DNA barcodes expose unexpected diversity in Canadian mites

Area of Science:

• * Arthropodology and acarology, focusing on the biodiversity of mites (Arachnida: Acariformes, Parasitiformes).
• * Molecular ecology and DNA barcoding applications in biodiversity assessment.

Background:

• * Mites are the most abundant and species-rich arthropods in soil and diverse in other habitats.
• * Accurate assessment of mite diversity is challenging due to their small size and cryptic morphology.
• * Previous species richness estimates for mites vary widely, from 0.4 to 114 million species globally.

Purpose of the Study:

• * To investigate mite diversity across Canada using DNA barcoding and the Barcode Index Number (BIN) system.
• * To assess mite species richness in various habitats, primarily soil and litter.
• * To compare DNA-barcoding-based diversity estimates with previously recorded species numbers.

Main Methods:

• * DNA barcoding was performed on 73,394 mite specimens collected from over 1,800 sites across Canada.
• * Specimens were sourced from diverse habitats including soil, litter, freshwater, plants, and animal hosts.
• * The Barcode Index Number (BIN) system was used to cluster unique DNA barcodes and estimate diversity.

Main Results:

• * A total of 7,077 BINs were identified, representing all four major mite orders and 60% of known families.
• * The number of BINs (7,077) is 2.4 times higher than the 2,999 mite species previously recorded in Canada.
• * Projections indicate over 30,000 mite species in Canada, comparable to the diversity of Diptera (true flies).

Conclusions:

• * Canadian mite fauna is significantly more diverse than previously estimated, with over 30,000 species likely present.
• * Mite diversity is spatially structured into distinct assemblages, suggesting dispersal limitation and environmental influences.
• * Further research in diverse habitats and geographic regions is needed to fully understand global mite diversity.