Molecular diet studies of water mites reveal prey biodiversity

Laboratory feeding experiments with L. quinquemaculosa (Fig 2A) demonstrate that L. quinquemaculosa will attack and ingest dipteran aquatic larvae, such as chironomid (midge fly, Fig 2A) and mosquito larvae (Fig 2B), consistent with the only prey listed for Lebertioidea mites in an authoritative review [8]. When offered larvae of Drosophila, an animal that they would never expect to encounter in the aquatic environment, they also attacked it (Fig 2C). To determine what water mites eat in nature, a preferred method would be to observe them directly attacking organisms in their natural environment (difficult given their microscopic size) or, as we have done, examining what animals freshly collected from the environment have ingested. DNA extracted from six freshly caught Lebertia with primers mLep/LCO1490, designed to amplify non-mite DNA, showed that field-collected specimens contained diverse non-mite sequences (S2 Table). For example, non-mite DNA from Lebertia 6-BHL022317 had 100% Fig 1. Two species of Lebertia water mites found in Blue Heron Lagoon. A, L. quinquemaculosa dorsal and B, ventral. C, L. davidcooki dorsal and D, ventral. Calibration bars = 500 μm. https://doi.org/10.1371/journal.pone.0254598.g001 Table 2. Prey DNA in mites after laboratory feeding. Predator Prey GenBank match�: Lebertia quinquemaculosa Culex pipiens C. pipiens Q100%; ID99% L. quinquemaculosa C. pipiens C. pipiens Q100%; ID99% L. quinquemaculosa C. pipiens C. pipiens Q98%; ID99% Lebertia davidcooki Chironomid Chironomidae sp. Q100%; ID97%

Lebertia davidcooki Chironomid Cricotopus sp.Q99%; ID97% �GenBank Query coverage (Q) and percent identity (ID) of mLep/LCO1490 PCR products https://doi.org/10.1371/journal.pone.0254598.t002 PLOS ONE Prey DNA diversity in water mites PLOS ONE | https://doi.org/10.1371/journal.pone.0254598 July 29, 2021 6 / 18