CAB Reviews 2016 11, No. 044 Non-target effects of insect biocontrol agents and trends in host specificity since 1985 Roy Van Driesche*1 and Mark Hoddle2 Address: 1 Department of Environmental Conservation, University of Massachusetts, Amherst, MA 01003-9285, USA. 2 Department of Entomology, University of California, Riverside, CA 92521, USA. *Correspondence: Roy Van Driesche, Email:
[email protected] Received: 6 October 2016 Accepted: 7 November 2016 doi: 10.1079/PAVSNNR201611044 The electronic version of this article is the definitive one. It is located here: http://www.cabi.org/cabreviews © CAB International 2016 (Online ISSN 1749-8848) Abstract Non-target impacts of parasitoids and predaceous arthropods used for classical biological control of invasive insects include five types of impact: (1) direct attacks on native insects; (2) negative foodweb effects, such as competition for prey, apparent competition, or displacement of native species; (3) positive foodweb effects that benefited non-target species; (4) hybridization of native species with introduced natural enemies; and (5) attacks on introduced weed biocontrol agents. Examples are presented and the commonness of effects discussed. For the most recent three decades (1985–2015), analysis of literature on the host range information for 158 species of parasitoids introduced in this period showed a shift in the third decade (2005–2015) towards a preponderance of agents with an index of genus-level (60%) or species-level (8%) specificity (with only 12% being assigned a family-level or above index of specificity) compared with the first and second decades, when 50 and 40% of introductions had family level or above categorizations of specificity and only 21–27 (1985–1994 and 1995–2004, respectively) with genus or 1–11% (1985–1994 and 1995–2004, respectively) with species-level specificity.