Can DNA barcoding reveal predatory mites for biological control against redlegged earth mite, Halotydeus destructor?

Abstract

Abstract Predatory mites have potential to provide biocontrol against invertebrate pasture and crop pests. However, more information is needed on which species are effective as predators of agricultural pest species in a field setting. This study uses DNA barcodes to investigate species diversity of predatory mites associated with the redlegged earth mite (RLEM), Halotydeus destructor (Tucker) (Trombidiformes; Penthaleidae), a major Australian pasture and crop pest. We also use DNA barcodes to investigate whether these predatory mites ingest RLEM or other invertebrates. Predatory mites from the family Bdellidae were the dominant group across collection sites in southern Australia. DNA barcodes were linked to taxonomic identifications and showed all Bdellidae were from a single genus, Odontoscirus. Barcode diversity was high, particularly at sites from Victoria, Australia. Most species barcodes were not found in published DNA sequence databases. There was little evidence predatory mites frequently fed on RLEM; only three individuals from the Bdellidae species Odontoscirus (Bdelloides) lapidaria (Kramer) (< 2% of Bdellidae predatory mites surveyed) showe evidence of ingesting RLEM, and Collembola formed the main dietary component detected. This study highlights predatory mite biodiversity as revealed by DNA barcoding and the potential use of barcodes in assessing dietary preferences of different mite species under field conditions.