During the survey on eriophyoid mite fauna of Meshginshahr rangelands two new eriophyid species were found and described: Aceria onopordi Lotfollahi et Hemmatzadeh sp. nov. from the host plant Onopordum acanthium L. (Asteraceae) and Aculus astracti Lotfollahi et Hemmatzadeh sp. nov. from the host plant Astragalus compactus Lam. (Fabaceae). Both species were vagrant on their host plant without any observed alteration on them.

Four new species and two new records of eriophyoid mite species from Nanning, Guangxi Zhuang Autonomous Region, China are described and illustrated: Disella chromolaena sp. nov. infesting Chromolaena odorata (Linnaeus) R. M. King & H. Rob. (Asteraceae); Abacarus oxalis sp. nov. from Oxalis corniculata L. (Oxalidaceae); Tetra radermachera sp. nov. infesting Radermachera sinica (Hance) Hemsl. (Bignoniaceae); Tegonotus microcarpae sp. nov. from Ficus macrocarpa L. f. ‘Golden Leaves’. (Moraceae); Aculops morindae Ghosh & Chakrabarati, 1989 rec. nov. from Paederia foetida L. (Rubiaceae); Shevtchenkella longitubercula Mo, Tan & Wang, 2017 rec. nov. from Dimocarpus longan Lour. (Sapindaceae). All mites are vagrants causing no apparent damage to their host plants. We provided mitochondrial COI sequences for Abacarus oxalis sp. nov. (GenBank accession numbers OQ571329 and OQ571330), Aculops morindae Ghosh & Chakrabarati, 1989 rec. nov. (OQ571325–OQ571328), and Tegonotus microcarpa sp. nov. (OQ571323 and OQ571324). A list of eriophyoid mites known from Guangxi University is given.

Dermatophagoides farinae (Acari: Pyroglyphidae) has been regarded as an important source of indoor allergens due to its prevalence and close proximity to humans. This study serves as an introductory probe into the population genetic structure of D. farinae, for which a few related studies of population genetic structure are available. In this study, the genetic structure of seven D. farinae populations in China was investigated based on the 372 bp mitochondrial cytochrome b (cytb) gene. A total of 29 haplotypes of the 68 cytb gene sequences were detected. The network diagram could be divided into Branch I (regions north of the Yangtze River: SJZ, CZ, FY and HN) and Branch II (regions south of the Yangtze River: AQ, WX and WH). Analysis of molecular variance (AMOVA) conducted according to the results of the network diagram revealed major genetic differentiation among groups, indicating that a significant genetic structure existed among groups. The results of population genetic structure could be largely attributed to geographical isolation. The existence of gene flow in a few populations may be influenced by grain trade activities. This study may facilitate a better understanding of the population genetic structure of D. farinae and could be utilized as the foundation for the development of efficient management strategies for D. farinae.

Russian species of the genus Paraseiulus Muma (Acari: Phytoseiidae) were reviewed based on the material collected in this study as well as previous literature reports. As a result, a new species, P. pseudoincognitus sp. nov., collected from leaves of Ulmus sp. (Ulmaceae) in Omsk Region, Russia, was described and illustrated from adults of both sexes. Moreover, supplementary descriptions and new illustrations of four species, P. incognitus Wainstein & Arutunjan, P. soleiger (Ribaga), P. triporus (Chant & Yoshida-Shaul) and P. xiningensis (Chen & Chu) were provided, based on the newly collected specimens to facilitate species delimitation. In addition, P. intermixtus Kolodochka was proposed as a new junior synonym of P. soleiger, and both P. trimediosetus (Xin, Liang & Ke) and P. inobservatus Kolodochka were synonymized with P. xiningensis. Identification key for the Russian species of the genus was provided.

The coconut mite Aceria guerreronis Keifer is considered one of the most important pests of the coconut tree (Cocos nucifera L.), causing fruit malformation due to the appearance of cracks on the surface of the perianth below the bracts. This damage compromises fruit growth, reducing the production of solid and liquid albumen. The continuous use of chemical pesticides increases pest control costs, as in addition to being a practice highly harmful to the environment, it can also cause selection of resistant populations, as well as eliminate beneficial species. Therefore, the objective was to evaluate the population dynamics of A. guerreronis and its natural enemies, through the quantification of the most frequent and abundant predator species in two commercial areas of coconut plantation of the cultivar PB-121 (cross between Malaysian Yellow Dwarf x West African Giant). The study was conducted in Area 1 (with pesticide application), and Area 2 (without pesticide application - control) monthly from August 2018 to July 2019. Leaflets were collected (basal, median and apical part) from leaf 14 and fruits (bunches 4, 5, 6 and 7–4 to 6 months after inflorescence fertilization). In both areas, 933.580 mites were collected, 426,245 in Area 1 and 507.335 in Area 2, with emphasis on A. guerreronis (931.706 specimens – estimated value). Eriophid mites represented almost 100% of the specimens sampled, with high population density in periods with less precipitation. Among the predators, specimens belonging to the Phytoseiidae family were predominant, highlighting the species Amblydromalus zannouii Famah Sourassou, Amblyseius aerialis (Muma) and Amblyseius tamatavensis Blommers, present both in leaflets and in fruits, with the exception of A. zannouii, which was found only in leaflets.

Cannibalism (intraspecific predation) and intraguild (interspecific) predation are widely observed phenomena in the animal kingdom, including amongst predatory mites of the Phytoseiidae family. While the larval stage of phytoseiids is a vulnerable and important life stage, it has received less attention than the adult stage. The larvae of phytoseiid species can be categorised into three types based on their feeding behaviour: non-feeding, facultative feeding, and obligatory feeding. This study aimed to investigate the occurrence of cannibalism and intraguild predation among the larval stages of three generalist predatory phytoseiids: Amblydromalus limonicus (Garman & McGregor), Amblyseius herbicolus (Chant), and Neoseiulus cucumeris (Oudemans). We hypothesised that the larval feeding type could influence the aggressiveness of the predators in intraspecific and interspecific encounters, with obligatory-feeding larvae being the most aggressive and non-feeding larvae being the least aggressive. To test this hypothesis, we conducted a no-choice experiment under laboratory conditions using larvae to observe the prevalence of predation among conspecifics and heterospecifics in these three predatory mite species. In addition to observing predation outcomes, we measured larval body size, cheliceral size, and cheliceral morphology to investigate these parameters' correlation with predation success. Our study revealed significant differences in the prevalence of cannibalism and intraguild predation among the three predatory species in agreement with our hypothesis: N. cucumeris larvae did not engage in predatory behaviours, while A. herbicolus displayed the highest predation success. Our findings suggest that cheliceral morphology may be a better indicator than body size of the aggressiveness of larval predation against conspecifics and heterospecifics. Our results provide valuable insights into the importance of larval behaviour in population dynamics and the development of effective pest management strategies. The study also highlights the need for further research on the larval stage of phytoseiids and emphasises the significance of considering larval behaviour when studying and managing these important predatory mites.