University of Göttingen

About: University of Göttingen is a education organization based out in Göttingen, Germany. It is known for research contribution in the topics: Population & Gene. The organization has 43851 authors who have published 86318 publications receiving 3010295 citations. The organization is also known as: Georg-August-Universität Göttingen & Universität Göttingen.

Foraging ranges of solitary bees

Abstract: Summary 1 Habitat requirements of solitary bees include nesting sites, food resources and nesting material. We used translocation experiments to establish foraging distances and measured foraging trip duration to analyse how solitary bees cope with the distance between nesting sites and suitable food plants in different habitat types. 2 Maximum foraging distance between nesting site and food patch was 150–600 m for the 16 bee species examined. Foraging distance was correlated positively with body length. Mean foraging trip duration, measured for seven bee species, ranged from 6 to 28 min and was also correlated with body length. In a study of the polylectic species Osmia rufa , we found a significant decrease in foraging trip duration with increasing number of plant species. Logistic regressions showed that the oligolectic Megachile lapponica nested in trap nests with a probability of 50% if the distance between trap nest and food patch was less than 250 m. The oligolectic Chelostoma rapunculi utilized trap nests when the distance to the nearest food patch was less than 300 m. 3 These experiments showed that solitary bees have a rather small foraging range so local habitat structure appears to be of more importance than large-scale landscape structure. All requirements for sustaining viable populations must be within this range. Therefore, it is necessary to maintain and restore a dense network of habitat patches in landscapes to ensure long-term sustainability of wild bee diversity and their ecological function as pollinators.

A global quantitative synthesis of local and landscape effects on wild bee pollinators in agroecosystems

Abstract: Bees provide essential pollination services that are potentially affected both by local farm management and the surrounding landscape. To better understand these different factors, we modelled the relative effects of landscape composition (nesting and floral resources within foraging distances), landscape configuration (patch shape, interpatch connectivity and habitat aggregation) and farm management (organic vs. conventional and local-scale field diversity), and their interactions, on wild bee abundance and richness for 39 crop systems globally. Bee abundance and richness were higher in diversified and organic fields and in landscapes comprising more high-quality habitats; bee richness on conventional fields with low diversity benefited most from high-quality surrounding land cover. Landscape configuration effects were weak. Bee responses varied slightly by biome. Our synthesis reveals that pollinator persistence will depend on both the maintenance of high-quality habitats around farms and on local management practices that may offset impacts of intensive monoculture agriculture.

Axonal neuregulin-1 regulates myelin sheath thickness

Abstract: In the nervous system of vertebrates, myelination is essential for rapid and accurate impulse conduction. Myelin thickness depends on axon fiber size. We use mutant and transgenic mouse lines to show that axonal Neuregulin-1 (Nrg1) signals information about axon size to Schwann cells. Reduced Nrg1 expression causes hypomyelination and reduced nerve conduction velocity. Neuronal overexpression of Nrg1 induces hypermyelination and demonstrates that Nrg1 type III is the responsible isoform. We suggest a model by which myelin-forming Schwann cells integrate axonal Nrg1 signals as a biochemical measure of axon size.