Consumption evaluation of weed seeds by Notiobia (Anisotarsus) cupripennis(Germ.) (Coleoptera : Carabidae)

The food preference of Notiobia cupripennis among seeds of eight weedy spri ng-summer species (Sp-Su) and six autumn-winter (Av-Wi) species more common in the agroecosystems of the South of Santa Fe Province, Argentina, was es timated in this study. The seeds of the species of each group were offered simultaneously and in pairs to adults individually placed. The relation (da maged seeds/available seeds) x 100 of each species was considered as a food preference index. The data were analysed by analysis of variance and Dunca n's Multiple Range Test and by a paired difference test, previous arcsine-s quare-root transformation. The seeds of the Av-Wi species were more damaged (27.65%) than the Sp-Su ones (10.40%). Highly significative differences in the percentage of damaged seeds among the different species were found; di cotyledones were preferred over gramines. The food preference ranking was m aintained when the insects were forced to choose between the seeds of two w eed species. The food preference would be attributed to differences in seed size, tegument toughness and chemical composition of the seeds in relation to the ability of handling the seeds and the nutritional requirements of t he insect.