Seed-Feeding Beetles
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Seed-Feeding Beetles (Bruchinae, Curculionidae, Brentidae) from Legumes (Dalea ornata, astragalus filipes) and Other Forbs Needed for Restoring Rangelands of the Intermountain West Author(s): James H. Cane , Clarence Johnson , Jesus Romero Napoles , Douglas A. Johnson and Robert Hammon Source: Western North American Naturalist, 73(4):477-484. 2013. Published By: Monte L. Bean Life Science Museum, Brigham Young University DOI: http://dx.doi.org/10.3398/064.073.0401 URL: http://www.bioone.org/doi/full/10.3398/064.073.0401 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/ terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Western North American Naturalist 73(4), © 2013, pp. 477–484 SEED-FEEDING BEETLES (BRUCHINAE, CURCULIONIDAE, BRENTIDAE) FROM LEGUMES (DALEA ORNATA, ASTRAGALUS FILIPES) AND OTHER FORBS NEEDED FOR RESTORING RANGELANDS OF THE INTERMOUNTAIN WEST James H. Cane1, Clarence Johnson2, Jesus Romero Napoles3, Douglas A. Johnson4, and Robert Hammon5 ABSTRACT.—Seed-feeding beetles of the genera Acanthoscelides, Apion, and occasionally Tychius were commonly found occurring in seeds from wild populations of Astragalus filipes and Dalea ornata across rangelands of the United States Intermountain West, resulting in many new state, county, and host records. These 2 legumes, as well as other perennial herbaceous species, are being commercially farmed to produce seed supplies to rehabilitate sagebrush-steppe and adjoining juniper woodlands following wildfires. Most of the seeds examined in this study hosted one or more seed- feeding beetles; beetles that pupate and overwinter in the seeds pose the risk of being transported to storage ware- houses and distributed to new seedings, unless the beetles are first detected and then controlled. RESUMEN.—Encontramos escarabajos que se alimentan de semillas de los géneros Acanthoscelides, Apion y, ocasion- almente, Tychius en semillas de poblaciones silvestres de Astragalus filipes y Dalea ornata en los pastizales de la zona montañosa del oeste de Estados Unidos, lo cual incrementó los registros en el estado, el condado y de nuevos hués- pedes. Estas dos legumbres y otras especies herbáceas perennes se cultivan a nivel comercial con el fin de producir la reserva de semillas para rehabilitar las estepas de artemisa y los bosques de enebros después de incendios forestales. La mayor parte de las semillas que examinamos en este estudio alojaron a uno o más escarabajos; los que se transforman en pupas y pasan el invierno en las semillas corren el riesgo de ser trasladados a depósitos de almacenamiento y ser dis- tribuidos a nuevas semillas a menos que sean detectados y controlados con anterioridad. Several favorable factors must align for legumes, can be plagued by these seed-feed- flowering plants to sexually reproduce. Some ing beetles (e.g., bean weevil) (Johnson 1981), are intrinsic to the plant (e.g., age, health), and with some Callosobruchus being especially de - others are external, either abiotic (e.g., rain- structive because they can produce multiple fall) or biotic. Among biotic factors, insect generations in dry stored beans and pulse pollinators are often needed for seed produc- crops. tion. Ovule fertilization is no guarantee of suc- Efforts to revegetate or restore degraded cessful reproduction, however, because pre- native plant communities on public range- dispersal frugivores and seed predators often lands have gained momentum in recent years. consume or damage maturing seeds both in Increasing wildfire frequencies fueled by in - agricultural fields and wildland environments vasive annual grasses have devastated native (Crawley 1992). plant communities across millions of hectares Some beetles and wasps are common seed of rangelands in the western United States, predators whose larvae feed within one or sev- impoverishing biodiversity, diminishing forage eral individual seeds. Seed-feeding beetles are for livestock and wildlife, degrading nutrient represented by several taxa: mostly true wee- and water cycles, and accelerating soil erosion vils (Curculionidae) (e.g., Anderson and How- and stream sedimentation (Sheley et al. 2008). den 1994), seed beetles (Chrysomelidae: Bruchi - At these larger spatial scales, planting fire- nae) (particularly Acanthoscelides) (Johnson damaged rangelands with seed is often the 1981), and pear-shaped weevils (Brentidae: sole practical option to improve degraded con- Apioninae) (Kissinger 1968). Crops, especially ditions, speed recovery, and prevent further 1USDA–ARS Pollinating Insect Research Unit, Utah State University, Logan, UT 84322-5310. E-mail: [email protected] 2Deceased. Formerly of the Department of Biology, Northern Arizona University, Flagstaff, AZ. 3Programa de Entomología y Acarología CEIFIT, Colegio de Postgraduados Montecillo, Estado de Mexico, Mexico. 4USDA–ARS Forage and Range Research Lab, Utah State University, Logan, UT 84322-6300. 5Tri River Cooperative Extension, Grand Junction, CO 81502. 477 478 WESTERN NORTH AMERICAN NATURALIST [Volume 73 erosion. Native forb and grass seed is either collection had 18,600 and 22,800 seeds, re - harvested from wildlands, or increasingly, pro- spectively. Site data reported in those studies duced commercially on farms. In their seed included elevation, latitude, and longitude. mixes for revegetation, land managers often Beetles were manually extracted from the prefer a mix of diverse species, including separate seed collections after the seeds were native legumes. Seed-feeding beetles can be air-dried in a greenhouse and mechanically expected to be problematic, given their com- separated from their pods. Additional adult mon association with seeds of sundry forbs, beetles were noted and collected from flowers but scant attention has been given to beetles during a 6-state survey of pollinators at these in native seed crops. Concerns relative to forbs. We also opportunistically collected seed- seed viability for commercial seed production feeding beetles from 1–3 populations of sev- include (1) seed damage, (2) transport of in - eral other prevalent forb genera desired for fested seed to seed growers in other states rehabilitating Great Basin plant communi - where emerging adults could colonize their ties (Hedysarum, Lomatium, and Sphaeralcea). seed fields, and (3) inadvertent transfer into Voucher specimens of the beetles are de - seed storage warehouses where some beetle posited in the insect collections of Utah State species might be able to multiply in stored University and the Smithsonian Institution live seed. National Museum of Natural History. The objective of this study was to survey Evidence for the commercial implications for insect seed predators attacking common of seed crop infestation by seed predators wildflowers of the sagebrush-steppe in the came from a 5-acre field of D. ornata being Intermountain Region of the western United grown for seed in Washington. The grower States. We focused specifically on several spe - sent representative samples of the bulked har- cies of Fabaceae being targeted for commer- vested seed, as well as seed that had been cial seed production through the auspices of cleaned using a gravity table. Seed contents the Great Basin Native Plant Selection and (endosperm vs. weevil) were visualized by Increase Project (GBNPSIP) funded by the digital X-radiography (Faxitron MX-20, 25 KV, USDI Bureau of Land Management (BLM) 30-second exposure), and image interpreta- and administered through the USDA Forest tions were checked with dissected seed. Service, Rocky Mountain Research Station. In this study, we documented the taxonomic RESULTS AND DISCUSSION identities of these seed predators, their host associations and geographic occurrences, and Seed-feeding beetles were prevalent among several pertinent aspects of their life histories. collections of legume seed from the Great Basin. All are minute in size. Among the 22 METHODS bulk seed samples of D. ornata seed examined for seed predators, only 3 lacked adult bee - We used locality data from herbarium speci - tles altogether. Most D. ornata sites across mens to help find populations of basalt milk - the sampled 3-state region yielded mixed vetch (Astragalus filipes Torr. ex A. Gray) from seed infestations of both Apion amaurum Kiss - which to collect seeds. We manually collected inger and Acanthoscelides oregonensis John- and bulked mature seed pods from at least son (Fig. 1, Table 1; Cane et al. 2012). At the 100 plants for each of 67 individual wildland 29 sites where sampled populations of As. fil- sites in July and August 2003 (Bhattarai et ipes hosted seed-feeding beetles, only one al. 2008). These sites collectively represent seed-feeding beetle species, Ac.