1,660 research outputs found

    Courgette Production: Pollination Demand, Supply, and Value

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    This is the final version of the article. Available from OUP via the DOI in this record.Courgette (Cucurbita pepo L.) production in the United Kingdom is estimated to be worth £6.7 million. However, little is known about this crop’s requirement for insect-mediated pollination (pollinator dependence) and if pollinator populations in a landscape are able to fulfil its pollination needs (pollination deficit). Consequently, pollination experiments were conducted over 2 yr to explore pollinator dependence and pollination deficit in field-grown courgette in the United Kingdom. Results showed that pollination increased yield by 39% and there was no evidence of pollination limitation on crop yield. This was evidenced by a surprisingly low pollination deficit (of just 3%) and no statistical difference in yield (length grown, circumference, and weight) between open- and hand-pollinated crops. Nonetheless, the high economic value of courgettes means that reducing even the small pollination deficit could still increase profit by ∼£166/ha. Interestingly, 56% of fruit was able to reach marketable size and shape without any pollination. Understanding a crop’s requirement for pollinators can aid growers in their decision-making about what varieties and sites should be used. In doing so, they may increase their agricultural resilience and further their economic advantage.This work was funded as part of PhD studentship (CP118) sponsored by the Agriculture and Horticulture Development Board, United Kingdom. J.O. was also supported by a grant from the Natural Environment Research Council United Kingdom [NE/J014893/1]

    ACVIM Small Animal Consensus Recommendations on the Treatment and Prevention of Uroliths in Dogs and Cats.

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    In an age of advancing endoscopic and lithotripsy technologies, the management of urolithiasis poses a unique opportunity to advance compassionate veterinary care, not only for patients with urolithiasis but for those with other urinary diseases as well. The following are consensus-derived, research and experience-supported, patient-centered recommendations for the treatment and prevention of uroliths in dogs and cats utilizing contemporary strategies. Ultimately, we hope that these recommendations will serve as a foundation for ongoing and future clinical research and inspiration for innovative problem solving

    Effects of an agri-environment scheme on bumblebee reproduction at local and landscape scales

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    Agri-environment schemes (AES) have been implemented across Europe, aiming to mitigate effects of habitat loss in agro-ecosystems for a range of declining species. These include pollinating insects such as bumblebees, for which positive effects of AES on abundance and species richness have been shown. However, there is a lack of evidence for effects of AES on reproduction of target species, at either local or landscape scales. We conducted a large-scale study across landscapes exhibiting a gradient of agricultural intensity to investigate the effects of a targeted flower mixture, sown in patches of three different sizes, on an index of the total biomass of bumblebee sexuals (males and queens) on replicated transects within each landscape. We used this index (MQ) as a measure of bumblebee reproduction. After controlling for floral density on transects, we found that MQ was significantly higher on sown flower patches than on conventionally managed control patches at local scales throughout the three-year study. While sown flower patches did not significantly increase MQ in surrounding landscapes, MQ was higher in landscapes surrounding larger (1. ha) than smaller (0.25. ha) sown patches. Our results suggest that, while responses of different bee species may vary depending on the plant species sown, targeted flower mixtures can enhance bumblebee reproduction by providing locally attractive forage resources to bumblebees of all castes and sexes from nests within foraging distance. If established at large enough scales, sown flower patches may lead to a detectable spill-over of reproductives into surrounding landscapes. Furthermore, effects of sown patches on MQ were moderated by landscape context, the strongest positive responses being detected at sites with high proportions of arable land. This supports previous findings that AES can deliver greater net benefits for pollinators in more intensively farmed landscapes.This research was funded by the UK Department for Environment, Food and Rural Affairs (research grant BD1625), and Natural England, Peterborough, UK

    Modelling effects of honeybee behaviors on the distribution of pesticide in nectar within a hive and resultant in-hive exposure

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    This is the author accepted manuscript. The final version is available from the American Chemical Society via the DOI in this record.Recently, the causes of honeybee colony losses have been intensely studied, showing that there are multiple stressors implicated in colony declines, one stressor being the exposure to pesticides. Measuring exposure of individual bees within a hive to pesticide is at least as difficult as assessing the potential exposure of foraging bees to pesticide. We present a model to explore how heterogeneity of pesticide distribution on a comb in the hive can be driven by worker behaviors. The model contains simplified behaviors to capture the extremes of possible heterogeneity of pesticide location/deposition within the hive to compare with exposure levels estimated by averaging values across the comb. When adults feed on nectar containing the average concentration of all pesticide brought into the hive on that particular day it is likely representative of the worst case exposure scenario. However, for larvae, clustering of pesticide in the comb can lead to higher exposure levels than taking an average concentration in some circumstances. The potential for extrapolating the model to risk assessment is discussed.J.R. was funded to do this work on an Industrial CASE PhD studentship funded by the Biology and Biotechnology Sciences Research Council of the UK (BBSRC), and Syngenta. J.O. and M.B. were supported on BBSRC project BB/K014463/1

    Oilseed rape (Brassica napus) as a resource for farmland insect pollinators: quantifying floral traits in conventional varieties and breeding systems

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    This is the final version of the article. Available from the publisher via the DOI in this record.Oilseed rape (OSR; Brassica napus L.) is a major crop in temperate regions and provides an important source ofnutrition to many of the yield-enhancing insect flower visitors that consume floral nectar. The manipulation ofmechanisms that control various crop plant traits for the benefit of pollinators has been suggested in the bid toincrease food security, but little is known about inherent floral trait expression in contemporary OSR varieties orthe breeding systems used in OSR breeding programmes. We studied a range of floral traits in glasshouse-grown, certified conventional varieties of winter OSR to test for variation among and within breeding systems.We measured 24-h nectar secretion rate, amount, concentration and ratio of nectar sugars per flower, and sizesand number of flowers produced per plant from 24 varieties of OSR representing open-pollinated (OP), genicmale sterility (GMS) hybrid and cytoplasmic male sterility (CMS) hybrid breeding systems. Sugar concentrationwas consistent among and within the breeding systems; however, GMS hybrids produced more nectar and moresugar per flower than CMS hybrid or OP varieties. With the exception of ratio of fructose/glucose in OP vari-eties, we found that nectar traits were consistent within all the breeding systems. When scaled, GMS hybridsproduced 1.73 times more nectar resource per plant than OP varieties. Nectar production and amount of nectarsugar in OSR plants were independent of number and size of flowers. Our data show that floral traits of glass-house-grown OSR differed among breeding systems, suggesting that manipulation and enhancement of nectarrewards for insect flower visitors, including pollinators, could be included in future OSR breeding programmes.This work was fundedby the BBSRC, including support from an Insect Pollinators Ini-tiative grant awarded to GAW (BB/I000968/1) that was jointlyfunded by the BBSRC, NERC, the Wellcome Trust, Defra, andthe Scottish Government. Support was also received from HighWycombe Beekeepers’ Association. Rothamsted Researchreceives strategic funding from the Biotechnology and BiologicalSciences Research Council (BBSRC) of the UK

    Multiple stressors: using the honeybee model BEEHAVE to explore how spatial and temporal forage stress affects colony resilience

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    The causes underlying the increased mortality of honeybee colonies (Apis mellifera) observed over the past decade remain unclear. Since so far the evidence for monocausal explanations is equivocal, involvement of multiple stressors is generally assumed. We here focus on various aspects of forage availability, which have received less attention than other stressors because it is virtually impossible to explore them empirically. We applied the colony model BEEHAVE, which links within-hive dynamics and foraging, to stylized landscape settings to explore how foraging distance, forage supply, and “forage gaps”, i.e. periods in which honeybees cannot find any nectar and pollen, affect colony resilience and the mechanisms behind. We found that colony extinction was mainly driven by foraging distance, but the timing of forage gaps had strongest effects on time to extinction. Sensitivity to forage gaps of 15 days was highest in June or July even if otherwise forage availability was sufficient to survive. Forage availability affected colonies via cascading effects on queen's egg-laying rate, reduction of new-emerging brood stages developing into adult workers, pollen debt, lack of workforce for nursing, and reduced foraging activity. Forage gaps in July led to reduction in egg-laying and increased mortality of brood stages at a time when the queen's seasonal egg-laying rate is at its maximum, leading to colony failure over time. Our results demonstrate that badly timed forage gaps interacting with poor overall forage supply reduce honeybee colony resilience. Existing regulation mechanisms which in principle enable colonies to cope with varying forage supply in a given landscape and year, such as a reduction in egg-laying, have only a certain capacity. Our results are hypothetical, as they are obtained from simplified landscape settings, but they are consistent with existing empirical knowledge. They offer ample opportunities for testing the predicted effects of forage stress in controlled experiments

    REVIEW: Towards a systems approach for understanding honeybee decline: a stocktaking and synthesis of existing models

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    Published© 2013 The Authors. Journal of Applied Ecology © 2013 British Ecological Society This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Summary 1. The health of managed and wild honeybee colonies appears to have declined substantially in Europe and the United States over the last decade. Sustainability of honeybee colonies is important not only for honey production, but also for pollination of crops and wild plants alongside other insect pollinators. A combination of causal factors, including parasites, pathogens, land use changes and pesticide usage, are cited as responsible for the increased colony mortality. 2. However, despite detailed knowledge of the behaviour of honeybees and their colonies, there are no suitable tools to explore the resilience mechanisms of this complex system under stress. Empirically testing all combinations of stressors in a systematic fashion is not feasible. We therefore suggest a cross-level systems approach, based on mechanistic modelling, to investigate the impacts of (and interactions between) colony and land management. 3. We review existing honeybee models that are relevant to examining the effects of different stressors on colony growth and survival. Most of these models describe honeybee colony dynamics, foraging behaviour or honeybee – varroa mite – virus interactions. 4. We found that many, but not all, processes within honeybee colonies, epidemiology and foraging are well understood and described in the models, but there is no model that couples in-hive dynamics and pathology with foraging dynamics in realistic landscapes. 5. Synthesis and applications. We describe how a new integrated model could be built to simulate multifactorial impacts on the honeybee colony system, using building blocks from the reviewed models. The development of such a tool would not only highlight empirical research priorities but also provide an important forecasting tool for policy makers and beekeepers, and we list examples of relevant applications to bee disease and landscape management decisions.Biotechnology and Biological Sciences Research Council (BBSRC

    Identification of secretory granule phosphatidylinositol 4,5-bisphosphateinteracting proteins using an affinity pulldown strategy

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    Phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P-2) synthesis is required for calcium-dependent exocytosis in neurosecretory cells. We developed a PtdIns(4,5)P-2 bead pulldown strategy combined with subcellular fractionation to identify endogenous chromaffin granule proteins that interact with PtdIns(4,5)P-2. We identified two synaptotagmin isoforms, synaptotagmins 1 and 7; spectrin; alpha-adaptin; and synaptotagmin-like protein 4 (granuphilin) by mass spectrometry and Western blotting. The interaction between synaptotagmin 7 and PtdIns(4,5)P-2 and its functional relevance was investigated. The 45-kDa isoform of synaptotagmin 7 was found to be highly expressed in adrenal chromaffin cells compared with PC12 cells and to mainly localize to secretory granules by subcellular fractionation, immunoisolation, and immunocytochemistry. We demonstrated that synaptotagmin 7 binds PtdIns(4,5)P-2 via the C2B domain in the absence of calcium and via both the C2A and C2B domains in the presence of calcium. We mutated the polylysine stretch in synaptotagmin 7 C2B and demonstrated that this mutant domain lacks the calcium-independent PtdIns(4,5)P-2 binding. Synaptotagmin 7 C2B domain inhibited catecholamine release from digitonin-permeabilized chromaffin cells, and this inhibition was abrogated with the C2B polylysine mutant. These data indicate that synaptotagmin 7 C2B-effector interactions, which occur via the polylysine stretch, including calcium-independent PtdIns(4,5)P-2 binding, are important for chromaffin granule exocytosis

    Searching for nests of the invasive Asian hornet (Vespa velutina) using radio-telemetry

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    This is the final version of the article. Available from the publisher via the DOI in this recordAsian hornets (Vespa velutina) are voracious predators of bees, and are the latest emerging threat to managed and wild pollinator populations in Europe. To prevent establishment or reduce the rate of spread of V. velutina, early detection and destruction of nests is considered the only option. Detection is difficult as their nests are well hidden and flying hornets are difficult to follow over long distances. We address this challenge by tracking individual V. velutina workers flying back to their nests using radio telemetry for the first time, finding five previously undiscovered nests, up to 1.33 km from hornet release points. Hornets can fly with 0.28 g tags if the tag:hornet ratio is less than 0.8. This method offers a step-change in options to tackle the spread of this invader, providing an efficient means of finding V. velutina nests in complex environments to manage this emerging threat to pollinators.We thank Olivier Bonnard for discussions, sourcing materials, and advice on locating foraging V. velutina workers at INRA Bordeaux-Aquitaine. We also thank members of Jersey Beekeeping Association for their assistance in catching V. velutina workers in Jersey. The work was funded by a Defra research project grant (PH0532), with additional support by the States of Jersey Department of Environment and generous philanthropic donations by the South West Beekeeping Associations’ Forum (SWBKF), Somerset Beekeeping Association, Dorset Beekeeping Association, Cornwall Beekeeping Association, West Cornwall Beekeeping Association, Devon Beekeeping Association, Bournemouth & South Dorset Beekeeping Association, and B.J. Sherriff. We are grateful to INRA Bordeaux-Aquitaine, States of Jersey Department of Environment, and Durrell Wildlife Park for their welcome and permission to use facilities at their institutions

    A review of the success of the UK strategy to tackle the invasive insect Vespa velutina nigrithorax, the “Asian hornet”

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    Interreg Atlantic Area project: Atlantic Positive – Conservation of Atlantic Pollination services and control of the invasive species Vespa velutina. Work-package 8; Action No. 1: Strategy to prevent the spread of V. velutina to the UK. To prevent Vespa velutina from spreading across the British mainland, avoiding economic loss and harm to biodiversity, this report describes action plans and specific measures for the British mainland and the maritime space between UK and mainland Europe.The UK’s strategy to prevent the establishment of the Asian hornet, Vespa velutina nigrithorax, and/or manage its presence and impacts is embedded within the UK’s generic strategy for invasive non-native species, but specifically informed by the non-native species risk assessment for Vespa velutina and the pest-specific contingency plan for the Asian hornet. This report introduces relevant UK policies and legislation for invasive non-native species, before summarising the UK’s assessment of risk of entry, establishment and impact, and its rapid response plans addressing the Asian hornet’s periodic incursions in the UK. The report describes the effectiveness of those plans to manage and control the spread of the Asian hornet on the British mainland over the last seven years; and provides a reflection on the next steps required to ensure establishment is delayed as long as possible, while preparing for a time when the species may become established in the UK. The details may provide useful pointers for other European countries in which the Asian hornet is not yet established, but also incorporates suggestions for the UK based on actions from regions where the hornet has already become established.European Regional Development Fund (ERDF) Interreg Atlantic Area ProgrammeBiotechnology and Biological Sciences Research Council (BBSRC
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