Exposure to a glyphosate-based herbicide affects agrobiont predatory arthropod behaviour and long-term survival Samuel C. Evans • Emma M. Shaw • Ann L. Rypstra Accepted: 2 June 2010 / Published online: 15 June 2010 Ó Springer Science+Business Media, LLC 2010 Abstract Humans commonly apply chemicals to manage agroecosystems. If those chemicals influence the behaviour or survival of non-target arthropods, the food web could be altered in unintended ways. Glyphosate-based herbicides are among the most ubiquitous pesticides used around the world, yet little is known about if and how they might affect the success of terrestrial predatory arthropods in agroecosystems. In this study, we quantified the effects of a commercial formulation of a glyphosate-based herbicide on the activity of three predatory arthropod species that inhabit agricultural fields in the eastern United States. We also measured the survival of the most common species. We tested the reactions of the wolf spider, Pardosa mil- vina, to either direct application (topical) or contact with a treated substrate (residual). We quantified the reactions of a larger wolf spider, Hogna helluo, and a ground beetle, Scarites quadriceps, to a compound (topical plus residual) exposure. Pardosa milvina reduced locomotion time and distance under topical herbicide exposure, but increased speed and non-locomotory activity time on exposed sub- strate. Both H. helluo and S. quadriceps increased non- locomotory activity time under compound herbicide exposure. Over a period of 60 days post-exposure, residu- ally exposed P. milvina exhibited lower survivorship compared to topically exposed and control groups. Thus, exposure of terrestrial arthropods to glyphosate-based herbicides affects their behaviour and long-term survival. These results suggest that herbicides can affect arthropod community dynamics separate from their impact on the plant community and may influence biological control in agroecosystems. Keywords Glyphosate Á Herbicide Á Agroecosystem Á Activity Á Survival Á Wolf spider Á Biocontrol Á Ground beetle Introduction Glyphosate-based herbicides are the most commonly used herbicides worldwide, largely because they are considered effective at killing weeds, safe to users, and viewed to be minimally harmful to the environment (Pan 1996; Baylis 2000; Woodburn 2000; Lundgren et al. 2009). Thus far, the few existing studies on terrestrial arthropods reveal few lethal effects of exposure to these herbicides (Bramble et al. 1997; Giesy et al. 2000; Haughton et al. 2001a; Lindsay and French 2004; Michalkova ´ and Peka ´r 2009; Benamu ´ et al. 2010). However, the increasingly heavy use of these herbicides, facilitated by the introduction of genetically modified resistant crop plants, has contributed to the decline of agrobiont arthropod diversity in recent decades (Cane and Tepedino 2001; Benton et al. 2003; Thorbek and Bilde 2004). Early studies suggest that her- bicide application drives changes in arthropod population dynamics via changes in vegetation structure (Brust 1990; Haughton et al. 1999, 2001b, 2003; Bell et al. 2002; Roy et al. 2003; Jackson and Pitre 2004) and availability of alternative prey (Asteraki et al. 1992). S. C. Evans Department of Zoology, Miami University, Oxford, OH 45056, USA E. M. Shaw Department of Environmental and Geographical Sciences, Manchester Metropolitan University, Manchester M1 5GD, UK A. L. Rypstra (&) Department of Zoology, Miami University, Hamilton, OH 45011, USA e-mail: rypstral@muohio.edu 123 Ecotoxicology (2010) 19:1249–1257 DOI 10.1007/s10646-010-0509-9