Location: Systematic Entomology Laboratory
2019 Annual Report
Objectives
ARS is interested in performing research to increase and enhance the understanding of the systematics of aphids, leafhoppers, plant bugs, thrips, and termites important to agriculture, ornamentals, and the environment. Our Project Plan has four main objectives:
Objective 1: Determine species boundaries; recognize, describe, and illustrate new and adventive species; develop identification keys; define relationships among the respective groups; and investigate host use and specificity of leafhoppers, true bugs, aphids, scale insects, and related groups that are pests of, or beneficial, to U.S. agriculture.
Objective 2: Develop accurate species concepts for aphids using a holistic approach based on morphological and molecular data.
Objective 3: Compile, organize, and post on web electronic databases and images of primary types of important aphids, leafhoppers, termites, thrips, and true bugs.
Objective 4: Provide expert identifications of specimens submitted by stakeholders worldwide and manage assigned portions of the U.S. National Insect Collection.
Approach
ARS will undertake the taxonomic research on agriculturally and economically important aphids, leafhoppers, plant bugs, termites, and thrips, using both morphological and molecular data to create species concepts and develop hypotheses about relationships. This information will be used to develop comprehensive revisions, including generic and species diagnoses and descriptions, illustrations of adults and diagnostic characters using light and electron microscopy, and dichotomous identification keys that will facilitate accurate identification. This information will be made available through publications, including hard-copy books, online pdf files, websites, and other media. Timely, accurate identifications of aphids, bugs, leafhoppers, termites, and thrips submitted by APHIS/PPQ, other state and Federal agencies, and a wide range of researchers will be provided. Large portions of the United States National Collection of Insects will be maintained and expanded.
Progress Report
Determining the species limits and synonymy of aphids that have wingless and winged forms is difficult. An analysis of 50,470 independent measurements and 20,600 ratios successfully grouped all synonymized species of a group of aphids (with wingless adult females) with their associated valid species and we concluded that most of the synonymies we tested are valid. This demonstrates that linear discriminant analyses can be used to test the validity of synonymies when DNA is unavailable and provides a new method to examine and use historic, slide-mounted specimens. This new method can be used to determine species limits and synonymy in all aphids. In collaboration with Texas A & M, a world-wide literature search of the predator/prey relationships in scales, aphids, and whiteflies resulted in ~3000 citations of which over 1600 citations (together with 4700 unique author) were imported into Bibliography of the Neuropterida database. For papers that contain useful predator/prey information, new electronic document records are created in the database, and the PDFs were archived for eventual display online, and for subsequent predator/prey data capture. Relative to other literature-review projects, this step is a distinguishing feature of our online project, as most of the data that we will eventually capture will be able to be linked to an actual PDF for review/verification. So far, we have archived about 650 new PDFs for the project. Tracing of additional PDFs and archiving for later data capture are ongoing workflows.
Completed diagnoses and descriptions for about 25% of Miridae 100 species; manuscript format and outline set up, lists of synonymy and literature completed. Lack of technical support has limited the amount of time available fully complete this milestone.
Due to a lack of technical support, capture of any additional Miridae type images was impossible. More than 850 images have been captured so far.
Two major contributions on the systematics of armored scale insects have been completed. One has been published in Molecular Phylogenetics and Evolution, the other is in press at Zootaxa. These works revise the hierarchical classification of the family, identify and discuss solutions to resolve problems with the generic classification, identify approximately 70 undescribed species, and characterize recurring diversification patterns that hold significance for understanding speciation in this and other scale insect families.
A project to estimate the phylogeny of all scale insect families has been initiated, using museum collections to generate phylogenomic data from ultraconserved elements. Approximately 150 DNA preparations have been generated, the majority of which come from ancient, dried museum specimens. This project uses cutting-edge phylogenomics techniques to reconstruct the phylogeny of scale insects.
An identification key to distinguish species of flat grass scale insects, including the Roseau cane scale, has been completed, submitted, and accepted for publication in ZooKeys. Accurate identification of Roseau cane scale is necessary following its recent introduction to the United States.
A book chapter describing the Roseau cane scale (identification, biology, distribution, natural enemies) has been submitted and accepted for publication in the Encyclopedia of Scale Insects (Hemiptera: Coccomorpha) of Agricultural Importance. A review of the known biological information regarding this significant pest of common reed is important following its recent introduction to the United States.
New distribution records and natural enemies of the False Meyer scale, Dynaspidiotus pseudomeyeri, have been published in Proceedings of the Entomological Society of Washington. This is the first report on natural enemies of a pest of ornamental trees.
Completed description of an unusual new species of the leafhopper Diestostemma. In internal review.
Completed manuscript on new distribution records for some rare Membracidae.
Completed manuscript on new species and generic transfers among species of Membracini.
Completed draft of tribe and generic descriptions of immatures of the tribes Aconophorini and Hoplophorionini.
Captured 774 habitus images and 1,032 head measurements of 258 new species of Darnini.
Made 234 urgent, 100 prompt, and 358 routine identifications of Sternorryncha as of 24 May 2019; 103 urgent, 99 prompt, and 161 routine identifications of Heteroptera as of 22 May 2019; and 220 urgent, 9 prompt, and 51 routine identifications of Auchenorrhyncha as of 22 May 2019.
Accomplishments
1. Protecting U.S. ornamental plants. Armored scale insects are major pests of crops and ornamentals. Armored scales are also among the most invasive insects in the world and are responsible for causing billions of dollars in agricultural damage annually. The United States instituted its first plant quarantine act (1905) following introduction of the San Jose scale, which devastated western agriculture at the turn of the century. Today, about 40% of armored scale species in the United States have been introduced; many of them are considered minor to major pests of crops and ornamentals. ARS scientists and collaborators studied the relationships of armored scale species to create a more informed classification system, providing a foundation for identifying pests of agricultural concern and understanding their biology and ecology. This work has an impact on the ability of scientists, biocontrol workers, extension agents, and regulatory agencies to monitor and control species introductions. Recent achievements resulted in a reclassification of subfamilies and tribes, and established goals for revising the classification of genera. This work elucidates the relationships of over 350 species of armored scale insects, roughly one-third of which are significant to agriculture.
2. Protecting Euphorb plants. A revision of plant bugs that attacks various species Euphorbiaceae, especially species of genus Euphorbia, was completed. These plant bugs were difficult to identify, some went by multiple names and others no names at all. Without accurate identifications it is difficult to find and gather information on pest biology, distribution, or what measures we can take to control them. Three species new to science were described. This was part or a larger effort to provide identification aids needed by researchers, extension officers, and regulatory agencies.
Review Publications
Miller, G.L., Metz, M., Wheeler Jr., A.G. 2018. What is “there?” Searching for the North American origin of the aphid Appendiseta robiniae. American Entomologist. 64(4):233-241.
Cranshaw, W., Halbert, S.E., Favret, C., Britt, K., Miller, G.L. 2018. Phorodon cannabis Passerini (Hemiptera: Aphididae), a newly recognized pest in North America found on industrial hemp. Insecta Mundi. 0662:1-12.
Schneider, S.A., Okusu, A., Normark, B.B. 2018. Molecular phylogenetics of Aspidiotini armored scale insects (Hemiptera: Diaspididae) reveals rampant paraphyly, curious species radiations, and multiple origins of association with Melissotarsus ants (Hymenoptera: Formicidae. Molecular Phylogenetics and Evolution. 129:291-303.
Schneider, S.A., Skvarla, M.J., Ochoa, R., Schmidt, S., Polaszek, A.P., Gates, M.W. 2019. Range extension of false Meyer scale, Dynaspidiotus pseudomeyeri (Kuwana) (Hemiptera: Diaspididae) in the United States, and newly recorded associations with a parasitoid and mite. Proceedings of the Entomological Society of Washington. 121(2):320-326.
Henry, T.J. 2018. Revision of the plant bug genus Semium (Heteroptera: Miridae: Phylinae: Semiini), with the description of three new species and a revised key. Proceedings of the Entomological Society of Washington. 120(3):508-532.
Henry, T.J., Brailovsky, H. 2018. A new species of the lace bug genus Acalypta (Hemiptera: Heteroptera: Tingidae) from Guatemala, and a spectacular new related genus and new species from Mexico. Proceedings of the Entomological Society of Washington. 123(3):533-542.
Riddick, E.W., Miller, G.L., Owen, C.L., Bauchan, G.R., Schmidt, J.M., Gariepy, T., Brown, R.L., Grodowitz, M.J. 2019. Discovery of Aphis ruborum (Hemiptera: Aphididae) and Aphelinus varipes (Hymenoptera: Aphelinidae) on cultivated strawberry in Mississippi, USA. Journal of Insect Science. 19(3):1-6. https://doi.org/10.1093/jisesa/iez045.
