Hydrodroma angelieri (Acari, Hydrachnidia: Hydrodromidae) a new water mite species from Corsica based on morphological and DNA barcode evidence

In the present study we used morphological data and DNA barcodes to describe a new species, Hydrodroma angelieri sp. nov. from Corsica, France. A high genetic distance of 17.3±0.017% K2P from its molecularly most closely related European congener, H. despiciens (Müller, 1776), supports H. angelieri sp. nov. as a distinct species. Morphologically the new species can be identified on the basis of relatively small leg claws, the presence of only one swimming seta on II-L-5 and 4-6 swimming setae on the anterior surface of IV-L-5. An updated key for the European species of Hydrodroma is provided.

A list of water mite types transferred from the Museum of the Natural History in Podgorica and deposited in other museums

A list of the water mites (Acari, Hydrachnidia) types originally stated to be deposited in the Museum of Natural History in Montenegro, Podgorica, Montenegro and later on transferred to Museum of Natural History in Basel (Switzerland) and Naturalis Biodiversity Center in Leiden (the Netherlands) is given.

New records of water mites from the Balkans revealed by DNA barcoding (Acari, Hydrachnidia)

New records of water mites from Serbia, North Macedonia and Greece revealed by DNA barcoding are presented. DNA barcodes were recovered from 63 water mite specimens morphologically assigned to 32 species. One species Lebertia algeriensis Lundblad, 1942, is reported for the first time for the Balkans; four species, i.e. Lebertia fimbriata Thor, 1899, L. rivulorum K. Viets, 1933, Atractides stankovici Pešić & Gerecke, 2010, and Wettina lacustris Pešić & Smit, 2018 are new for North Macedonia; Monatractides madritensis (K. Viets, 1930) and Mideopsis roztoczensis Biesiadka & Kowalik, 1979 are new for Serbia; and Hygrobates mediterraneus Pešić, 2020 is new for Greece. Comparing sequences of our study with the available COI sequences we recognized five possible cases of cryptic diversity involving species clusters with more than 5% divergence indicating that these species need further study.

Description of a new water mite species of the genus Lebertia Neuman, 1880 (Acari, Hydrachnidia: Lebertiidae) from Kazakhstan

A new water mite species of the subgenus Septlebertia Imamura, 1954, Lebertia boldyrbekensis sp. n. is described from running waters in the Republic of Kazakhstan. An identification key for all species of the subgenus Septlebertia is presented.

Experiments on invertebrate predation on cladocerans and its relationships with lake data

Until recently, knowledge of the impact of invertebrate predators on cladocerans in the Brazilian Lake Monte Alegre was limited to a few species. In order to assess the effects of predation on other cladoceran species, experiments were carried out with different pair-wise combinations of prey species. The experiments tested predation by fourth instar larvae of the dipteran Chaoborus brasiliensis Theobald on neonates and adults of the cladocerans Daphnia gessneri Herbst, Diaphanosoma birgei Kořínek, and Ceriodaphnia richardi Sars, and predation by the water mite Krendowskia sp. on neonates and adults of C. richardi and D. gessneri. In replicated treatments, the prey was offered alone or in combination with neonates and adults of two species and kept in bottles on a plankton wheel under controlled temperature, photoperiod, and light conditions. Chaoborus larvae preyed on neonates of D. birgei and D. gessneri and on adults of the former species. They preyed preferentially on neonates and adults of D. birgei over neonates and adults of C. richardi. The mite Krendowskia sp. preyed on only one species: neonates and adults of D. gessneri. Data on the distribution and strategies of prey in the lake are discussed in light of the experimental results, in an attempt to establish a link between laboratory data and field conditions.

Molecular diet studies of water mites reveal prey biodiversity

Water mites are diverse aquatic invertebrates that provide potentially important ecosystem and economic services as bioindicators and mosquito biocontrol; however, little is known about water mite digestive physiology, including their diet in nature. Water mites, much like their spider relatives, liquefy their prey upon consumption. This results in the absence of morphologically identifiable prey in water mite mid-gut. Previous studies have reported associations in the field of water mites with presumed prey and laboratory observations of water mites feeding on specific organisms offered for ingestion; however, the present work aims to determine what water mites have ingested in nature based on molecular studies of gut contents from freshly collected organisms from the field. To elucidate water mite prey, we used next-generation sequencing to detect diverse cytochrome oxidase I DNA barcode sequences of putative prey in the guts of 54 specimens comprising two species of Lebertia and a few specimens of Arrenurus (2) and Limnesia (1). To our knowledge this is the first molecular study of the diets of water mites as they feed in nature. While the presence of chironomid DNA confirmed previous observations of midge larvae as part of the diets of Lebertia, we also found the DNA of diverse organisms in all four species of water mites, including the DNA of mosquitoes in 6 specimens of Lebertia and a large number of previously unknown prey, especially from oligochaete worms. These studies thereby reveal a greater diversity of prey and a potentially broader significance than previously appreciated for water mites in aquatic food webs. Molecular studies like this can detect water mite predators of mosquito larvae and add knowledge of water mite predatory contributions to freshwater food webs.

Two new water mite species of the genus Hydrodroma Koch, 1837 from New Caledonia (Acari, Hydrachnidia: Hydrodromidae)

Two new water mite species of the genus Hydrodroma Koch (Acari: Hydrachnidia, Hydrodromidae) are reported from New Caledonia, i.e. Hydrodroma novacaledonica sp. nov. and H. pacifica sp. nov. An updated key for the Australasian species of Hydrodroma is provided.

Description of a new water mite species of the genus Kongsbergia Thor, 1899 (Acari, Hydrachnidia: Aturidae) from Kazakhstan

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