1st Place: Friend, foe, or acquaintance? Interactions between Pterostichus melanarius (Ill.) (Coleoptera: Carabidae) and the pea leaf weevil L. (Sitona lineatus) in pulse agroecosystems

The pea leaf weevil, Sitona lineatus L. (Coleoptera: Curculionidae), is a significant pest of field pea, Pisum sativum L. (Fabaceae), and faba bean, Vicia faba L. (Fabaceae), that has recently invaded the Canadian Prairie Provinces. Various tactics have been investigated for population management; however, there still is no overall integrated pest management (IPM) program to manage S. lineatus in a sustainable manner. Ground beetles (Coleoptera: Carabidae) are among the most diverse and numerous arthropods present in agroecosystems. Various species are omnivorous and form an important component of natural enemy communities for conservation biological control of herbivorous pests. Pterostichus melanarius (Ill.) (Coleoptera: Carabidae) is a ubiquitous, non-native ground beetle that dominates pitfall trap catch in pulse agroecosystems, where S. lineatus is a pest. Pterostichus melanarius is an opportunistic generalist, which feeds primarily on invertebrates, and some plant material. Adult P. melanarius can consume over three times their body weight per day and are thought to aggregate in agricultural fields, where pest densities are high. The objective of this study was to test the effect of S. lineatus density on feeding rates of P. melanarius in a laboratory assay, and to estimate the half-life digestion time of S. lineatus DNA in the gut content of P. melanarius. Results from this study will determine the potential role of P. melanarius as a natural enemy of S. lineatus in its expanded range and aid in the development of an IPM program for S. lineatus population management in Alberta.