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Bumblebees (Bombus species) are major pollinators of commercial crops and wildflowers but factors affecting their abundance, including causes of recent population declines, remain unclear. Investigating the ecology of species with expanding ranges provides a potentially powerful means of elucidating these factors. Such species may also bring novel pollination services to their new ranges. We therefore investigated landscape-scale habitat use and foraging preferences of the Tree Bumblebee, B. hypnorum, a recent natural colonist that has rapidly expanded its range in the UK over the past decade. Counts of B. hypnorum and six other Bombus species were made in March-June 2012 within a mixed landscape in south-eastern Norfolk, UK. The extent of different landscape elements around each transect was quantified at three scales (250 m, 500 m and 1500 m). We then identified the landscape elements that best predicted the density of B. hypnorum and other Bombus species. At the best fitting scale (250 m), B. hypnorum density was significantly positively associated with extent of both urban and woodland cover and significantly negatively associated with extent of oilseed rape cover. This combination of landscape predictors was unique to B. hypnorum. Urban and woodland cover were associated with B. hypnorum density at three and two, respectively, of the three scales studied. Relative to other Bombus species, B. hypnorum exhibited a significantly higher foraging preference for two flowering trees, Crataegus monogyna and Prunus spinosa, and significantly lower preferences for Brassica napus, Glechoma hederacea and Lamium album. Our study provides novel, quantitative support for an association of B. hypnorum with urban and woodland landscape elements. Range expansion in B. hypnorum appears to depend, on exploitation of widespread habitats underutilised by native Bombus species, suggesting B. hypnorum will readily co-exist with these species. These findings suggest that management could target bumblebee species with distinctive habitat requirements to help maintain pollination services.

Molecular methods have greatly increased our understanding of the previously cryptic spatial ecology of bumble bees (Bombus spp.), with knowledge of the spatial ecology of these bees being central to conserving their essential pollination services. Bombus hypnorum, the Tree Bumble Bee, is unusual in that it has recently rapidly expanded its range, having colonized much of the UK mainland since 2001. However, the spatial ecology of B. hypnorum has not previously been investigated. To address this issue, and to investigate whether specific features of the spatial ecology of B. hypnorum are associated with its rapid range expansion, we used 14 microsatellite markers to estimate worker foraging distance, nest density, between‐year lineage survival rate and isolation by distance in a representative UK B. hypnorum population. After assigning workers to colonies based on full or half sibship, we estimated the mean colony‐specific worker foraging distance as 103.6 m, considerably less than values reported from most other bumble bee populations. Estimated nest density was notably high (2.56 and 0.72 colonies ha−1 in 2014 and 2015, respectively), estimated between‐year lineage survival rate was 0.07, and there was no evidence of fine‐scale isolation by distance. In addition, genotyping stored sperm dissected from sampled queens confirmed polyandry in this population (mean minimum mating frequency of 1.7 males per queen). Overall, our findings establish critical spatial ecological parameters and the mating system of this unusual bumble bee population and suggest that short worker foraging distances and high nest densities are associated with its rapid range expansion. Unlike many other bumble bee populations, Bombus hypnorum in the United Kingdom has been unequivocally successful, having rapidly expanded its range in recent years. We predict that this range, and hence demographic, expansion is associated with worker foraging over dense resources at a short range. We used neutral genetic markers to assign workers collected from a site in the core of B. hypnorum's new UK range, to reveal a mean colony‐specific worker foraging distance of just 104 m—among the shortest range foraging documented for any Bombus population.

Land-use and land-cover (LULC) changes are major drivers of biodiversity loss in semi-arid regions, such as the Caatinga biome located in the Northeast of Brazil. We investigated landscape dynamics and fragmentation in an area of the São Francisco Valley in the Brazilian Caatinga biome and measured the effect of these dynamics on ecological, functional and structural connectivity over a 33-year period (1985–2018). We calculated landscape connectivity indices based on graph theory to quantify the effect of further agricultural expansion on ecological connectivity at the landscape scale. We used a multicriteria decision analysis that integrates graph-based connectivity indices at the habitat patch scale, combined with an index of human disturbance to identify patches that, if conserved and restored, preserve the connectivity of the landscape most effectively. In the period studied, agriculture increased at a rate of 2104 ha/year, while native Caatinga vegetation decreased at a rate of 5203 ha/year. Both dense and open Caatinga became more fragmented, with the number of fragments increasing by 85.2% and 28.6%, respectively, whilst the average fragment size decreased by 84.8% and 6.1% for dense and open Caatinga, respectively. If agriculture patches were to expand by a 300 m buffer around each patch, the overall ecological connectivity could be reduced by 6–15%, depending on the species’ (small- to mid-size terrestrial vertebrates) mobility characteristics for which the connectivity indices were calculated. We provided explicit spatial connectivity and fragmentation information for the conservation and restoration of the Caatinga vegetation in the studied area. This information helps with conservation planning in this rapidly changing ecosystem.

Agricultural intensification and expansion are the main drivers of biodiversity loss that continue to increase this century, especially in South America. International markets and global policy provide incentives and frameworks to address this, but these are unlikely to be effective unless farmers on the ground are enabled and motivated to respond to them by developing long‐term solutions that fit their production systems and local contexts. Here, we use a multi‐actor transdisciplinary approach to co‐design and test agroecological innovations suitable for intensive, exporting South American fruit farms. We focus on highly biodiverse regions experiencing habitat loss in the Mediterranean and dry tropical forest regions of Chile and Brazil, respectively. The innovations were designed to support local biodiversity without compromising productivity or quality. Fourteen farmers participated throughout the project, covering a total of 4178 ha of intensive table grape, mango and cherry production. All were under pressure from buyers to report action on biodiversity. Farmers worked with researchers and industry representatives through an iterative process of dialogues and workshops to select, co‐design and implement three agroecological innovations: perches for birds of prey, cover crops and native hedgerows. Farmers became engaged in monitoring their effectiveness and redesigning them to suit local contexts. We develop an extensive set of resources for ongoing dissemination, including an online sustainability metric to report the practices carried out. Eight farms continued to implement at least one agroecological innovation beyond the end of the project, motivated by its fit to their management system and their ability to report positive actions in their supply chains. Policy implications . Our model of knowledge co‐production demonstrates how transdisciplinary research in agriculture, fully localised in a particular food‐producing context, can enable farmers in the global South to engage with biodiversity conservation in response to top‐down market signals incentivising sustainability. We argue that many top‐down efforts to enhance the sustainability of food supply chains, whether through market incentives, voluntary codes or trade regulations, require locally based knowledge co‐production, in which multiple stakeholders from agriculture and the food industry can benefit from working with locally based researchers. Read the free Plain Language Summary for this article on the Journal blog. La intensificación y expansión de la agricultura son los principales motores de la pérdida de biodiversidad durante este siglo, especialmente en Sudamérica. Los mercados internacionales y la política global ofrecen incentivos y marcos para abordar esto, pero es poco probable que sean efectivas a menos que los agricultores estén capacitados y motivados para responder a ellos, desarrollando soluciones a largo plazo que se adapten a sus sistemas de producción y contextos locales. En este trabajo, utilizamos un enfoque transdisciplinario de multiples actores para co‐diseñar y probar innovaciones agroecológicas adecuadas para predios de producción frutícola intensivas y exportadoras de Sudamérica. Nos enfocamos en regiones de gran biodiversidad que experimentan pérdida de hábitat, en las regiones mediterránea y de bosque tropical seco de Chile y Brasil, respectivamente. Las innovaciones se diseñaron para apoyar la biodiversidad local sin comprometer la productividad o calidad de la producción. Catorce agricultores participaron en todo el proyecto, abarcando un total de 4.178 ha de producción intensiva de uva de mesa, mango y cereza. Todos estaban mandatados por los compradores para que informaran de las medidas adoptadas en materia de biodiversidad. Los agricultores trabajaron con investigadores y representantes de la industria a través de un proceso iterativo de diálogos y talleres para seleccionar, co‐diseñar e implementar tres innovaciones agroecológicas: perchas para aves rapaces, cultivos de cobertura y setos nativos. Los agricultores se involucraron en monitorear su efectividad y rediseñarlos para adaptarlos a los contextos locales Desarrollamos un amplio conjunto de recursos para la difusión continua, incluida una métrica de sostenibilidad en línea para informar sobre las prácticas implementadas. Ocho predios siguieron aplicando al menos una innovación agroecológica una vez finalizado el proyecto, motivadas por su adecuación a su sistema de gestión y su capacidad para informar de acciones positivas en sus cadenas de suministro. Implicancia política . Nuestro modelo de coproducción de conocimiento demuestra cómo la investigación transdisciplinar en agricultura, localizada en un contexto particular de producción de alimentos, puede permitir a los agricultores del Sur comprometerse con la conservación de la biodiversidad en respuesta a las señales del mercado que incentivan la sostenibilidad. Sostenemos que muchos esfuerzo de arriba hacia abajo para mejorar la sostenibilidad de las cadenas de suministro de alimentos, ya sea a través de incentivos de mercado, códigos voluntarios o regulaciones comerciales, requiere una coproducción de conocimientos basado en el lugar, en la que múltiples partes interesadas de la agricultura y la industria alimentaria pueden beneficiarsr al trabajar con investigadores locales. A intensificação e a expansão agrícola são os principais fatores relacionados à perda de biodiversidade, que continua a aumentar neste século, especialmente na América do Sul. Os mercados internacionais e o cenáriopolítico global fornecem incentivos e estrutura para lidar com este problema, mas é improvável que estes sejam eficazes a menos que os agricultores estejam capacitados e motivados a desenvolver soluções de longo prazo que se adaptem aos seu sistema de produção e contexto local. Aqui, utilizamos a abordagem transdisciplinar envonvedo multiplos atores para co‐desenvolver e testar inovações agroecológicas adequadas a fazendas de fruticultura intensiva e exportadoras da América do Sul. Nós enfocamos áreas com elevada biodiversidade, atingidas por perda de habitat, situadas em região mediterrânea ede floresta tropical seca no Chile e no Brasil, respetivamente. As inovações foram concebidas para apoiar a biodiversidade local sem comprometer a produtividade ou a qualidade. Catorze agricultores participaram do projeto, abrangendo área total de 4.178 ha com produção intensiva de uva de mesa, manga e cereja. Todos estavam sob pressão dos compradores para apresentarem açõesrelacionadas a biodiversidade. Os agricultores trabalharam com pesquisadores e representantes da indústria através de um processo iterativo de diálogo e grupo de trabalho, para selecionar, co‐desenvolver e implementar três inovações agroecológicas: poleiros para aves de rapina, cultivo de cobertura e faixas com plantas nativas. Os agricultores empenharam‐se em monitorar a eficácia e desenvolver adaptações para adequá‐las ao contexto local. Desenvolvemos um conjunto amplo de recursos para divulgação contínua, incluindo uma métrica de sustentabilidade online para comunicar as práticas realizadas. Oito agricultores continuaram a implementar pelo menos uma inovação agroecológica após a finalização do projeto, motivados pela sua adequação ao sistema demanejo e por representar ação positiva para a cadeia de abastecimento. Implicações para as políticas . O nosso modelo de coprodução de conhecimento demonstra como a pesquisatransdisciplinar na agricultura, situada totalmente em um contexto particular de produção de alimentos, pode permitir que os agricultores do Sul global se envolvam na conservação da biodiversidade em resposta a sinais de mercado, de cima para baixo, que incentivam a sustentabilidade. Argumentamos que muitos esforços, de cima para baixo, para melhorar a sustentabilidade das cadeias de abastecimento alimentar, seja através de incentivos de mercado, códigos voluntários ou regulamentos comerciais, requer a coprodução de conhecimentos de base local, na qual vários tomadores de decisão, da agricultura e da indústria alimentar, podem se beneficiar trabalhando com pesquisadores locais. Read the free Plain Language Summary for this article on the Journal blog.

Resource inheritance is a major source of conflict in animal societies. However, the assumptions and predictions of models of conflict over resource inheritance have not been systematically tested within a single system. We developed an inclusive fitness model for annual eusocial Hymenoptera that predicts a zone of conflict in which future reproductive workers are selected to enforce nest inheritance before the queen is selected to cede the nest. We experimentally tested key elements of this model in the bumblebee Bombus terrestris. In colonies from which queens were sequentially removed, queen tenure was significantly negatively associated with worker male production, confirming that workers gain direct fitness by usurping the queen. In unmanipulated colonies, queen fecundity decreased significantly over the latter part of the colony cycle, confirming that workers’ indirect fitness from maintaining queens declines over time. Finally, in an experiment simulating loss of queen fecundity by removal of queens’ eggs, worker-to-queen aggression increased significantly and aggressive workers were significantly more likely to become egg layers, consistent with workers monitoring queen fecundity to assess the net benefit of future reproduction. Overall, by upholding key assumptions and predictions of the model, our results provide novel empirical support for kin-selected conflict over resource inheritance.

Genetic bottlenecks can limit the success of populations colonizing new ranges. However, successful colonizations can occur despite bottlenecks, a phenomenon known as the genetic paradox of invasion. Eusocial Hymenoptera such as bumblebees ( Bombus spp.) should be particularly vulnerable to genetic bottlenecks, since homozygosity at the sex-determining locus leads to costly diploid male production (DMP). The Tree Bumblebee ( Bombus hypnorum ) has rapidly colonized the UK since 2001 and has been highlighted as exemplifying the genetic paradox of invasion. Using microsatellite genotyping, combined with the first genetic estimates of DMP in UK B. hypnorum , we tested two alternative genetic hypotheses (‘bottleneck’ and ‘gene flow’ hypotheses) for B. hypnorum 's colonization of the UK. We found that the UK population has not undergone a recent severe genetic bottleneck and exhibits levels of genetic diversity falling between those of widespread and range-restricted Bombus species. Diploid males occurred in 15.4% of reared colonies, leading to an estimate of 21.5 alleles at the sex-determining locus. Overall, the findings show that this population is not bottlenecked, instead suggesting that it is experiencing continued gene flow from the continental European source population with only moderate loss of genetic diversity, and does not exemplify the genetic paradox of invasion.

Genetic bottlenecks can limit the success of populations colonizing new ranges. However, successful colonizations can occur despite bottlenecks, a phenomenon known as the genetic paradox of invasion. Eusocial Hymenoptera such as bumblebees (Bombus spp.) should be particularly vulnerable to genetic bottlenecks, since homozygosity at the sex-determining locus leads to costly diploid male production (DMP). The Tree Bumblebee (Bombus hypnorum) has rapidly colonized the UK since 2001 and has been highlighted as exemplifying the genetic paradox of invasion. Using microsatellite genotyping, combined with the first genetic estimates of DMP in UK B. hypnorum, we tested two alternative genetic hypotheses (‘bottleneck’ and ‘gene flow’ hypotheses) for B. hypnorum’s colonization of the UK. We found that the UK population has not undergone a recent severe genetic bottleneck and exhibits levels of genetic diversity falling between those of widespread and range-restricted Bombus species. Diploid males occurred in 15.4% of reared colonies, leading to an estimate of 21.5 alleles at the sex-determining locus. Overall, the findings show that this population is not bottlenecked, instead suggesting that it is experiencing continued gene flow from the continental European source population with only moderate loss of genetic diversity, and does not exemplify the genetic paradox of invasion.

Anti-retroviral therapy (ART) regimes for HIV are associated with raised levels of circulating triglycerides (TG) in western populations. However, there are limited data on the impact of ART on cardiometabolic risk in sub-Saharan African (SSA) populations. Pooled analyses of 14 studies comprising 21 023 individuals, on whom relevant cardiometabolic risk factors (including TG), HIV and ART status were assessed between 2003 and 2014, in SSA. The association between ART and raised TG (>2.3 mmol/L) was analysed using regression models. Among 10 615 individuals, ART was associated with a two-fold higher probability of raised TG (RR 2.05, 95% CI 1.51-2.77, I =45.2%). The associations between ART and raised blood pressure, glucose, HbA1c, and other lipids were inconsistent across studies. Evidence from this study confirms the association of ART with raised TG in SSA populations. Given the possible causal effect of raised TG on cardiovascular disease (CVD), the evidence highlights the need for prospective studies to clarify the impact of long term ART on CVD outcomes in SSA.