Location: Systematic Entomology Laboratory
2017 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 Anastrepha, the largest and most economically important group of fruit flies in the American tropics, included: publication of new molecular markers to distinguish the Caribbean fruit fly, publication of new distribution, host plant, and taxonomic data for two species in Brazil, further development of an electronic identification tool for the nearly 300 species of this group, and collection of additional samples for DNA analysis. A molecular analysis of the evolutionary relationships within Anastrepha, based on 6 DNA regions and 159 species, was published. Additional new information was published for species in another group of fruit flies that includes pests of apple, cherries, blueberries, tomato and eggplant, and a host plant list for the apple maggot fly was developed in collaboration with APHIS. Data from additional publications were added to names and host plant databases for fruit flies, and progress was made to serve this information on an APHIS-CPHST web site. This information is critical to APHIS-PPQ and other regulatory agencies to prevent the spread of pest species into the U.S.
Molecular systematic and ecological analysis of pest leaf-mining, galling, and fruit flies, and their parasitoids. Primers necessary for DNA sequencing were designed for both mitochondrial and nuclear genes in a variety of plant-feeding groups of flies and their associated parasitoids. Specifically, these specialized primers have been designed for leaf-mining flies (Liriomyza, Phytomyza) that are pests of fruit and vegetables, fruit flies (Blepharoneura) that breed in pumpkins and relatives (Cucurbitaceae), and for braconid and other wasp parasitoids attacking these groups. Molecular analysis of ecological associations and host-specificity in parasitoids attacking holly leaf-mining flies was completed. Data collection is continuing on leaf-mining pests and related groups in order to better understand species limits, ecological interactions, and host ranges of the plant pests and their parasitoids. This information is critical to effective management of pest populations 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, 2016 to June 16, 2017, 842 submittals were identified, including 509 "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. Current identification capabilities are based mainly on adult morphology, sometimes of only one sex, and the larvae, the stage most commonly intercepted at ports of entry, are difficult if not impossible to identify. Scientists from USDA-ARS, USDA-APHIS-CPHST, Departments of Agriculture from California and Florida, several universities, and international collaborators are working to develop new diagnostic tools to more rapidly and reliably identify all life stages of fruit flies, by studying the morphology and DNA of the adults and larvae. A new study of evolutionary relationships within the largest group of fruit flies in the Americas, including pests like the Mexican, West Indian, South American and Caribbean fruit flies, provides a framework for ongoing diagnostic studies and significantly builds the data library of DNA sequences critical to reliable identification of the pest. It also shows that a small morphologically derived group that includes the papaya fruit fly should be included within this group. This new information already is being used by USDA to identify specimens captured in detection programs and at ports of entry and is extremely valuable to regulatory agencies such as APHIS-PPQ in limiting the spread of fruit fly pests.
Review Publications
Adaime, R., Jesus-Barros, C.R., Uramoto, K., Norrbom, A.L., Zucchi, R.A. 2016. First record of Anastrepha zacharyi Norrbom (Diptera, Tephritidae) in Brazil, and notes on its host plant and parasitoid. Proceedings of the Entomological Society of Washington. 118:636-640.
Barr, N., Ruiz-Arce, R., Obregon, O., Shatters, R.G., Norrbom, A.L., Nolazco, A., Thomas, D.B. 2017. Diagnostic characters within ITS2 DNA support molecular identification of Anastrepha suspensa. Florida Entomologist. 100:182-185.
Hebert, J.B., Scheffer, S.J., Hawthorne, D.J. 2016. Evidence for ecological speciation via a host shift in the holly leafminer, Phytomyza glabricola (Diptera: Agromyzidae). Molecular Ecology. 6:6565-6577.
Ottens, K., Winkler, I.S., Lewis, M.L., Scheffer, S.J., Gomes-Costa, G.A., De V. Barbosa, M.R., Condon, M.A., Forbes, A.A. 2017. Genetic differentiation associated with host plants and geography among six widespread lineages of South American Blepharoneura fruit flies (Tephritidae). Journal of Evolutionary Biology. 30:696-710.
Schutze, M.K., Virgilio, M., Norrbom, A.L., Clarke, A.R. 2017. Integrative taxonomy: Where we are now, with a focus on the resolution of three tropical fruit fly species complexes. Annual Review Of Entomology. 62:147-64.
Weintraub, P.G., Scheffer, S.J., Visser, D., Valladares, G., Soares, C.A., Shepard, B.M., Rauf, A., Murphy, S.T., Mujica, N., Mac Vean, C., Kroschel, J., Kishinevsky, M., Joshi, R.C., Johansen, N.S., Hallette, R., Civelek, H.S., Chen, B. 2017. The invasive Liriomyza huidobrensis (Diptera: Agromyzidae): Understanding its pest status and management globally. Journal of Insect Science. 28:1-27.
Uramoto, K., Norrbom, A.L., Zucchi, R.A. 2016. Redescription, lectotype designation and new records of Anastrepha luederwaldti Lima (Diptera, Tephritidae). Zootaxa. 4168:341-346.
Mengual, X., Kerr, P., Norrbom, A.L., Barr, N., Lewis, M.L., Stapelfeldt, A., Scheffer, S.J., Woods, P., Islam, M.S., Korytkowski, C.A., Uramoto, K., Rodriguez, E.J., Sutton, B.D., Nolazco, N., Steck, G.J., Gaimari, S. 2017. Phylogenetic relationships of the tribe Toxotrypanini (Diptera: Tephritidae) based on molecular characters. Molecular Phylogenetics and Evolution. 113:84-112.
