questioned, and entomopathogens are emerging as a promising alternative. The efficacy of the entomopathogens largely depends on abiotic factors like temperature, humidity, rainfall etc. The experiments were conducted to determine the effect of relative humidity on the efficacy of the entomopathogen Beauveria bassiana (strain GHA), marketed as BotaniGard ES, against the adult female and egg stages of T. macfarlanei under laboratory conditions. Adult females and eggs of T. macfarlanei were treated with three concentrations of BotaniGard (1×10⁶, 1×10⁷, and 1×10⁸ conidia/ml), and virulence was assessed on mites held at three relative humidity levels (55, 75, and 95 ± 2% RH) at 25 ± 1 °C. The results showed that the mortalities of adult females and eggs of T. macfarlanei were dose-dependent, and there is certainly a synergistic effect of relative humidity on the efficacy. When the eggs were treated under the above laboratory conditions, highest egg mortalities of 86.4 and 91% were recorded at a concentration of 1×10⁸ conidia/mL at 75 and 95 ± 2% RH, respectively, after six days of treatment. The LT₅₀ values on adult females were 28.7 h and 33.4 h at 95 and 75 ± 2% RH in a concentration of 1×10⁸ conidia/ml, respectively, which was significantly lower than values for other concentrations and RH levels. This study identified 1×10⁸ conidia/ml of B. bassiana at 75 to 95 ± 2% RH as the best possible combination than other lower RH to manage the spider mite.

Laelapine mites are one of the most common ectoparasites of cricetid rodents. The taxonomical status is unclear of mites reported as Laelaps manguinhosi-like mites, since morphological variation was reported within the species in association with taxonomically and ecologically distinct sigmodontine rodents. We analysed morphological (qualitative and metric variation) and molecular data of four morphotypes of L. manguinhosi-like mites collected from three sigmodontine rodents (Cricetidae) of the tribe Oryzomyini (Holochilus brasiliensis, Nectomys squamipes and Oligoryzomys flavescens) and one of the tribe Akodontini (Scapteromys aquaticus). For better understanding, we defined L. manguinhosi sensu lato as a species concept and limited in a narrower sense L. manguinhosi sensu stricto. The association known from the literature between L. manguinhosi sensu stricto and H. brasiliensis was confirmed and additional information of this mite was provided. Mites associated with the remaining rodent species appear to be new species within L. manguinhosi sensu lato species complex, here described as Laelaps galliarii sp. nov., Laelaps scapteromyos sp. nov., Laelaps odysseos sp. nov., parasitizing O. flavescens, S. aquaticus and N. squamipes, respectively. Morphological analysis showed clear separation between the four studied species, with the majority also supported by molecular data. These results reinforce previous observations that Laelaps species are specific at least to the level of the host genus. Phylogenetic analysis based on 18.S-ITS1-5.8S-ITS2 partial gene markers indicate an earlier host-switch scenario between an akodontine associate (L. scapteromyos sp. nov.) and an oryzomyine associate (L. manguinhosi sensu stricto) followed by cospeciation events. Studied morphotypes of Laelaps were resolved as three separated clades. The basal one included mite species associated exclusively with Murinae (Old World) rodents and the other two are specific to Sigmodontinae (New World). The clade of sigmodontine associates was further divided into a cluster of mites parasitizing semiaquatic rodents and another cluster comprising mites parasitizing scansorial rodents. The obtained topology indicates that both, the phylogeny of rodent hosts and their ecological traits may play an important role in the coevolutionary process of host-mite relationships.

In the paper, we present ptyctimous mite species collected from Norway, Spain, France, Italy, India, and South Korea. Two new species, Acrotritia quasiparadikra Niedbała sp. nov. from India and Phthiracarus paralentulus Niedbała sp. nov. from South Korea are described. In addition, we provide the supplementary descriptions of ten species belonging to six genera, i.e., Austrotritia dentata Aoki, 1980, Acrotritia furcata Bayoumi et Mahunka, 1979, A. koreensis (Mahunka, 1997), Microtritia minima (Berlese, 1904), Phthiracarus clemens Aoki, 1980, P. crenophilus Willmann, 1951, P. similis Niedbała, 1981, Steganacarus (Steganacarus) carusoi Bernini et Avanzati, 1989, S. (S.) doumandji Niedbała, 1986, and Austrophthiracarus maritimus (Pérez-Íñigo et Pérez-Íñigo, 1996). We also include information and comments on the distribution of investigated species.

Two new species of the genus Steneotarsonemus Beer, 1954 namely Steneotarsonemus kharukiae Karmakar & Ganguly sp. nov. and Steneotarsonemus mohanasundarami Karmakar & Ganguly sp. nov. are described based on the specimens collected from northern hill zone of West Bengal. Steneotarsonemus kharukiae was collected from Capioedium assimile and closely resembles S. comosus and S. vasiljevae. Steneotarsonemus mohanasundarami was collected from Oplismenus sp. and closely resembles S. stipa and S. hippodromus.

Water mites (Hydrachnidia) are good model organisms for the assessment and long-term monitoring of the biological impacts of natural and human-induced environmental changes in freshwater ecosystems, including those related to global climate change. However, monitoring programs using water mites as bioindicators may be impeded by difficulties associated with species identification. Here we integrate conventional morphology, DNA sequence data (using the COX1 barcoding locus) and extensive voucher photo documentation to create and validate a tool for accurate species identification of water mites in Western Siberia (including a dedicated reference climate monitoring and research site). Using this approach, we detected a total of 95 species, of which, one was a conventional new species; 14 taxa were cryptic species having large among-species COX1 K2P distances but lacking any apparent morphological differences. Our a priori species delimitation was successfully validated a posteriori. An automatic species delimitation algorithm (ASAP) identified exactly the same set of 95 species, with a species delimitation threshold of 6.1%. This result agrees with previous works suggesting a large threshold of 5.6–6.0% for water mites, but contrasts with the BOLD approach which uses a much lower threshold to identify BINs (1%). Furthermore, by comparing our identified sequences with GenBank data, we expanded known geographic ranges of several water mite species. Using extensive GenBank data on mites in Canadian waters, four species were detected to be Holarctic rather than Palaearctic as thought previously (Lebertia obscura, Limnesia undulatoides, Oxus nodigerus and Arrenurus papillator). Four species, Lebertia obscura, Torrenticola brevirostris, Hygrobates limnocrenicus and Unionicola parvipora, were recorded for the first time in Russia. We provide an annotated species checklist reporting the distribution, ecology, bioindiocation potential, and COX1 barcode sequence data along with high-resolution photographs of each DNA voucher. Future ecological and biodiversity studies will benefit from using molecular tools for accurate identification of useful mesofaunal bioindicator organisms, such as water mites.

Spider mite fauna of the genus Oligonychus Berlese (Acari: Prostigmata: Tetranychidae) was comprehensively explored from natural and cultivated vegetation in Saudi Arabia (SA), during the years 2018 to 2020. One new species, Oligonychus washingtoniae sp. nov., and three new records, O. coniferarum (McGregor, 1950), O. dactyloni Smiley & Baker, 1995, and O. tylus Baker & Pritchard, 1960, are reported for the first time from SA. The new species, O. washingtoniae sp. nov. is described and illustrated from Washingtonia filifera (Lindl.) H.Wendl. (Arecaceae). The species O. dactyloni, and O. tylus are re-described, which were briefly described previously.

The feather mite genus Lamellodectes Hernandes and Valim, 2014 (Proctophyllodidae) was originally referred to the subfamily Pterodectinae based on the crucial diagnostic feature of this subfamily—the fusion of the epigynum with epimerites IIIa in females. Detailed investigation of two Lamellodectes species collected from ovenbirds (Passeriformes: Furnariidae) in Costa Rica has shown that this genus is actually close to Platyacarus Kudon, 1982 (Proctophyllodinae). Both genera have 4 ventral setae (ra, wa, la, and s) on tarsi I and II, while other proctophyllodid genera have only 3 setae (ra, wa, la). Additionally, it was found that the fusion of epigynum with epimerites IIIa in females of Lamellodectes is incomplete, as in some representatives of the proctophyllodine genera Anisophyllodes Atyeo, 1967 and Armophyllodes Mironov and Bermúdez, 2018 that gives evidence this character state has been independently developed in this genus. Herein, the genus Lamellodectes is provided with renewed diagnosis and transferred to the subfamily Proctophyllodinae; one new species, Lamellodectes favus Mironov sp. n., is described from Premnoplex brunnescens (Sclater, PL, 1856) (Passeriformes: Furnariidae) in Costa Rica.

Essential oils have shown promising results regarding their activity on mites. However, information on mite life history is scarce. This study aimed to chemically characterize essential oils from lllicium verum, Eugenia caryophyllus, and Cymbopogon flexuosus, and to evaluate the lethal and sublethal effects of these oils on the life history traits of Tetranychus neocaledonicus André 1993. Trans-anethole and eugenol were the main components of I. verum and E. caryophyllus, respectively, and in C. flexuosus, the monoterpenes geraniol and neral stood out. Essential oils from I. verum, E. caryophyllus, and C. flexuosus showed different toxicity degrees to adults of T. neocaledonicus and decreased egg viability. All oils tested were classified as repellents for T. neocaledonicus females and caused oviposition deterrence. The survival of the parental generation of T. neocaledonicus was not affected by l. verum, E. caryophyllus, and C. flexuosus oils. However, E. caryophyllus was affected in the F1 generation. There was a reduction in the total fecundity of T. neocaledonicus compared to the parental generation. Life table parameters were affected in the F1 generation. Only the average length of a generation was decreased by essential oils in the parental generation. lllicium verum, Eugenia caryophyllus, and Cymbopogon flexuosus essential oils have lethal effects on adults and eggs of T. neocaledonicus, and exposure to sublethal concentrations affects the F1 generation of T. neocaledonicus by decreasing fecundity and altering life table parameters in this generation.