Molecular diet studies of water mites reveal prey biodiversity

Oligochaete DNA in Lebertia Although Chironomid larvae were already known to be part of the diet of Lebertia, these stud- ies show that some animals also had a large amount of oligochaete DNA. Some oligochaete OTUs had sequence identities >90% (examples are Chaetogaster diastrophus 98.5% in Fig 5A; Nais pseudobtusa, 98.8% in Fig 5B; and Amphichaeta raptisae 91% - 94% in data from seven L. davidcooki. and three L. quinquemaculosa). However, most sequences whose closest matches in GenBank were oligochaetes often had sequence identities below 90% compared to previ- ously barcoded oligochaetes (summarized in Table 4). These include Slavina sp., Chaetogaster spp., Stylaria fossularis, and others seen in Fig 5. The sequences of most Chaetogaster and Sty- laria, and all Amynthas, Piguetiella, and Slavina matched reference sequences no better than 80 to 90% (Table 4). DNA of mosquitoes and other taxa Mosquito (Culex pipiens) sequences, when present (e.g., Fig 4), usually had species level matches with >97% identity. The diet profile of the Lebertia quinquemaculosa specimen shown in Fig 4 indicates that although Chironominae made up most of the diet constituents of this animal, it had also fed on Culex spp., as represented by 10 sequences identified as Culex pipiens and 1 sequence identified as Culex conspirator. Altogether, 6 mite specimens (2 L. davidcooki and 4 L. quinquemaculosa) exhibited Culex spp sequences. Fig 3. Neighbor-joining tree of non-mite DNA OTUs in representative Lebertia davidcooki mite of PCR products

amplified with mLep/LCOI primers-Illumina adapter primers. Each branch is labeled with the “best hit” accession ID in GenBank, taxon name, and the percent identity of the OTU to its best hit. Mostly chironomids in a specimen of L. davidcooki. Color code: red, identities >96.5%; blue, identities 90% - 96.5%; black, identities 80% - 90%. All OTUs represent >4 sequences. https://doi.org/10.1371/journal.pone.0254598.g003 PLOS ONE Prey DNA diversity in water mites PLOS ONE | https://doi.org/10.1371/journal.pone.0254598 July 29, 2021 8 / 18