Research Project: Beetle Taxonomy and Systematics Supporting U.S. Agriculture, Arboriculture and Biological Control

Location: Systematic Entomology Laboratory

2019 Annual Report

Objectives
Objective 1: Collect, document and classify Oriental flea beetle genera, analyze their morphological and molecular characters, and assemble characters of value for accurately identifying adults and establishing relationships (NP304, Component 1, Problem Statement 1A). Objective 2: Discover novel morphological and molecular characters for Neotropical longhorned woodboring beetle species and genera and develop new classifications, descriptions, and identification tools based on these discoveries (NP304, Component 1, Problem Statement 1A). Objective 3: Determine the generic limits in at least two weevil groups (palm weevils and citrus root weevils) through a combined analysis of DNA and morphology and develop fully illustrated revisions, identifications keys, and updated classifications and species catalogs based on these studies (NP304, Component 1, Problem Statement 1A). Objective 4: Provide identifications of beetles, including plant-feeders, wood-borers, and others of agricultural, economic and environmental importance (NP304, Component 1, Problem Statement 1A; Component 3, Subcomponent 3B, Problem Statement 3B1).

Approach
Research outlined in the plan will culminate in leading edge diagnostic tools that will allow partners and beneficiaries such as the Animal and Plant Health Inspection Service (APHIS), the Department of Homeland Security, state departments of agriculture, foreign and domestic biological control labs, and researchers, colleagues, and citizens throughout the U.S. and abroad, to accurately identify beetle groups of exceptional importance (flea beetles, longhorned woodborers, and weevils). Accurate species determinations are critical for every biological and systematic study, especially since there may be regulatory actions based on the identifications or biosecurity implications (Gregory, et al., 2005). By broadly providing research outputs the public, teaching workshops, training other researchers, building government databases on invasive and native species, a potential benefit is to help prevent the spread of invasive species. Through these activities, the problem of declining systematic expertise described in the recent Federal Interagency Committee report on Invasive Terrestrial Animals and Pathogens (ITAP, 2008) will be addressed. Beetles important as control agents of weeds and plant pests will be identified and characterized so they can be used effectively by biological control workers. The wealth of new information prepared for poorly known groups of beetles will have a broader effect on other research on biology, ecology, and biodiversity of beetles. The products of the proposed research will include pictorial guides, keys to accurately identify flea beetles, longhorned woodboring beetles, and weevils, and catalogues and databases for these groups. Examples will include identification tools such as a field guide to the Cerambycidae of the Dominican Republic, LucID websites and keys (including Oriental flea beetles; longhorned beetle tribes), and revisions of beetle taxa, including Elaphidion (Cerambycidae), Monomacra (Chrysomelidae), Diaprepres and Compsus (Curculionidae). Other publications will be produced that focus on descriptions of new species of these groups from Asia and the Neotropical Regions. Still other publications will include catalogs (Dryophthorinae, Oriental flea beetle genera). This project will increase beetle representation in the U.S. National Insect Collection, help build the scanned resources as part of the Biodiversity Heritage Library, build photographic type specimen databases, and lead to regional species inventories and catalogs for use in conservation and management of native landscapes and natural habitats.

Progress Report
Progress was made in objectives all of which fall under National Program 304, Component 1, Systematics and Identification, Problem Statement 1A, Insects and Mites. In regards to Objective 1, during the past year, ARS researchers in Washington D.C., (Smithsonian Institution), continued to develop a revisionary study of Oriental flea beetle genera and continued work towards a LucID identification guide for the Oriental flea beetles. Essential morphological structures of flea beetles have been studied and partly illustrated and 25 species previously unknown to science have been discovered, described, and illustrated. This includes hyper diverse genus Chaetocnema with 85 species in the Oriental biogeographic Region. Chaetocnema species identities were reexamined and changes to their classification were made. Five other Oriental flea beetle genera have been reviewed, redescribed and illustrated. Eight genera have been added to a LucID guide and Oriental flea beetle database. A previously unknown spoon-shaped morphological structure has been discovered on the abdomens of males of a single species of a flea beetle genus Lankaphthona. Its potential function as a courtship restraining devise has been discussed. Pioneering study of a previously unknown kind of mimicry has been continued in collaboration with computer scientists and vision engineers from Georgia Tech and evolutionary biologists from Stony Brooke University. Additional funding was necessary to travel and collect material in unrepresented parts of Asia. The resulting publications and database are critical to Animal and Plant Health Inspection Service-Plant Protection Quarantine (APHIS-PPQ) and other regulatory agencies to prevent the spread of pest species into the U.S. and better use biological control agents. Objective 2 has not seen progress during the past year as it was terminated due to a scientist resignation. Objective 3. ARS scientists published a 96-page illustrated synoptic key and comparative morphology study to the 38 known larvae of dryophthorine genera, which contributes substantially to the character coding of larval forms for the phylogenetic analysis of the subfamily. The larvae of seven genera were reported for the first time. This identification tool includes illustrated examples of all 52 morphological characters and detailed line illustrations of the mouthparts of 37 genera. Examination, illustration, and coding of adult morphological characters continues. Research is concluding on a fossil-calibrated molecular phylogeny of Dryophthorinae, based on two molecular markers, 18S and 28S, with colleagues from Harvard University/STRI. Collaboration was initiated with scientists from the University of Memphis to infer the phylogeny and evolution of Dryophthorinae and of Curculionoidea using large-scale phylogenomic data. In addition, and because of collaborative research between NIH, ARS, NOAA, Mali Malaria Research Training Center, University of KwaZulu-Nata, University of Greenwich, and the Smithsonian Institution provided strong evidence for long-distance migration (nightly spans of more than 300 km) of mosquitoes, most of them blood-fed females, and other arthropods using upper air currents in the Sahel. This discovery, based on melded insights from mosquitoes and other insects, transforms our current understanding of the population dynamics of arthropod vectors and pest species and has significant implications for malaria control and eradication as well as global food security and human health. The research manuscript is currently under review in the journal Nature. In addition, ongoing research stemming from this collaboration also suggests specific lineages of weevils utilize precise upper air currents to access seasonal crops/resources in the Sahel. Progress was made in Objective 4, which falls under National Program 304; Component 3, Insects and Mites; Subcomponent 3B, Natural Ecosystems; Problem Statement 3B1, Early detection and prevention of both invasive and native insect and mite pests. During the past year, ARS researchers in Beltsville, Maryland (Smithsonian Institution), completed identifications of beetles, including those intercepted at all ports-of-entry into the U.S., and those submitted to the laboratory by universities and agricultural extension agencies, and entered the data in the Systematic Entomology Laboratory Identification System. Significant numbers of beetle identifications have been made. In the period from October 1, 2018 to May 22, 2019, 1,334 submittal lots (14,992 specimens) were identified, including 899 “urgent”, 435 “prompt" and “routine” submittals for USDA-APHIS-PPQ of specimens intercepted on perishable commodities at ports of entry. “Urgent” identifications (those requiring same day turn-around of specimens intercepted on perishable commodities at ports of entry) have been processed daily as submitted. Obstacles to achieving this milestone include shortness of staff specialists to perform identifications, diversion of scientific staff to perform technical and IT functions due to loss of former positions, and loss of collaborating specialists who formerly handled regular lots for some groups. These identifications are critical to APHIS-PPQ, regulatory agencies, universities and state extension agencies.

Accomplishments
1. Discovering and documenting biological diversity of flea beetles - pests and vectors of bacterial diseases of agriculturally important plants. Flea beetles are among the most important insects for U.S. agriculture as many are serious pests and feed on valuable crops costing billions of dollars in losses annually while others are important biological control agents that can be used to destroy invasive, noxious weeds. ARS researchers in Washington, D.C., in collaboration with scientists in China and India concluded a 9-year study of Hairy Leg flea beetles, a group (genus) many species of which are pests of and transmit bacterial diseases to beat, corn, millet, rice, sugar cane, sweet potato, and wheat. Resulting from extensive field explorations and studies of the major world Natural History collections, all 85 species that occur in the Oriental biogeographic region have been investigated, described, and illustrated. Among them are 19 species that were previously unknown to science. The study deepens our understanding of classification, biology, and diversity of agriculturally important flea beetles and enhance our abilities to recognize invasive beetle pests at the ports of entry and thus prevent them from spreading and establishing in the United States.

2. First comprehensive illustrated identification tool to the larvae of palm weevil genera of the world. Most weevils feed inside plant tissue as larvae and the feeding may weaken and/or eventually kill the plant; also, Dryophthorinae, known as palm weevils, includes important pests worldwide such as the red palm weevil, the South American palm weevil, the New Guinea sugar cane weevil, and three species of banana weevil. Palm weevil larvae are routinely encountered in the field, farm, or ports of entry where they are commonly intercepted and, with few exceptions, remain unidentifiable beyond the level of subfamily; also Morphological features of immature forms in weevils are highly reduced, making identification of larval forms extremely challenging. Specialized methods and expertise are required for accurate identification. ARS scientists in Washington, D.C., completed research that transforms our ability to identify currently known dryophthorine weevil larvae worldwide with the publication of the first, most comprehensive morphological treatment of all but one of the 38 currently known larvae of Dryophthorinae genera representing seven subtribes in four of the five tribes. The data is presented as an easy to use, illustrated synoptic key, which aims to reduce ambiguity and limitations sometimes posed by traditional, single-entry dichotomous keys. The 96-page publication includes 52 fully-illustrated sections and detailed illustrations of all diagnostic features of the mouthparts, as well as salient features of the abdomen, head, and thorax and this easy-to-use identification tool will benefit the scientific community, resource managers, port identifiers, and the general public; in addition, the comparative morphological study of the larvae will serve as a source of data for future and ongoing combined phylogenetic analyses.

Review Publications
Chamorro, M.L., Barclay, M.L. 2018. On the identity of a U.S. intercepted Conotrachelus Dejean (Coleoptera: Curculionidae) on avocado (Persea americana). Biodiversity Data Journal. 6(e26362):1-32.
Chamorro, M.L. 2019. An illustrated synoptic key and comparative morphology of the larvae of Dryophthorinae (Coleoptera, Curculionidae) genera with emphasis on the mouthparts. Diversity. 11(1):1-96.
Micheli, A.Y., Konstantinov, A.S. 2019. A new species of Bonfilsus Scherer 1967 (Coleoptera: Chrysomelidae: Galerucinae: Alticini) from the Dominican Republic. Journal of Insect Biodiversity. 11(1):1-9. https://e.arsnet.usda.gov/sites/NEA/barc/SEL/Manuscript%20Submissions/2019/Konstantinov363308.pdf.