The parthenogenetic mite Labidostomma luteum (Acarina Actinotrichida: Labidostommidae) in Finland

摘要

Labidostommidae represents the only well sclerotized group of actinedid (prostigmatid) mites in Finland. This study confirms the presence of Labidostomma luteum Kramer, 1879 in southernmost Finland. This species has previously been reported in the nests of forest-dwelling singing birds without locality data, though the records were most probably based on misidentifications. Although it has not been found in arboreal nests, its known habitats in Finland indicate a wide ecological range within the SW archipelago. It has a patchy distribution and has been found in less than 8% of Berlese samples from suitable habitats in the SW archipelago. Only parthenogenetic populations of this species have been reported from Central Europe, with a limited area of bisexual populations in southern France. The 44 Finnish parthenogenetic populations have been mainly found in the SW archipelago on 29 islands. We report two mainland records from Sauvo in SW Finland with a widely separated record from Ylaemaa, SE-Finland. This review of the total range of the species is based on a parallel revisional study of Labidostommidae. All stages of the parthenogenetic L. luteum are redescribed and SEM micrographs are presented for the most important diagnostic characters. L. luteum repetitor Grandjean, 1942 is raised to specific rank, and L. jacquemarti Coineau, 1964 is considered its junior synonym.