Arachnids, including scorpions, harvestman, and mites, comprise an estimated 97,000 described species, but many new species remain to be discovered and described. Mites, in particular, due to their small size and wide distribution are poorly known and likely to harbor many new species. This research focuses on documenting the diversity and evolutionary relationships among velvet mites, chiggers, and water mites (Parasitengona). These particular mites are often the most abundant animals in a given habitat and can be useful indicators of ecosystem health in streams and forests. They have interesting life cycles, with parasitic larvae and predacious nymphs and adults. The larvae of most species are parasites of other arthropods and have been shown to affect host populations by shortening host life and reproductive capability. The larvae of one group - chiggers - are parasites of vertebrates and occasionally bite humans, causing irritation and public health concerns. The predatory nymphs and adults play important ecological roles as well, but they are also the most familiar, with some species being the largest and most colorful of all mites. This project will contribute to mite biology, but also has an extensive citizen science component that will engage the public and allow them to contribute to the knowledge of mites living in their area. Additionally, the project will work with K-12 educators to develop projects focused on the diversity of insects, scorpions, crabs, mites, and related animals (Arthropods) that will introduce students to the scientific method and improve observational skills and critical thinking.
The overall goal of this project is to integrate modern morphological and phylogenomic tools to develop a complete evolutionary picture of the largest radiation of mites, Parasitengona (velvet mites, water mites, and chiggers). The project will address this goal with two specific aims that will bridge the gaps in Parasitengona systematics and target key elements meant to reach broader audiences. The first aim is to create a robust phylogenetic hypothesis for Parasitengona using an anchored hybrid enrichment protocol to sequence approximately 1000 loci across 600 taxa. The resulting phylogenetic hypothesis will solidify the currently unstable classification and present a tool for testing many evolutionary questions, including two core events that have had the greatest impact on Parasitengona diversification: 1) the shift from predator to protelean parasite and subsequent host shifts; and 2) the invasion of freshwater. The second aim is to reconcile previous research on parasitengone morphology with modern approaches. An internal morphological survey will use modern non-destructive 3D imaging techniques such as confocal scanning microscopy to yield digital interactive models. An extensive external morphological survey using low-temperature scanning electron microscopy to gain unprecedented amounts of morphological information. Lastly, the project will integrate these new findings with legacy data into a matrix-format that will assist with understanding the evolution of the group and will be the first step to developing an online anatomy ontology for all mites. Overall, the project will produce an unparalleled amount of data for mites and develop a foundation for a multitude future research directions.
