Project : USDA ARS

ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Systematic Entomology Laboratory » Research » Research Project #438801

Research Project: Systematics of Acari and Hemiptera: Plant Pests, Predators, and Disease Vectors

Location: Systematic Entomology Laboratory

2022 Annual Report

Objectives
New Objective 1: Conduct integrative systematic research of molecular (including Ag100Pest data) and morphological data to: determine species boundaries; recognize, describe, and illustrate new and invasive species; develop identification keys; hypothesize phylogenetic relationships among the respective groups for the purpose of stabilizing classification and providing predictive relationships of species; and investigate host associations and specificity of Acari (mites), Aphidomorpha (aphids), Membracoidea (leafhoppers and treehoppers), Aleyrodomorpha(whiteflies), Coccomorpha (scale insects), and Heteroptera (true bugs) that are pests of or beneficial to U.S. agriculture. [NP304, C1 PS1A; C2 PS2B; C3 PS3A and 3B] New Objective 2: Develop web-searchable electronic databases, tools, and images of mites, aphids, whiteflies, scale insects (Sternorrhyncha), leafhoppers (Auchenorrhyncha), and true bugs (Heteroptera) in the U.S. National Insect and Mite Collection and obtained through field exploration. This includes developing web-based resources to improve technology transfer of research products and disseminating this information to a broad group of stakeholders (e.g., quarantine, conservation, and biological control personnel). The proposed products will include searchable databases and expert systems of certain mites and hemipteran families. [NP304, C1 PS1A; C2 PS2B; C3 PS3A and 3B] New Objective 3: Provide authoritative identifications of specimens submitted by stakeholders worldwide and manage and curate assigned portions of the U.S. National Insect and Mite Collection, including all taxa in the hemipteran suborders Heteroptera, Auchenorrhyncha, Sternorrhyncha, and Coleorrhyncha, which involve more than one and a half million specimens housed in more than 3,000 insect drawers and mounted on hundreds of thousands of microscope slides, and the Acari with more than 360,000 microscope slide containing over a million specimens. [NP304, C1 PS1A; C2 PS2B; C3 PS3A and 3B]

Approach
Morphological characters will be identified through the examination of specimens using dissecting, DIC, Phase Contrast, CLSM, TT-SEM and Cryo SEM. Use of Cryo-SEM in mite taxonomy is revealing remarkable new character systems that were previously unknown and allowing researchers to re-evaluate poorly understood morphological characters that are difficult, if not impossible, to evaluate based on traditional slide-mounted preparations. This technique not only greatly expands the array of morphological characters available, offering them in greater detail, but it also provides valuable behavioral characters, especially with respect to understanding mite feeding behavior. Cryo-SEM will be used to confirm the intricate details of certain morphological characters visible with light microscopy, especially those of the tarsi and empodia. The novel characters available with Cryo-SEM (e.g., tegument texture and tarsal morphology) will be investigated and assessed using a minimum of 5 species from each genus, or more as time and resources permit. The validity of key characters for separating species and genera will be investigated across the family. TT-SEM and CLSM technologies will be used to further the morphological studies. Although the research will focus primarily on morphological and ecological characters of 4 tetranychid genera and 4 eriophyid genera, these data sets will be augmented with molecular data (COI, 18S, 28S, EF-1') as an exploratory avenue for systematic research in these taxa. We will collaborate with Dr. Ashley Dowling and his team at the University of Arkansas who have expertise in molecular characterization of mites. Character information will include the external and internal morphology of mounted flat mites, adults and immatures, combined with the molecular data and analyzed using TNT and MrBayes. Live specimens used for Cryo-SEM studies will be solicited from colleagues and/or brought into the laboratory from domestic and/or foreign fieldwork following standard quarantine regulations and evaluated for morphological characters. In addition, some slide-mounted specimens will be borrowed from or examined at various institutions worldwide, especially the type specimens located in Canada, Brazil and Australia. More than half of the type specimens located at the National Mite Collection (Beltsville, MD) have been studied under DIC and Phase Contrast microscopy. Additional specimens will be collected from regions that are poorly represented in accessible collections, including Australia, South America, India and China. Methods of preparation and preservation will follow those previously described for slide mounting and Cryo-SEM.

Progress Report
Several genera of mites in the families Eriophyidae, Phytoptidae and Diptilomiopidae (Eriophyoidea); Tenuipalpidae and Tetranychidae (Tetranychoidea) were acquired and mounted for studies under the DIC microscope, tabletop SEM and the cryo-scanning electrom microscope. Several genera in the family Eriophyidae were mounted and studied. Several genera in the order Acariformes (Parasitengona) were reviewed and safe for further molecular studies. In collaboration with the Smithsonian, University of Florida, and the Floral Nursery & Plants Research Unit at the National Arboretum a revision of literature search of plant feeding mites associated with diseases (fungi and viruses) has been compiled. Made 521 urgent identifications, 435 digital imagery identifications, 2 molecular and 84 morphological identifications.

Accomplishments
1. Eriophyoidea and Tetranychoidea. Systematic studies of plant feeding mites in the super families Tetranychoidea and Eriophyoidea were accomplished. Taxonomy studies in the Acariformes, Parasitengona were accomplished. Several studies on species in the family Eriophyidae associated with viruses as well analysis of the genus-virus associations and the impact on several fruit trees and ornamentals were done in collaboration with the National Arboretum. ARS Researchers at Beltsville, scientists from Animal Plant Health Inspection Service (APHIS), University of Florida, State Departments of Agriculture of California, Hawaii and Florida. Brazil, Mexico, Peru and Argentina. Several observations and measurements of mites collected in the United States were done using differential contrast light microscopy, confocal microscopy, tabletop SEM and low temperature scanning electron microscopy, which allowed the researchers to define characteristic structures and patterns for the correct identification of the mites. We received a donation of a one of the best North American soil mite collections. The Oribatida collection has been reviewed and prepared by a New York scientist for inclusion in the National Insect and Mite Collection of the Smithsonian.

U.S. DEPARTMENT OF AGRICULTURE

Systematic Entomology Laboratory: Beltsville, MD