Ground Beetles (Coleoptera: Carabidae) of the Prairie Grasslands of Canada
Total Page：16
File Type：pdf, Size：1020Kb
1 Chapter 1 Ground beetles (Coleoptera: Carabidae) of the Prairie Grasslands of Canada Neil J. Holliday1, Kevin D. Floate2, Héctor Cárcamo2, Darren A. Pollock3, Anita Stjernberg1, and Robert E. Roughley1, 4 1Department of Entomology, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2; 2Agriculture and Agri-Food Canada, Lethbridge Research Centre, 5403 - 1 Avenue South, P.O. Box 3000, Lethbridge, Alberta, Canada T1J 4B1; 3Department of Biology, Eastern New Mexico University, Station 33, 1500 S Ave K, Portales, New Mexico, U.S.A. 88130; 4Deceased. Abstract. Carabid beetles are among the best-known of Canada’s insect families and are important indicators of environmental condition and change. Reasons for the relatively good level of knowledge include excellent taxonomic resources, a compendium of ecological information, and up-to-date checklists. The biology of carabid beetles is well understood in general terms, although for most species of the Prairies Ecozone, detailed studies of life cycles are lacking. Although pitfall traps are by far the most prevalent method of sampling, interpretation of trap catches without knowledge of life cycles can be misleading. Information from the literature on patterns of distribution, habitat use, and diet is tabulated for the 398 species of Carabidae (including Cicindelinae) reported to occur in the Prairies Ecozone, and more detailed information is presented on 15 tribes of particular interest. A brief summary is presented of 31 published and unpublished faunistic studies of carabid beetles in the Prairies Ecozone and in cultivated habitats in adjacent ecoregions. For 15 of these studies, relative abundance data are presented and discussed, and three studies, presenting previously unpublished information, are described in detail. An assessment of research gaps reveals that, in the Prairies Ecozone, there have been no studies of the carabid fauna of the Fescue Grassland or Cypress Upland ecoregions, or of Manitoba’s Boreal Transition Ecoregion. Similarly, there have been no studies in the grasslands of the Peace River Boreal Plains of Alberta and British Columbia. Most faunistic studies of carabids have been in annual crop ecosystems. The carabid assemblages in grazing ecosystems, undisturbed native prairie, and woodland habitats are under-researched in the Prairies Ecozone. Of particular concern, given that 53% of the Prairies Ecozone species are associated with wetlands or water bodies, is the absence of faunistic studies of carabids in these disappearing habitats. Detailed biological studies of more carabid species are recommended. Such studies can serve as the basis for future conservation efforts and aid in the interpretation of trap catches. The prevalence of carabids in urban environments provides an opportunity to increase appreciation of arthropod diversity and importance among the influential urban electorate, thus paving the way for future habitat conservation. Résumé. Les carabidés forment une des familles d’insectes les mieux connues du Canada et constituent des indicateurs importants de l’état de l’environnement et de son évolution. L’excellence des ressources taxonomiques, l’existence d’un recueil d’informations écologiques et une liste de contrôle à jour expliquent pourquoi ce groupe est relativement bien connu. Même si on connaît assez bien la biologie générale des carabidés, les cycles de vie de la plupart des espèces de l’écozone des prairies n’ont toujours pas fait l’objet d’études détaillées. Le recours aux pièges à fosse constitue de loin la méthode la plus fréquente d’échantillonnage, mais à défaut d’une connaissance du cycle de vie, l’interprétation des résultats de ce type d’échantillonnage peut être trompeuse. Ce chapitre compile les informations glanées dans la documentation scientifique sur les tendances de la répartition, l’utilisation de l’habitat et le régime alimentaire des 398 espèces de Carabidae (y compris les Cicindelinae) répertoriées dans l’écozone des prairies, en insistant sur 15 tribus d’intérêt particulier. Il résume brièvement 31 études publiées ou Holliday, N. J., K. D. Floate, H. Cárcamo, D. A. Pollock, A. Stjernberg, and R. E. Roughley. 2014. Ground beetles (Coleoptera: Carabidae) of the Prairie Grasslands of 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. 1-85. © 2014 Biological Survey of Canada. ISBN 978-0-9689321-7-9 doi: http://dx.doi.org/10.3752/9780968932179.ch1 2 N. J. Holliday, K. D. Floate, H. Cárcamo, D. A. Pollock, A. Stjernberg, and R. E. Roughley non portant sur les carabidés de l’écozone des prairies et des habitats cultivés des écorégions voisines. Il examine les données sur l’abondance relative présentées dans 15 de ces études, et décrit en détail les résultats jusqu’ici inédits de trois de ces études. Une évaluation des lacunes des connaissances révèle que les carabidés de deux écorégions de l’écozone des prairies — la prairie à fétuque et les hautes terres Cypress — et de l’écorégion de la transition boréale, au Manitoba, n’ont fait l’objet jusqu’ici d’aucune étude. Il en va de même pour les prairies de la rivière de la Paix, dans la plaine boréale de l’Alberta et de la Colombie-Britannique. La plupart des études ont été réalisées sur des écosystèmes faisant l’objet de cultures annuelles. Les communautés d’espèces de carabidés des écosystèmes de pâturage, des prairies indigènes non perturbées et des habitats boisés restent insuffisamment étudiées dans l’écozone des prairies. L’absence d’études sur la faune des carabidés des terres humides et des milieux aquatiques préoccupe particulièrement compte tenu du fait que ces habitats en voie de disparition abritent 53 % des espèces de l’écozone des prairies. On recommande qu’un nombre plus grand d’espèces de carabidés fassent l’objet d’études biologiques détaillées. De telles études peuvent servir de point de départ aux futurs efforts de conservation, et faciliter l’interprétation des résultats des échantillonnages effectués à l’aide de pièges à fosse. La présence généralisée des carabidés dans les milieux urbains offre l’occasion de promouvoir une plus grande appréciation de la diversité des arthropodes et de leur importance auprès de l’électorat urbain influent et de paver ainsi la voie aux futurs projets de conservation de l’habitat. Introduction Carabid beetles are among the best-studied arthropods in North America, and they have been extensively used as ecological indicator species. Two reasons for their popularity for study are that there are excellent taxonomic resources for Canadian species and that carabid beetles are easy to catch with pitfall traps. As ecological indicators, they have the property of being sensitive to environmental conditions and, because they have a general diet, their distribution is not simply a proxy for the distribution of their food. Depending upon species, diets of carabid beetles are broad and may span several trophic levels, thus enhancing the value of these insects as sensitive indicators of environmental disturbance. The intent of this chapter is to present an overview of the current knowledge of the carabid beetles of the Prairies Ecozone of Canada, as defined by Shorthouse (2010b). The chapter places particular emphasis on the biodiversity of the group and highlights a number of faunistic studies of carabid beetles in the ecozone. Many of these studies are published in scientific journals, but several are unpublished theses of which most readers will be unaware. The chapter begins with a general introduction to the biology of the Carabidae, followed by a review gathered from published sources of the distribution and ecology of all species reported to have been collected in the Prairies Ecozone. Three detailed treatments of faunistic studies follow, and then we summarize all of the published and unpublished studies of the carabid fauna in the ecozone that are known to us. We conclude with an assessment of gaps in knowledge and suggest future actions to further knowledge and conservation of the carabid fauna. Overview of Carabidae Systematics and Taxonomy The order Coleoptera, the beetles, is the most speciose order of insects on the planet. Adult beetles are characterized morphologically by the hardening of the forewings as elytra (Maddison 2000). There are four suborders of extant beetles, of which the largest two are the Polyphaga and the Adephaga. Their names are derived from the general characteristics of their diet, although members of the suborders are distinguished morphologically (Maddison 2000). Families of the Adephaga, the second largest suborder, are usually divided into the Ground beetles (Coleoptera: Carabidae) of the Prairie Grasslands of Canada 3 aquatic Hydradephaga and the terrestrial Geadephaga, and it is within the Geadephaga that the family Carabidae, the ground beetles, is placed (Bousquet 2012). Systematists do not agree on the division of Geadephaga into families, and Bousquet (2012) provides an excellent review of the subject. In this chapter, we have followed Bousquet (2012) in including the tiger beetles as a subfamily, Cicindelinae, within the family Carabidae, but have excluded the Rhysodidae and Trachypachidae from our treatment. Within the Carabidae, the division into tribes (in the sense of Lindroth 1961–1969 and Bousquet 2012) is relatively stable, as is the generic composition of each tribe. However, even before the advent of molecular techniques, there was considerable debate about evolutionary relationships among tribes (Ball 1979) and, as summarized in Bousquet (2012), the incorporation of molecular information with older morphological studies has not yet resulted in consensus. Bousquet (2012) provides an up-to-date account of the status of classification and nomenclature of Carabidae in North America, and the reader is referred there for a comprehensive treatment of the topic. In this chapter, we have followed the nomenclature and tribal classification of Bousquet’s (2012) catalogue. We have generally not referred to subspecies as, in many of the studies covered, beetles were not identified to the subspecific level.