SignificanceDecades of research have fostered the now-prevalent assumption that noncrop habitat facilitates better pest suppression by providing shelter and food resources to the predators and parasitoids of crop pests. Based on our analysis of the largest pest-control database of its kind, noncrop habitat surrounding farm fields does affect multiple dimensions of pest control, but the actual responses of pests and enemies are highly variable across geographies and cropping systems. Because noncrop habitat often does not enhance biological control, more information about local farming contexts is needed before habitat conservation can be recommended as a viable pest-suppression strategy. Consequently, when pest control does not benefit from noncrop vegetation, farms will need to be carefully comanaged for competing conservation and production objectives.

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Honeybees (Apis mellifera L.) have great potential for detecting and monitoring environmental pollution, given their wide-ranging foraging behaviour. Previous studies have demonstrated that concentrations of metals in adult honeybees were significantly higher at polluted than at control locations. These studies focused at a limited range of heavy metals and highly contrasting locations, and sampling was rarely repeated over a prolonged period. In our study, the potential of honeybees to detect and monitor metal pollution was further explored by measuring the concentration in adult honeybees of a wide range of trace metals, nine of which were not studied before, at three locations in the Netherlands over a 3-month period. The specific objective of the study was to assess the spatial and temporal variation in concentration in adult honeybees of Al, As, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Sb, Se, Sn, Sr, Ti, V and Zn. In the period of July–September 2006, replicated samples were taken at 2-week intervals from commercial-type beehives. The metal concentration in micrograms per gram honeybee was determined by inductive coupled plasma–atomic emission spectrometry. Significant differences in concentration between sampling dates per location were found for Al, Cd, Co, Cr, Cu, Mn Sr, Ti and V, and significant differences in average concentration between locations were found for Co, Sr and V. The results indicate that honeybees can serve to detect temporal and spatial patterns in environmental metal concentrations, even at relatively low levels of pollution.

Learning processes play a crucial role in the development of the transformative capacity of social innovation actors. This article builds on the recently developed Transformative Social Innovation (TSI) theory to propose a conceptual framework and research agenda for understanding and investigating the roles and limits of network leadership in supporting learning processes that serve to develop the transformative capacity of social innovation. This focus on network leadership is underdeveloped so far in TSI theory. Addressing this research gap also serves to increase the practical relevance of TSI theory to practitioners engaged in network leadership. After presenting a synopsis of TSI theory, we present an overview of the elements of the conceptual framework, which are successively specified throughout the article. First, transformative change is conceptualized, involving three institutional dimensions: depth, width and length. Based on this, a definition of transformative capacity is proposed that addresses change across these three dimensions. We then describe how various types of learning processes can contribute to the development of transformative capacity. Next, we outline the roles of network leadership in supporting these learning processes across various network levels. We conclude with a research agenda for empirically investigating these roles of network leaders as agents for advancing transformative changes for sustainability.