Bees increase seed set of wild plants while the proportion of arable land has a variable effect on pollination in European agricultural landscapes

Background and aims - Agricultural intensification and loss of farmland heterogeneity have contributed to population declines of wild bees and other pollinators, which may have caused subsequent declines in insect-pollinated wild plants. Material and methods - Using data from 37 studies on 22 pollinator-dependent wild plant species across Europe, we investigated whether flower visitation and seed set of insect-pollinated plants decline with an increasing proportion of arable land within 1 km. Key results - Seed set increased with increasing flower visitation by bees, most of which were wild bees, but not with increasing flower visitation by other insects. Increasing proportion of arable land had a strongly variable effect on seed set and flower visitation by bees across studies. Conclusion - Factors such as landscape configuration, local habitat quality, and temporally changing resource availability (e.g. due to mass-flowering crops or honey bee hives) could have modified the effect of arable land on pollination. While our results highlight that the persistence of wild bees is crucial to maintain plant diversity, we also show that pollen limitation due to declining bee populations in homogenized agricultural landscapes is not a universal driver causing parallel losses of bees and insect-pollinated plants.Peer reviewe

Increasing crop heterogeneity enhances multitrophic diversity across agricultural regions

International audienceAgricultural landscape homogenization has detrimental effects on biodiversity and key ecosystem services. Increasing agricultural landscape heterogeneity by increasing seminatural cover can help to mitigate biodiversity loss. However, the amount of seminatural cover is generally low and difficult to increase in many intensively managed agricultural landscapes. We hypothesized that increasing the heterogeneity of the crop mosaic itself (hereafter “crop heterogeneity”) can also have positive effects on biodiversity. In 8 contrasting regions of Europe and North America, we selected 435 landscapes along independent gradients of crop diversity and mean field size. Within each landscape, we selected 3 sampling sites in 1, 2, or 3 crop types. We sampled 7 taxa (plants, bees, butterflies, hoverflies, carabids, spiders, and birds) and calculated a synthetic index of multitrophic diversity at the landscape level. Increasing crop heterogeneity was more beneficial for multitrophic diversity than increasing seminatural cover. For instance, the effect of decreasing mean field size from 5 to 2.8 ha was as strong as the effect of increasing seminatural cover from 0.5 to 11%. Decreasing mean field size benefited multitrophic diversity even in the absence of seminatural vegetation between fields. Increasing the number of crop types sampled had a positive effect on landscape-level multitrophic diversity. However, the effect of increasing crop diversity in the landscape surrounding fields sampled depended on the amount of seminatural cover. Our study provides large-scale, multitrophic, cross-regional evidence that increasing crop heterogeneity can be an effective way to increase biodiversity in agricultural landscapes without taking land out of agricultural production

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Die transnationale Verlagsbuchhandlung Treuttel & Würtz (1750-1850)

La maison d’édition et de librairie Treuttel & Würtz a joué un rôle décisif dans les échanges internationaux au tournant des XVIIIe / XIXe siècles. c étaient non seulement les éditeurs de B. Constant, J. W. Goethe et G. de Staël, mais aussi les fournisseurs des grandes bibliothèques européennes en publications venant de l’étranger (p. ex. les bibliothèques royales à Paris, Berlin et Londres, la bibliothèque du marquis de Paulmy, celle de Weimar et celle de l’université de Göttingen). L’essor de la maison est lié à la nouvelle conception de l’image du libraire à Strasbourg à l’époque des Lumières : il est le médiateur entre l’auteur et le public, et entre les différentes cultures entre lesquelles il anime un marché du livre transnational. D’origine strasbourgeoise et avec des établissements à Strasbourg, Paris et Londres, les dirigeants de Treuttel & Würtz répondent pleinement à ce modèle. La valorisation du livre et de son contenu, et la relation étroite entretenue avec l’élite culturelle et politique de l’époque, leur ont permis de bénéficier de privilèges extraordinaires, dont une licence de commerce avec l’Angleterre sous l’Empire, et un intéressement dans la création de nouvelles bibliothèques publiques. Par leur intégration aux élites de l’université et de la culture, ils ont pu encourager les discours littéraires transculturels, et la naissance des philologies modernes. Cette thèse est conçue dans une perspective interdisciplinaire : elle articule l’histoire du livre, l’histoire transnationale et l’histoire des transferts avec l’histoire littéraire, et elle ouvre la monographie d’une maison d’édition vers un tableau socioculturel de l’Europe autour de 1800.The international bookselling company Treuttel & Würtz played a crucial role in intercultural exchange. It has not only published numerous authors of the French Académie française, and other important writers such as J. W. Goethe or G. de Staël, but also supplied foreign books to prestigious libraries (for example the Royal Libraries in France, Prussia and Great Britain or the Bodleian Library in Oxford). Establishing close ties with the political and cultural elites of the time, the company benefited from unique privileges such as a trade license with the United Kingdom during Napoléon’s continental system. Originally from Strasbourg and perfectly bilingual, the founders continuously expanded the company: in addition to the already existing branch in Strasbourg, they opened a second one in Paris in 1796, and a third in London in 1817. The partners considered the international exchange as their personal vocation and used the medium of the book to materialize their commitment. In this sense, they also devoted their publishing house to the service of the exchange of social and political ideas, literature, and philosophy. Treuttel and Würtz’s commitment to the transnational literary discourse ultimately also influenced the formation of new academic fields around 1800 such as the modern philologies. This thesis builds on an interdisciplinary perspective by combining the French tradition of Book History, with transnational approaches, Cultural Transfer and Romance Studies

Hass_et_al_bumblebee_data

This file includes the data for the bumble bee colonies and their weight gain in the different landscapes as well as the pollen types identified in each pollen sample

Data from: Maize-dominated landscapes reduce bumble bee colony growth through pollen diversity loss

1. Bumble bees are important pollinators for a wide range of crops and wild plants. Performance of their colonies depends on pollen and nectar as food resources, but flowering plants are scarce in modern agricultural landscapes. It is well-known that semi-natural habitats can enhance floral resources and bumble bee abundance, but the impact of different crop types and their heterogeneity at the landscape scale remains unclear. 2. We tested the effect of two different crop types (oilseed rape (OSR) and maize) and of configurational (field border density) and compositional heterogeneity (crop diversity) on weight gain of buff-tailed bumble bee colonies (Bombus terrestris) colonies and the pollen diversity collected by them in 20 landscapes in Central Germany. 3. We found that augmenting maize cover had a detrimental effect on pollen diversity collected by the bumble bees, probably due to intensive management resulting in low plant diversity. This low pollen diversity translated into reduced colony growth, since colonies with high pollen diversity gained more weight than colonies with low pollen diversity. 4. In contrast, OSR cover, configurational and compositional heterogeneity did neither affect colony growth nor pollen diversity. However, for OSR the timing of the flowering period was important. When OSR fields had a high flower cover at the end of the OSR blooming period, colonies showed increased growth rates. 5. Synthesis and applications. Our results complement previous laboratory studies by showing that high pollen diversity leads to better colony performance under field conditions. Therefore, the maintenance of floral diversity in agricultural landscapes is crucial to ensure that bumble bees can fulfil their nutritional needs. However, the heterogeneity of crops, at least under the currently very low levels of crop rotation, does not contribute to this aim. In contrast, crop identity and timing of mass-flowering crops turned out to be important factors, as maize reduced pollen resources, while late blooming OSR oilseed rape was beneficial for bumble bee colonies. Hence, maize cover per landscape should be reduced and strategies to enhance landscape wide flower diversity, especially towards and after the end of oilseed rape bloom should be promoted to support bumble bee colonies that provide important pollination services

Data from: Maize-dominated landscapes reduce bumble bee colony growth through pollen diversity loss

1. Bumble bees are important pollinators for a wide range of crops and wild plants. Performance of their colonies depends on pollen and nectar as food resources, but flowering plants are scarce in modern agricultural landscapes. It is well-known that semi-natural habitats can enhance floral resources and bumble bee abundance, but the impact of different crop types and their heterogeneity at the landscape scale remains unclear. 2. We tested the effect of two different crop types (oilseed rape (OSR) and maize) and of configurational (field border density) and compositional heterogeneity (crop diversity) on weight gain of buff-tailed bumble bee colonies (Bombus terrestris) colonies and the pollen diversity collected by them in 20 landscapes in Central Germany. 3. We found that augmenting maize cover had a detrimental effect on pollen diversity collected by the bumble bees, probably due to intensive management resulting in low plant diversity. This low pollen diversity translated into reduced colony growth, since colonies with high pollen diversity gained more weight than colonies with low pollen diversity. 4. In contrast, OSR cover, configurational and compositional heterogeneity did neither affect colony growth nor pollen diversity. However, for OSR the timing of the flowering period was important. When OSR fields had a high flower cover at the end of the OSR blooming period, colonies showed increased growth rates. 5. Synthesis and applications. Our results complement previous laboratory studies by showing that high pollen diversity leads to better colony performance under field conditions. Therefore, the maintenance of floral diversity in agricultural landscapes is crucial to ensure that bumble bees can fulfil their nutritional needs. However, the heterogeneity of crops, at least under the currently very low levels of crop rotation, does not contribute to this aim. In contrast, crop identity and timing of mass-flowering crops turned out to be important factors, as maize reduced pollen resources, while late blooming OSR oilseed rape was beneficial for bumble bee colonies. Hence, maize cover per landscape should be reduced and strategies to enhance landscape wide flower diversity, especially towards and after the end of oilseed rape bloom should be promoted to support bumble bee colonies that provide important pollination services

Maize-dominated landscapes reduce bumblebee colony growth through pollen diversity loss

Bumblebees are important pollinators for a wide range of crops and wild plants. Performance of their colonies depends on pollen and nectar as food resources, but flowering plants are scarce in modern agricultural landscapes. It is well-known that semi-natural habitats can enhance floral resources and bumblebee abundance, but the impact of different crop types and their heterogeneity at the landscape scale remains unclear. We tested the effect of two different crop types (oilseed rape [OSR] and maize) and of configurational (field border density) and compositional heterogeneity (crop diversity) on weight gain of buff-tailed bumblebee colonies (Bombus terrestris) and the pollen diversity collected by them in 20 landscapes in Central Germany. We found that augmenting maize cover had a detrimental effect on pollen diversity collected by bumblebees, probably due to intensive management resulting in low plant diversity. This low pollen diversity translated into reduced colony growth, since colonies with high pollen diversity gained more weight than colonies with low pollen diversity. In contrast, OSR cover and configurational and compositional heterogeneity did neither affect colony growth nor pollen diversity. However, for OSR, the timing of the flowering period was important. When OSR fields had a high flower cover at the end of the OSR blooming period, colonies showed increased growth rates. Synthesis and applications. Our results complement previous laboratory studies by showing that high pollen diversity leads to better colony performance under field conditions. Therefore, the maintenance of floral diversity in agricultural landscapes is crucial to ensure that bumblebees can fulfil their nutritional needs. However, the heterogeneity of crops, at least under the currently very low levels of crop rotation, does not contribute to this aim. In contrast, crop identity and timing of mass-flowering crops turned out to be important factors, as maize reduced pollen resources, while late blooming oilseed rape (OSR) was beneficial to bumblebee colonies. Hence, maize cover per landscape should be reduced and strategies to enhance landscape wide flower diversity, especially towards and after the end of oilseed rape bloom, should be promoted to support bumblebee colonies that provide important pollination services