Habitat differences in the food composition of the wasplike spider Argiope bruennichi (Scop.) (Aranei : Araneidae) in Poland

During the last few decades the wasp-like spider Argiope bruennichi Scopoli, 1772 expanded its wide geographical distribution in Europe. In this paper we describe and test differences in the diet composition of the wasp-like spider inhabiting a river valley (traditional habitat) and xerothermic grassland (new habitat) in Poland. From a total of 163 webs of A. bruennichi, 430 prey items were found, mainly insects : Coleoptera, Diptera, Homoptera, Heteroptera, Hymenoptera, Lepidoptera, Mecoptera, Odonata, Orthoptera and Neuroptera. Moreover, a semi digested specimen of the common frog Rana temporaria was recorded. Habitats differed significantly in the percentage distribution of eleven general food categories. Among potential influencing factors the number of caught prey was correlated only with the height of the web hub above the ground. The wasp-like spider is ecologically flexible in the use of novel food spectra and this probably allows the colonisation of new localities, as well as habitats.