Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Ground-dwelling weevil (Coleoptera: Curculionidae) communities in fragmented and continuous hardwood forests in south-central Ontario.

Abstract

Weevils (Coleoptera: Curculionidae) are the largest family in the animal kingdom and can be found in any habitat where plants grow. Many species not native to North America have invaded both anthropogenic and natural habitats, and the aim of this paper is to determine whether forest landscape continuity has discouraged introduced species. We compared the ground-dwelling weevil communities of hardwood forest fragments to those in hardwood stands in a continuously forested landscape, with the prediction that the fragments would have more introduced species. Pitfall traps caught 5090 individuals from 26 species. Both landscapes were dominated by introduced weevils (96% of all individuals), but forest fragments were dominated by Barypeithes pellucidus (Boheman), while Sciaphilus asperatus (Bonsdorff) represented 74% of all weevils caught in the continuous forest. Sixty-four percent of the introduced species were parthenogenetic, and all parthenogenetic species were polyphagous and flightless. Fifteen native species were captured but they accounted for only 4% of total individuals, and the only numerous native species, Hormorus undulatus (Uhler), was absent from the continuous forest. Seven native species were each represented by a single individual, one of which, Sirocalodes sericans (LeConte) is the first record for Ontario. Ground-dwelling weevil communities in central Ontario's forests are composed largely of non-native species, and relatively intact forests do not provide conservation protection for this group of invertebrates.