The production of apples (Malus domestica: Rosaceae) in Brazil is concentrated in three states in the southern region of the country. This crop is of great economic importance for the region, and is usually susceptible to infestations of mite populations. However, recent surveys of mite species associated to apples are scarce. The aim of the present study was to fill this void by analyzing species abundance and composition on three apple cultivars in the southern region of Brazil. The survey was carried out in the states of Rio Grande do Sul (RS), Santa Catarina (SC), and Paraná (PR). A total of 94 apple orchards were evaluated (43 Gala, 40 Fuji and 11 Eva), in 19 municipalities. Twenty plants were sampled from each orchard in March 2019, with four leaves collected from each plant, thus totaling 80 leaves/orchard. Mites were screened and identified in the Laboratório de Acarologia of Universidade do Vale do Taquari - UNIVATES. Data were analyzed using the R software with mixed generalized linear models, non-metric multidimensional scaling, and PERMANOVA. A total of 4,909 mite specimens were identified, belonging to eight species and six genera, of which 1,833 were classified as phytophagous, 1,758 as predators, and 1,318 as generalists. The most abundant phytophagous species was Aculus schlechtendali (33.55%), followed by the predator Neoseiulus californicus (33.14%) and by the generalist Tarsonemus (Tarsonemus) sp. (23.99%). Abundance was similar between Eva and Fuji cultivars. However, these cultivars differed in composition, as did Eva and Gala. The mean number of mites found in Santa Catarina and Rio Grande do Sul was similar, although Paraná had a higher number. Species composition also differed among the three states evaluated. Considering the importance of the apple production in the southern region of Brazil, studies on species composition and abundance are important, aiming to monitor potential damage-causing organisms to the crop and associated predators.

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Many studies have reported that the interaction between water mite larvae and their Odonata hosts affects mating success, flight, and longevity. Males and females of Odonata species collected in the steppes and coastal plains (Pampa Biome) of Rio Grande do Sul were analyzed. Mites were removed when present and the prevalence and intensity of parasites was calculated. The aim of this study was to search and report new Odonata hosts species that are parasitized by water mite larvae and also to evaluate the prevalence and intensity rates; the differences in mite occurrence and frequency between males and females, and between thorax and abdomen of the dragonflies and damselflies in the southern Pampa biome located in Rio Grande do Sul. A total of 162 larval mites were found associated to two Odonata families: Coenagrionidae (Acanthagrion lancea Selys, 1876, Ischnura capreolus Hagen, 1861 and Ischnura fluviatilis Selys, 1876) and Libelullidae (Micrathyria ocellata Martin, 1897 and Perithemis mooma Kirby, 1889). All mites were identified as Arrenurus (Arrenurus) sp. (Arrenuridae) and showed high numbers when attached to I. capreolus (55.5%), I. fluviatilis (33.3%), followed by low numbers on M. ocellata (6.1%), A. lancea (3.7%), and P. mooma (1.2%). Mites were found on males and females of I. capreolus and I. fluviatilis, females of A. lancea and P. mooma and in M. ocellata only in males. As the parasitized Odonata species are generalist and abundant in all water body types, traits associated with mating and oviposition or larval behavior are believed to explain the frequency of parasitism in these species.