Location: Systematic Entomology Laboratory
2019 Annual Report
Objectives
ARS is interested in performing research to increase and enhance understanding of the systematics of flies (Diptera) important to agriculture and the environment, especially fruit flies, leaf-mining flies, tachinid flies. We will develop new identification tools (descriptions, diagnoses, molecular markers, illustrations, keys and computer identification systems), determine the correct names of species and higher taxa, and elucidate the relationships (phylogeny) and classification of select groups of these flies, which include invasive crop pests, parasitoids of plant pests, and potential biological control agents for weeds. The objectives of our project are: 1) Investigate the taxonomy and natural history of fruit flies; analyze species concepts, develop diagnoses, descriptions, illustrations and identification tools, biosystematic databases, determine host plants, and analyze phylogenetic relationships; 2) Conduct molecular systematic and ecological analysis of pest leaf-mining, galling, and fruit flies, and their parasitoids, including sequencing of DNA of previously unstudied species, development of diagnostic tools, discovery of possible cryptic species and host races, and analysis of phylogenetic relationships; 3) Investigate taxonomy of tachinid flies and other higher flies; analyze species concepts, develop diagnoses, descriptions, illustrations and identification keys, and analyze phylogenetic relationships; and 4) Provide scientific identifications of plant-feeding and other agriculturally important flies.
Approach
ARS will undertake research to generate morphological and molecular characters (DNA sequences) that will be used to test species concepts and hypotheses of relationship among agriculturally important flies and parasitoid wasps that attack them. These data also will be used to develop new diagnostic tools (descriptions, illustrations, keys) to permit more rapid and accurate identification of these flies and wasps. Databases containing scientific names, distributions, taxonomic literature, and host plant and specimen data pertaining to fruit flies will be expanded and disseminated to the user community. These and other taxonomic tools will be made accessible to the public via publications, the internet, and other electronic media. Timely and accurate identifications of flies will be provided, including those intercepted at ports-of-entry by APHIS-PPQ or submitted by a wide range of scientists and regulatory agencies, and portions of the National Collection in the National Museum of Natural History, a vital tool for research and identification, will be maintained and expanded.
Progress Report
Taxonomy and natural history of fruit flies. Accomplishments on the taxonomy of the largest and most economically important group of fruit flies in the American tropics (Anastrepha) included the following: publication of research justifying the inclusion of a group of derived species (previously known as Toxotrypana), including the papaya fruit fly; further development of an electronic identification tool for the more than 350 species of this group; preparation for publication of a large data set of DNA sequences (including more than 1900 COI sequences from 260 species); sequencing by anchored hybrid enrichment of hundreds of loci of 90 species of Anastrepha (to be analyzed for species diagnosis and phylogenetic relationships); and collection of thousands of additional samples for DNA analysis. A revision of the taxonomy of a small group of fruit flies feeding on flowers in the sunflower family was published. Data from additional publications were added to names, host plant, and distribution databases for fruit flies, and the Animal and Plant Health Inspection Service (APHIS)-Center for Plant Health Science and Technology (CPHST) web site serving this information was enhanced. This information is critical to APHIS-Plant Health Quarantine (PPQ) and other regulatory agencies to prevent the spread of pest species into the U.S. Molecular systematic and ecological analysis of plant-feeding flies and their parasitoids. Taxon-specific primers were designed for mitochondrial DNA barcode genes in true fruit flies (Blepharoneura) that breed in relatives of pumpkins, cucumbers and squash, and for Bellopius braconid and other wasp parasitoids attacking the flies. Barcode data were collected with a MinION next-generation DNA sequencer, a device using novel technologies to allow the collection of hundreds of long-read sequence data. Primer design included a number of index sequences to allow for individual identification following extensive multiplexing during polymerase chain reaction (PCR). This technology results in a greater amount of data more quickly and more cheaply than is possible with traditional Sanger sequencing. Novel protocols were designed and tested to allow this equipment to be used in remote or poorly equipped locations. These newly developed methods provide a new and rapid approach to mass identifications of pests and other insects. They will be of great interest to a variety of systematists, ecologists, and evolutionary biologists as well as to APHIS-PPQ and other regulatory agencies working to prevent the spread of pest species into the U.S. Taxonomy of tachinid flies and other higher flies. The scientist responsible for this objective retired and the position is vacant.
Scientific identification of agriculturally important flies. In the period from October 1, 2018 to May 22, 2019, 220 submittals (805 specimens) were identified, including 155 "urgent" submittals for USDA-APHIS-PPQ of specimens intercepted on perishable commodities at ports-of-entry.
Accomplishments
1. Protecting American agriculture from pest fruit flies. True fruit flies include some of the most important pests of commercial fruits. Of the 5000+ currently known species, more than 100 are agricultural pests, attacking commercial and subsistence crops including citrus, mango, peach, apple, and many others. Many species are invasive and threaten U.S. agriculture, including the papaya fruit fly, which is invasive in Florida. A new publication improved the classification of these flies. The papaya fruit fly and six closely related species were previously classified in a separate genus, Toxotrypana, but our recent investigation of their evolutionary relationships showed that they are actually derived species of Anastrepha, the largest and most economically important genus in the American tropics and subtropics. A new publication formally transferred these species, and a petition to the International Commission of Zoological Nomenclature was submitted to validate this action. Normally, the older name (in this case, Toxotrypana) would be adopted for all species, but due to the much greater economic significance of other species of Anastrepha, such action would cause great confusion in scientific communication regarding these flies. This new information already is being used by USDA-APHIS and other regulatory agencies and is being incorporated into an online identification system for these flies.
Review Publications
Savaris, M., Norrbom, A.L., Marinoni, L., Lampert, S. 2019. Revision of the genus Euarestoides Benjamin (Diptera: Tephritidae). Zootaxa. 4551:299-329.
Norrbom, A.L., Barr, N., Kerr, P.H., Mengual, X. 2018. Case 3772 – Anastrepha Schiner, 1868 (Insecta, Diptera, TEPHRITIDAE): Proposed precedence over Toxotrypana Gerstaecker, 1860. The Bulletin of Zoological Nomenclature. 75:165-169.
Norrbom, A.L., Barr, N., Kerr, P.H., Mengual, X., Nolazcon Alvarado, N., Rodriquez, E.J., Steck, G.J., Sutton, B.D., Uramoto, K., Zucchi, R.A. 2018. Synonymy of toxotrypana gerstaecker with anastrepha schiner (Diptera: Tephritidae). Proceedings of the Entomological Society of Washington. 12:834-841.
Scheffer, S.J., Lonsdale, O. 2018. A survey of Agromyzidae (Diptera) reared from leafmines on Long Island, New York; host associations, distribution data, and the description and host association of a new species. Zootaxa. 4450(1):77-90.
