Uniting modern tools of phylogenomics and morphology to address the evolution of acarology's most charismatic members: velvet mites, chiggers, and water mites

Mites are extremely diverse arachnids living around and on us, yet they are often overlooked because of their small size. This research focuses on a group of mites (Parasitengona) that includes velvet mites, chiggers, and water mites. 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 concern. The predatory nymphs and adults play important ecological roles too, but they are also familiar to many of us, with some species being the largest and most colorful of all mites. In fact, given the abundance of photographs regularly posted online, it is obvious these charismatic mites capture public attention. This project will greatly contribute to mite biology, but it also aims to bridge the gap between science and the public. This will be accomplished through a large citizen science effort that will engage the public in active research 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 arthropod-focused projects that will introduce students to the scientific method and improve observational skills and critical thinking. More importantly, these projects will show students the important roles that tiny organisms play in their ecosystems and that if they look closely, they can find a diverse, virtually unknown world living right in their backyard.

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). We 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.