title: A multi-approach study to delineate interactions between carabid beetles and soybean aphids.
abstract: In recent years, the soybean aphid, Aphis glycines Matsumura, has become the most important exotic pest of soybean, Glycine max (L.) Merrill, in North America. Given the significant yield losses that are reported, considerable effort has been expended to characterize the  natural enemy community associated with this pest. Several indigenous and naturalized predators have been identified as potential biological control agents, and these include carabid beetles, an abundant and important family of aphid predators. The objectives of this study were to assess the  incidence of field predation by Pterostichus melanarius (Illiger), the most common carabid species in Québec soybeans, using molecular gut-content analysis, and to quantify its impact on A. glycines populations through laboratory and field cage experiments. Throughout  the growing season between 16.8% (during low aphid density) and 33.7% (at times of high aphid density) of P. melanarius tested positive for aphid DNA. Furthermore, although laboratory feeding trials confirmed that P. melanarius prey on A. glycines, short-term field cage  experiments failed to demonstrate a significant reduction of A. glycines populations by carabid beetles. These results suggest a relatively weak interaction between P. melanarius and A. glycines when pest densities are high, but the high predation rate when aphid densities  are particularly low suggests these natural enemies may function as important early-season predators.
authors: Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 rue Sherbrooke est, Montréal, Québec H1X 2B2, Canada. annabelle.Þrlej@gmail.com
authors: Annabelle
authors: A
authors: Firlej
authors: Josée
authors: J
authors: Doyon
authors: James D
authors: JD
authors: Harwood
authors: Jacques
authors: J
authors: Brodeur
mesh_terms: D000818:Animals; D001042:Aphids; D001517:Coleoptera; D017931:DNA Primers / Q000592:standards; D005260:Female; D005766:Gastrointestinal Contents / Q000737:chemistry; D060434:Herbivory; D008297:Male; D010572:Pest Control, Biological; D011235:Predatory Behavior; D013025:Glycine max
chemical_list: D017931:DNA Primers