143 Chapter 4 Weevils (Coleoptera: Dryophthoridae, Brachyceridae, Curculionidae) of the Prairies Ecozone in Canada Robert S. Anderson Canadian Museum of Nature, P.O. Box 3443, Station D, Ottawa, Ontario, Canada, K1P 6P4 Email: [email protected] Patrice Bouchard* Canadian National Collection of Insects, Arachnids and Nematodes, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario, Canada, K1A 0C6 Email: [email protected] *corresponding author Hume Douglas Entomology, Ottawa Plant Laboratories, Canadian Food Inspection Agency, Building 18, 960 Carling Avenue, Ottawa, ON, Canada, K1A 0C6 Email: [email protected] Abstract. Weevils are a diverse group of plant-feeding beetles and occur in most terrestrial and freshwater ecosystems. This chapter documents the diversity and distribution of 295 weevil species found in the Canadian Prairies Ecozone belonging to the families Dryophthoridae (9 spp.), Brachyceridae (13 spp.), and Curculionidae (273 spp.). Weevils in the Prairies Ecozone represent approximately 34% of the total number of weevil species found in Canada. Notable species with distributions restricted to the Prairies Ecozone, usually occurring in one or two provinces, are candidates for potentially rare or endangered status. Résumé. Les charançons forment un groupe diversifié de coléoptères phytophages et sont présents dans la plupart des écosystèmes terrestres et dulcicoles. Le présent chapitre décrit la diversité et la répartition de 295 espèces de charançons vivant dans l’écozone des prairies qui appartiennent aux familles suivantes : Dryophthoridae (9 spp.), Brachyceridae (13 spp.) et Curculionidae (273 spp.). Les charançons de cette écozone représentent environ 34 % du total des espèces de ce groupe présentes au Canada. Certaines espèces notables, qui ne se trouvent que dans cette écozone — habituellement dans une ou deux provinces — mériteraient d’être désignées rares ou en danger de disparition. Introduction Weevils (Curculionoidea) are one of the most diverse groups of insects. Worldwide, they currently include about 5,800 described genera and 62,000 species (Oberprieler et al. 2007; Slipi´nski´ et al. 2011), most of these in the species-rich family Curculionidae. The total number of existing weevil species has been estimated at about 220,000 (Oberprieler et al. 2007), but it may well be higher as more hyperdiverse tropical genera are comprehensively studied. Anderson, R. S., P. Bouchard, and H. Douglas. 2014. Weevils (Coleoptera: Dryophthoridae, Brachyceridae, Curculionidae) of the Prairies Ecozone in Canada. In Arthropods of Canadian Grasslands (Volume 4): Biodiversity and Systematics Part 2. Edited by D. J. Giberson and H. A. Cárcamo. Biological Survey of Canada. pp. 143-167. © 2014 Biological Survey of Canada. ISBN 978-0-9689321-7-9 doi: http://dx.doi.org/10.3752/9780968932179.ch4 144 R. S. Anderson, P. Bouchard, and H. Douglas In Canada there are nearly 900 species of Dryophthoridae, Brachyceridae, and Curculionidae (Table 1; Bousquet et al. 2013). This temperate fauna is much less diverse at the species level than it is at tropical latitudes, but representatives of most subfamilies extend at least into southern Canada. Weevils feed on virtually all taxa of higher plants and on nearly all plant parts in both terrestrial and freshwater habitats. Although most weevils are closely associated with angiosperms, members of some groups develop more or less exclusively on gymnosperms, especially in the order Pinales (conifers) but also on Cycadales (cycads), Ephedrales, and Gnetales (Oberprieler et al. 2007). Weevil larvae generally feed on stressed, diseased, or dying plant parts, appearing to exploit the short stage between the life and death of plants in which their tissues are no longer strongly defended by chemical deterrents or toxins but still contain sufficient nutrients for rapid larval growth (Oberprieler et al. 2007). Because of their generally strict association with particular species or genera of plants, many weevil species are regarded as major or minor pests of agricultural crops, of the Table 1. Overall diversity of weevils (Dryophthoridae, Brachyceridae, Curculionidae) in Canada and in the Prairies Ecozone. Numbers are also given for each subfamily for the diverse family Curculionidae. Family/Subfamily Genera in Genera in Genera in Species in Species in Species in Canada Prairies Prairies Canada Prairies Prairies (#) Ecozone Ecozone (#) Ecozone Ecozone (#) (%) (#) (%) Dryophthoridae Schönherr, 4 1 25.0 27 9 33.3 1825 Brachyceridae Billberg, 1820 10 6 60.0 19 13 68.4 Curculionidae Latreille, 1802 238 109 45.8 823 273 33.2 Curculioninae Latreille, 1802 33 23 69.7 161 87 54.4 Bagoinae Thomson, 1859 2 2 100.0 13 5 38.5 Baridinae Schönherr, 1836 25 11 44.0 37 14 37.8 Ceutorhynchinae Gistel, 1848 31 24 77.4 85 54 62.8 Conoderinae Schönherr, 1833 4 1 25.0 10 2 20.0 Cossoninae Schönherr, 1825 13 3 23.1 29 4 13.8 Cryptorhynchinae Schönherr, 7 3 42.9 16 6 37.5 1825 Cyclominae Schönherr, 1826 1 1 100.0 26 16 61.5 Entiminae Schönherr, 1823 48 22 45.8 111 37 33.3 Hyperinae Marseul, 1863 2 1 50.0 12 9 75.0 Lixinae Schönherr, 1823 7 5 71.4 28 17 60.7 Mesoptiliinae Lacordaire, 2 1 50.0 20 1 5.0 1863 Molytinae Schönherr, 1823 14 3 21.4 56 7 12.5 Scolytinae Latreille, 1804 48 9 18.8 218 14 6.4 Platypodinae Shuckard, 1839 1 0 0.0 1 0 0.0 252 116 46.0 869 295 33.9 Weevils (Coleoptera: Dryophthoridae, Brachyceridae, Curculionidae) 145 of the Prairies Ecozone in Canada forestry industry, and of ornamental plants (Campbell et al. 1989). Conversely, several species have been successfully used as biological control agents of various noxious weeds around the world (O’Brien 1995), in several cases achieving spectacular success in reducing populations of weeds to negligible levels. Weevils are also important pollinators of certain plants, in particular cycads, palms, and the more primitive lineages of dicotyledonous angiosperms. Weevils are often common as Quaternary fossils and play an important role in our understanding of recent past ecosystems, particularly in Asia and North America (Elias 2010). No previous attempts have been made to document the curculionoid fauna of the Canadian Prairies Ecozone despite it being home to some of the most threatened of Canadian natural habitats and to some rare and potentially endemic species of weevils. Over the years, a number of species of Curculionidae (e.g., Centrinogyna canadensis, Ceutorhynchus dubitans, C. handfordi, C. hearnei, and Asperosoma echinatum) have been described from Canadian prairie localities but not (or rarely) recorded since or elsewhere. Herein we present an overview of the species of Dryophthoridae, Brachyceridae, and Curculionidae recorded from the Prairies Ecozone in the provinces of Alberta, Saskatchewan, and Manitoba. Approach We use data from Bousquet et al. (2013) as the authoritative source for all distribution records of weevils in the provinces and territories of Canada, as well as in Alaska (Table 2). The list in Table 2 does not include all weevil species found in Alberta, Saskatchewan, and Manitoba, but is restricted to species of dryophthorid, brachycerid, and curculionid weevils known or likely to be associated with grassland habitats, as well as wetlands and riparian (or other) parklands within the greater Prairies Ecozone. We do not include species recorded from the Cypress Upland Ecoregion, as this is a discrete outlier of the Montane Cordillera Ecozone that occurs on the lower slopes of the Rocky Mountains to the west. We identify as notable species (see “Systematic Review” section below) those with distributions restricted to the Prairies Ecozone and usually occurring in one or two provinces. These are likely to be endemic to these provinces within Canada and/or may be candidates for potentially rare or endangered status; however, we do acknowledge that their apparent rarity may be an artifact of inadequate collecting, especially for small-sized species that may be highly host specific. Species that cause economic damage to stored products (i.e., Sitophilus spp.) were discussed by White et al. (2011) and are therefore excluded here. We summarize known plant associations, feeding type, and species status as a pest or biological control agent. Weevil classification follows Bousquet et al. (2013). Weevils of the Prairies Ecozone General Biology All weevils associated with the Prairies Ecozone in Canada are phytophagous. Two basic life history patterns can be generalized (Anderson 1993). One has larvae that feed internally on the host plants, mainly on reproductive structures, or in stems, or as leaf miners. These species tend to be host specific. The second pattern, predominantly in the curculionid subfamily Entiminae, has larvae that feed in the soil on the roots of the host plants, sometimes forming chambers in the soil or on the root in which the larvae live. These species tend to be unspecialized in terms of host associations. Across Curculionidae, 146 R. S. Anderson, P. Bouchard, and H. Douglas the first pattern predominates, with most weevils being host specific to varying degrees. Certain genera have specific plant associations (e.g., Ceutorhynchus on Brassicaceae, Tychius on Fabaceae, Dorytomus on Salicaceae) (Anderson 1993). All prairie bark beetle species (curculionid subfamily Scolytinae) are phloeophagous (phloem-feeding) or phloeomycetophagous (feed on both phloem and associated symbiotic fungi) in broadleaved trees, and their larvae develop in parental galleries. Plant taxa most frequently