Location: Systematic Entomology Laboratory2019 Annual Report
Objective 1: Develop accurate species concepts within the Tenuipalpidae (flat mites) using a holistic approach based on morphological and ecological data. Objective 2: Develop accurate species concepts within the Tarsonemidae (white mites) through discovery of new characters for species separation and subsequent systematic relationships. Objective 3: Coordinate the process of incoming and outgoing arthropod specimens and identifications, and maintain SELIS (Systematic Entomology Laboratory Identification Service), the on-line identification database on agriculturally important arthropods, for use in quarantine, conservation, pest management, and other ARS research programs.
Morphological characters will be identified through the examination of specimens (~2500 slides) located at the National Mite Collection and specimens collected from the Americas, Australia and China. Observation of the specimens will use dissecting, Differential Interference Contrast (DIC), Phase Contrast, Confocal Laser Scanning Microscopy (CLSM), Variable Pressure Scanning Electron Microscopy (VP-SEM), and Low Temperature Scanning Electron Microscopy (LT-SEM). Recognized morphological characters of several mite genera in the families Tarsonemidae and Tenuipalpidae will be identified, quantified, and used to develop hypotheses of phylogenetic relationships among higher level taxa. The characters will be evaluated using modern phylogenetic programs. The resulting phylogenies will be used to develop natural, robust classifications of higher level taxa among and within these four families.
Subtantial research progress was made in the fallowing areas: Under the Objective 1, more than 200 specimens from Brazil, Mexico, Peru and U.S., of Brevipalpus have had DNA extracted. DNA sequences have been compared with other Brevipalpus in four different groups (B. phoenicis, B. californicus, B. cuneatus and B. obovatus). This initial work has resulted in separating more than 12 species for the complex of species in the Brevipalpus californicus Group. This will help the confusion in this important economic plant feeding mite group and points to the correct species vector of nuclear leprosis virus. Futhermore, with DNA and LT-SEMtechniques, key characters have been identified to separate the true phylogenetic relationship of the species in the genus. Mites in the genera Tenuipalpus, Cenopalpus, Pentamerismus, Raoiella and Brevipalpus (ACARI: Tenuipalpidae) intercepted at ports-of-entry or mites important in plant protection programs were evaluated and studied. Scanning electron micrograph images and keys for some important tenuipalpid mites (including species in the genus Brevipalpus, Tenuipalpus, Cenopalpus and Raoiella) were accomplished. Under Objective 2, mites in the genera Tarsonemus Excelsotarsonemus, Daidalotarsonemus, Metatarsonemus, Fungitarsonemus and Ceratotarsonemus (ACARI: Tarsonemidae) were collected from the USA, Costa Rica, Brazil, Peru, China or/and intercepted at ports-of-entry. Scanning electron micrograph images and keys for some important tarsonemid mites (including species in the genus Fungitarsonemus, Excelsotarsonemus, Daidalotarsonemus, Metatarsonemus and Ceratotarsonemus were accomplished; under Objective 3, seveal prostigmatid mites, in special on the families Cheyletidae, Phytoseiidae, Laelapidae, Tuckerellidae, Eriophyidae and Tetranychidae were studied. Important findings under the LT SEM on several spider mites (Oligonychus, Mononychellus, Bryobia and Bryobiella) were accomplished; and total of 159 urgent identifications for a total of 532 specimens of ACARI as of 1 June 2019; 164 routine/promts identifications with 670 specimens of ACARI as of 1 June 2019 were made.
1. Understanding the role of mites and viruses. Systematic studies of plant feeding mites in the families Varroidae, Macronyssidae, Trombiculidae, Tarsonemidae, Tenuipalpidae, Tetranychidae and Eriophyiidae have been accomplished. Continuous studies on species in the families Tenuipalpidae and Eriophyidae associated with viruses are helping to understand the genus-virus associations and impact on several fruit trees and ornamentals. ARS Researchers at Beltsville, Maryland, in collaboration with researchers from the USA (Animal Plant Health Inspection Service (APHIS), University of Maryland, Ohio State University, University of Arkansas, State Departments of Agriculture of California and Florida), Brazil, and Mexico, are working in the identification of economic invasive pest. Extensive observations and measurements of mites collected worldwide were studied using differential contrast light microscopy, confocal microscopy, table top SEM and low temperature scanning electron microscopy, which allowed the researchers to define characteristic structures and patterns for the correct identification of the mites. This information has been disseminated by several publications and an on-line web pages which has over thousands visits/year from more than 180 countries. This research will be used by scientists, agriculture extensionists and border inspection agents to safeguard our country from invasive, destructive arthropods and diseases.
2. A reassessment of varroa mite feeding. Systematic studies of plant feeding mites belonging to several families, Tetranychidae, Tenuipalpidae, Eriophyidae, and Tarsonemidae have been accomplished. Systematic studies of mites affecting animals and insects importance in Agriculture have been accomplished. Studies of mites, affecting bees have been key to a major break in the understanding of morphology and feeding behavior. We collaborated with the University of Maryland, Department of Entomology, on a major publication of varroa mite feeding behavior. Varroa mites contrary to what the literature indicates feed on adult bees as well the larva, furthermore varroa mites are feeding on the fat rather than hemolymph. The understanding of varroa feeding on fat tissues will help future studies on management and control of this pest. The use of several techniques, including Low Temperature Scanning Electron Microscopy and confocal microscopy were key in the publication of this article.
Castro, E.B., Ochoa, R., Feres, R. 2018. A new species of Terminalichus (Trombidiformes: Tenuipalpidae) from Thailand, with a key to the known species. Systematic and Applied Acarology. 22(9):1431-1443.
Ramsey, S., Ochoa, R., Bauchan, G.R., Gulbronson, C., Mowery, J., Cohen, A., Lim, D., Joklik, J., Cierco, J., Ellis, J., Hathorne, D.J., Vanengelsdorp, D. 2019. Varroa destructor (Varroidae) feed on honey bee fat body tissue not hemolymph. Proceedings of the National Academy of Sciences. 116(5):1792-1801.
Beard, J.J., Ochoa, R., Bauchan, G.R., Dowling, A.G. 2018. Raoiella (Trombidiformes: Tenuipalpidae) of the world. Zootaxa. 4501(1):1-302.
Bassini-Silva, R., Jacinavicius, F.C., Maturano, R., Munoz-Leal, S., Ochoa, R., Bauchan, G.R., Labruna, M., Barros-Battesti, D.M. 2018. Blankaartia sinnamaryi (Floch & Fauran, 1956) (Trombidiformes: Trombiculidae) parasitizing birds in southeastern Brazil, with notes on Rickettsia detection. Revista Brasileira de Parasitologia Veterinaria. 27:354-362.
Bolton, S.J., Bauchan, G.R., Chetverikov, P.E., Ochoa, R., Klompen, H. 2018. A rudimentary sheath for the smallest of ‘biting’ chelicerae; A precursor to the stylet sheath of Eriophyoidea (Acariformes). International Journal of Acarology. 44(8):374-381.
Yi, T., Ochoa, R. 2019. Revision of Bryobiella Tuttle & Baker (Acari, Tetranychidae), with ontogenetic development and redescription of B. desertorum. Zootaxa. 4540(1):93-131.
Otero-Colina, G., Ochoa, R., Amrine, J., Hammond, J., Jordan, R.L., Bauchan, G.R. 2019. Eriophyoid mites found on roses in the United States. Journal of Environmental Horticulture. 36(4):146-153.
Bauchan, G.R., Otero-Colina, G., Hammond, J., Jordan, R.L., Ochoa, R. 2019. Rose rosette disease: It all started with a small mite. Acta Horticulturae. 1232(33):227-232. https://doi.org/10.17660/ActaHortic.2019.1232.33.
Castro, E.B., Ochoa, R., Bauchan, G.R., Feres, R. 2019. Two new species of Tenuipalpus sensu stricto (Acari; Tenuipalpidae) from Brazil, with a discussion on the ontogeny of leg setae. Zootaxa. 4540(1):178-210.