Staphylinid beetles are recommended bioindicators for the pre-market environmental risk assessment of genetically modified (GM) insect protected maize expressing the Cry3Bb1 toxin. Our multiannual study is a unique European analysis of a staphylinid community within a 14 ha maize field. GM maize, its near-isogenic hybrid (with or without insecticide treatment), and two other reference hybrids were each grown in five 0.5 ha plots. The opportunity for exposure to Cry toxin from plant residues ploughed into the soil was shown by the presence of saprophagous dipteran larvae that are common prey of predatory staphylinid species and hosts of the parasitoid species. 2587 individuals belonging to 77 staphylinid species were sampled using pitfall traps. Lesteva longoelytrata (31%), Oxypoda acuminata (12%), Aloconota sulcifrons (8%) and Anotylus rugosus (7%) were the most abundant beetles in the field. Bionomics, food specialization, temperature requirements and size group were assigned for 25 most common species. These traits determine the occurrence of staphylinid beetles in the field, the food sources they could utilize and thus also their likely contact with the Cry3Bb1 toxin. Statistical analysis of activity abundance, Rao indices and multivariate analysis of distribution of particular categories of functional traits in the field showed negligible effects of the experimental treatments, including the GM maize, upon the staphylinid community. Staphylinid beetles represent a considerably diverse part of epigeic field fauna with wide food specialization; these features render them suitable for the assessment of environmental safety of GM insect protected maize. However, the availability of prey and the presence of particular staphylinid species and their abundance are highly variable; this complicates the interpretation of the results.

Indicators of diversity (population density, relative number of species and evenness) in ground beetles (Carabidae) and rove beetles (Staphylinidae) in upland rice fields were assessed between 1995 and 1999 at Garoua in the Benue valley in North Cameroon. A total of 4369 beetles belonging to 45 carabid species and 2109 beetles belonging to 31 staphylinid species were caught in pitfall traps. Among the carabid beetles, five species Scarites (Orientolobus) lucidus strigiceps Quedenfeldt, Chlaeniostenus denticulatus elatus (Erichson), Lissauchenius venator (LaFerté), Pheropsophus marginatus (Dejean) and Abacetus crenulatus Dejean, in decreasing order, were dominant. In the staphylinid group, Paederus sabaeus Erichson was the most common, followed by Stenus ravus Puthz and Stenus (Mendicus) senegalensis Bernhauer. The Shannon–Weiner and evenness indices varied slightly from year to year. Diversity values remained relatively low among the staphylinid beetles, revealing that rice fields were underpopulated by this group of polyphagous predators. The features of predatory soil-surface beetles and the role they play as an IPM component in West African rice ecosystems are discussed.