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Subsidized wildflower strips aim at counteracting insect species loss in agricultural landscapes. Little is known yet about their effects on insects that not only feed on pollen and nectar but also hunt for arthropod prey for larval nutrition. Here, we provide new evidence that wildflower strips may benefit the provisioning of larval prey for spider-hunting wasps. Woody semi-natural habitats in central Germany were selected as trap-nest locations along independent gradients in distance to wildflower strips and percentage of grassland in the surrounding landscape. From these nests, spider individuals hunted by wasps of the genus Trypoxylon (Crabronidae) were collected. In addition, spiders were collected in the associated wildflower strips and the similarity between spider communities in nests and in flowering strips was calculated. The similarity of spider communities decreased with the distance to the next wildflower strips, but the percentage of surrounding grasslands modulated this relationship. This concurred with an observed positive effect of grassland on spider species richness in trap nests, especially if wildflower strips were distant from the nests. In contrast, landscape context did not affect spider species richness in wildflower strips. In conclusion, our results suggest that wildflower strips are used by Trypoxylon wasps for hunting spiders as prey for larvae, yet only if strips are close to nesting habitats and well connected by high shares of grassland. Our results substantiate the importance of wildflower strips for species richness and trophic interactions in agroecosystems. [ABSTRACT FROM AUTHOR]

Information about several papers discussed at the conference entitled "Regional Integration in Africa" held in Gieᵦen, Germany on November 7-9, 2008 is presented. Topics include the assessment of regional economic communities (RECs) practice, East African Community (EAC) and African Union (AU) security and the legal integration of the Organisation for the Harmonisation of Business Law in Africa. Moreover, human rights violations have been reviewed in the court.

Agricultural management and vegetation complexity affect arthropod diversity and may alter trophic interactions between predators and their prey. Web-building spiders are abundant generalist predators and important natural enemies of pests. We analyzed how management intensity (tillage, cutting of the vegetation, grazing by cattle, and synthetic and organic inputs) and vegetation complexity (plant species richness, vegetation height, coverage, and density) affect rarefied richness and composition of web-building spiders and their prey with respect to prey availability and aphid predation in 12 habitats, ranging from an uncut fallow to a conventionally managed maize field. Spiders and prey from webs were collected manually and the potential prey were quantified using sticky traps. The species richness of web-building spiders and the order richness of prey increased with plant diversity and vegetation coverage. Prey order richness was lower at tilled compared to no-till sites. Hemipterans (primarily aphids) were overrepresented, while dipterans, hymenopterans, and thysanopterans were underrepresented in webs compared to sticky traps. The per spider capture efficiency for aphids was higher at tilled than at no-till sites and decreased with vegetation complexity. After accounting for local densities, 1.8 times more aphids were captured at uncut compared to cut sites. Our results emphasize the functional role of web-building spiders in aphid predation, but suggest negative effects of cutting or harvesting. We conclude that reduced management intensity and increased vegetation complexity help to conserve local invertebrate diversity, and that web-building spiders at sites under low management intensity (e.g., semi-natural habitats) contribute to aphid suppression at the landscape scale.