Beetles in this family are generally predaceous, and this particular species has been observed eating a variety of crop pests. Prey include the western corn rootworm (Diabrotica virgifera virgifera), corn earworm (Helicoverpa zea), black cutworm (Agrotis ipsilon) and armyworm (Pseudoletia unipuncta) (Lundgren, Duan, Paradise, and Wiedenmann 2005). These rambunctious little guys are definitely on our side. Thankfully this is one of the most abundant ground beetles in agricultural areas of the midwest during the growing season (Lundgren et al. 2005).
Lundgren, J.G., J.J. Duan, M.S. Paradise, and R.N. Wiedenmann. 2005. Rearing Protocol and Life History Traits for Poecilus chalcites (Coleoptera: Carabidae) in the Laboratory. J. Entomol. Sci. 40(2): 126-135.