315 research outputs found

    Large-scale migration synchrony between parasitoids and their host

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    1. Parasitoids are a valuable group for conservation biological control. In their role as regulators of aphid pests, it is critical that their lifecycle is synchronised with their hosts in both space and time. This is because a synchronised parasitoid community is more likely to strengthen the overall conservation biological control effect, thus damping aphid numbers and preventing potential outbreaks. One component of this host-parasitoid system was examined, that of migration, and the hypothesis that peak summer parasitoid and host migrations are synchronised in time was tested. 2. Sitobion avenae Fabricius and six associated parasitoids were sampled from 1976 to 2013 using 12.2-m suction-traps from two sites in Southern England. The relationship between peak weekly S. avenae counts and their parasitoids was quantified. 3. Simple regression models showed that the response of the peak parasitoids to the host was positive: generally, more parasitoids migrated with increasing numbers of aphids. Further, when averaged over time, the parasitoid migration peak date corresponded with the aphid migration peak. The co-occurrence of the peaks was between 51% and 64%. However, the summer peak in aphid migration is not steadily shifting forward with time unlike spring first flights of aphids. Cross-correlation analysis showed that there were no between-year lagged effects of aphids on parasitoids. 4. These results demonstrate that the peak in migration phenology between host and parasitoid is broadly synchronised within a season. Because the threshold temperature for flight (>12 degrees C) was almost always exceeded in summer, the synchronising agent is likely to be crop senescence, not temperature. Studies are needed to assess the effects of climate change on the mismatch potential between parasitoids and their hosts

    Are insects declining and at what rate? An analysis of standardised, systematic catches of aphid and moth abundances across Great Britain

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    1. Although we have known anecdotally that insects have been declining in Great Britain for more than 100 years, insect declines have only been statistically estimated over the last 20 years. Estimation of the rate of those declines is still hotly debated,fuelled by a lack of standardised, systematically collected data. 2. More than 24 million individual moths and aphids collected from 112 light traps and 25 12.2 m suction-traps, respectively, were analysed using mixed models. Our objective was to estimate the long-term trends in both groups based on annual totals recorded every year between 1969 and 2016. 3. The models showed that two paradigms existed: Over 47 years, long-term linear trends showed that moths had declined significantly by −31%, but short-term trends indicated that there were periods of significant decline and recovery in most decades since the 1960s. Conversely, despite aphid annual totals fluctuating widely, this group was in a steady state over the long-term, with a non-significant decline of −7.6%. Sensitivity analysis revealed that moth trends were not driven by a group of abundant species, but the sign of the overall aphid trends may have been driven by three of the most abundant species. 4. The spatial extent of moth trends suggests that they are extremely heterogeneous.Uniquely, moth declines were different among several habitat types, with robust significant declines found in coastal, urban and woodland habitats, but notably not in agricultural,parkland and scrubland habitats. Conversely, aphid trends showed spatial synchrony extending to 338 km, albeit with local variation

    The effect of dairy cow breed on milk production, cow traffic and milking characteristics in a pasture-based automatic milking system

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    peer-reviewedDespite the increasing frequency of integrated automatic milking (AM) and pasture-based systems, there is limited knowledge available on the suitability of different dairy cow breeds to these systems. Thus, the objective of this experiment was to establish the performance of three breeds in a pasture-based AM system with respect to milk production, cow traffic and milking characteristics. The breeds examined were Holstein Friesian (HF), Jersey x HF (JEX) and Norwegian Red x HF (NRX), all of which have been previously identified as being compatible with conventional milking pasture-based systems. The experiment was conducted in mid-lactation and variables measured included milking frequency, -interval, -outcome and -characteristics, milk yield/milking and per day, wait time/visit and per day, return time/visit and the daily distribution of milking events. Data were statistically analysed using least squares means mixed procedure models, while the proportion of different milking events were analysed using the logistics procedure. While there were no significant differences between breeds for milking frequency, or milk production, significant differences did exist for proportion of successful and failed milkings events, with NRX cows recording the highest and lowest proportions, respectively. JEX also recorded a significantly shorter dead time/quarter at 17.6 s/milking compared to the HF and NRX breeds at 28.5 and 27.7 s/milking, respectively. Significant differences also existed with regard to cow traffic, with the NRX breed returning from pasture more quickly and waiting a shorter time both per visit and per day in the pre-milking yard. The distribution of milking events differed between the breeds examined, with the JEX cows recording less milkings in the hour after the pre-selection gate changes of 0000 h and 1600 h. JEX also recorded a significantly greater proportion of milkings than the NRX and HF cows during the hours at which the lowest proportion of total milking events were recorded (0400–0600 h). For the optimisation of the AM system it is important to have an even distribution of milkings throughout the day. Based on the evidence from the current experiment, this may be best achieved by a mixed breed herd rather than a single breed herd. However, the performance of the examined breeds should also be analysed in the context of the whole AM farm system, over an entire lactation, taking into consideration the range of variables that contribute to a profitable farm system

    Bucking the trend: the diversity of Anthropocene ‘winners’ among British moths

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    An appreciation of how some species are becoming more common despite unprecedented anthropogenic pressures could offer key insights for mitigating the global biodiversity crisis.  Research to date has largely focused on declining species, while species that are becoming more common have received relatively little attention. Macro-moths in Great Britain are well-studied and species-rich, making them an ideal group for addressing this knowledge gap. Here, we examine changes in 51 successful species between 1968 and 2016 using 4.5 million occurrence records and a systematic monitoring dataset. We employ 3D graphical analysis to visualise long-term multidimensional trends in prevalence (abundance and range) and use vector autoregression models to test whether past values of local abundance are useful for predicting changes in the extent of occurrence. The responses of Anthropocene winners are heterogeneous, suggesting multiple drivers are responsible. Changes in range and local abundance frequently occur intermittently through time, demonstrating the value of long-term, continuous monitoring. There is significant diversity among the winners themselves, which include widespread generalists, habitat specialists, and recent colonists. We offer brief discussion of possible causal factors and the wider ecosystem implications of these trends

    Long‐term trends in migrating Brassicogethes aeneus in the UK

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    BACKGROUND The pollen beetle (Brassicogethes aeneus) causes significant yield loss in oilseed rape (Brassica napus). Predicting population changes remains a scientific challenge, especially since its phenology and abundance varies dramatically over space and time. We used generalized additive models to investigate the long-term trends in pollen beetle annual, seasonal and monthly counts from Rothamsted 12.2 m suction-traps. We hypothesised that the beetle's abundance is positively related to the area of oilseed rape at a national and regional level. We used random forest models to investigate the inter-generational relationship within years. RESULTS Although B. aeneus annual counts and area of oilseed rape grown in the UK both increased by 162% and 113%, respectively, over the time period, they were not significantly related. The size of the immigrating pollen beetle population (up to June 1st) can be explained both by the size of the population in the previous summer and prevailing winter temperatures, indicating a positive feedback mechanism. CONCLUSION Currently, pollen beetle numbers continue to increase in the UK, meaning that control issues may persist, however the relationship between counts in spring, during the susceptible phase of the crop, and counts in the previous summer indicates that it may be possible to forecast the counts of the spring migration of B. aeneus a few months in advance using suction-trap samples, which could aid decisions on control options

    The Performance Effect of Scheduled Carbohydrate and Caffeine Intake during Simulated Team Sport Match-Play

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    The aim of the current investigation was to identify the effects of scheduled carbohydrate (CHO) and caffeine (CAF) supplementation on simulated team sport match-play performance. Ten male hurling players completed three hurling match-play simulation protocols (HSP) performed 7 days apart in a double-blind, randomized design. Supplementation included CHO, CHO + CAF, and placebo (PLA). In a randomized order, participants ingested either a 6% CHO solution, a PLA solution of similar taste, or a combined intake of 6% CHO solution + 200 mg CAF capsule. At specific time points (Pre-0 min; half time (HT)-30 min; full time (FT)-60 min), participants completed a repeated sprint protocol (RAST; 12 7 20 m). Physiological [% maximal oxygen uptake (%VO2max), % mean oxygen uptake (%VO2mean), % maximal heart rate (%HRmax), % mean heart rate (%HRmean), respiratory exchange ratio (RER), and blood lactate (BLa)] and performance [(best sprint time (RSAbest), mean sprint time (RSAmean), and rate of perceived exertion (RPE)] variables were monitored throughout each simulation. Non-significant differences were observed between supplement trials (CHO, CHO + CAF, and PLA) for BLa (\u3b72 = 0.001, small), %VO2max (\u3b72 = 0.001, small), %VO2mean (\u3b72 = 0.004, small), %HRmax (\u3b72 = 0.007, small), %HRmean (\u3b72 = 0.018, small), RER (\u3b72 = 0.007, small), RPE (\u3b72 = 0.007, small), and RSAbest (\u3b72 = 0.050, small). RSAmean performance significantly improved in CHO + CAF trials compared to PLA, with sprint times significantly improved from Pre to FT also (\u3b72 = 0.135, medium). A significant difference was observed in BLa between time points (Pre, HT, and FT) (\u3b72 = 0.884, large) in % HRmax (\u3b72 = 0.202, medium), %HRmean (\u3b72 = 0.477, large), and RER (\u3b72 = 0.554, large) across halves and in RPE across time points (\u3b72 = 0.670, large). Our data provide novel data regarding the effects of CHO and CAF supplementation on team sport performance, with co-ingestion of CHO + CAF reducing the decrement in repeated sprint performance compared to PLA

    The effect of concentrate supplementation on milk production and cow traffic in early and late lactation in a pasture-based automatic milking system

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    peer-reviewedThe objective of this experiment was to establish the effect of low-concentrate (LC) and high-concentrate (HC) supplementation in the early and late periods of lactation on milk production and cow traffic in a pasture-based automatic milking (AM) system. In total, 40 cows (10 primiparous and 30 multiparous) were randomly assigned to one of the two treatments. The experimental periods for the early and late lactation trials extended from 23 February to 12 April 2015 and 31 August to 18 October 2015, respectively (49 days in each trial period). The early lactation supplement levels were 2.3 and 4.4 kg/cow per day for LC and HC, respectively, whereas the late lactation supplement levels were 0.5 and 2.7 kg/cow per day for LC and HC, respectively. Variables measured included milking frequency, milking interval, milking outcome and milking characteristics, milk yield/visit and per day, wait time/visit and per day, return time/visit and the distribution of gate passes. As the herd was seasonal (spring) calving, the experimental periods could not run concurrently and as a result no statistical comparison between the periods was conducted. There was no significant effect of treatment in the early lactation period on any of the milk production, milking characteristics or cow traffic variables. However, treatment did significantly affect the distribution of gate passes, with the HC cows recording significantly more gate passes in the hours preceding the gate time change such as hours 7 (P<0.01), 15 (P<0.05), 20, 21 (P<0.001), and 22 (P<0.05), whereas the LC treatment recorded significantly more gate passes in the hours succeeding the gate time change, such as time points 2 (P<0.01) and 10 (P<0.05). There was a significant effect of treatment in late lactation, with HC having a greater milk yield (P<0.01), milking duration and activity/day (P<0.05), while also having a significantly shorter milking interval (P<0.05) and return time/visit (P<0.01). The distribution of gate passes were similar to the early lactation period, with HC also recording a significantly greater number of gate passes during the early morning period (P<0.01) when visitations were at their lowest. Any decision regarding the supplementing of dairy cows with concentrates needs to be examined from an economic perspective, to establish if the milk production and cow traffic benefits displayed in late lactation outweigh the cost of the concentrate; thereby ensuring that the decision to supplement is financially prudent

    The long-term population dynamics of common wasps in their native and invaded range

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    Summary 1. Populations of introduced species are often thought to perform differently, or experience different population dynamics, in their introduced range compared to their native habitat. Differences between habitats in climate, competition or natural enemies may result in populations with varying density dependence and population dynamics. 2. We examined the long‐term population dynamics of the invasive common wasp, Vespula vulgaris, in its native range in England and its invaded range in New Zealand. We used 39 years of wasp density data from four sites in England, and 23 years of data from six sites in New Zealand. Wasp population time series was examined using partial rate correlation functions. Gompertz population models and multivariate autoregressive state‐space (MARSS) models were fitted, incorporating climatic variation. 3. Gompertz models successfully explained 59–66% of the variation in wasp abundance between years. Density dependence in wasp populations appeared to act similarly in both the native and invaded range, with wasp abundance in the previous year as the most important variable in predicting intrinsic rate of increase (r). No evidence of cyclic population dynamics was observed. 4. Both the Gompertz and MARSS models highlighted the role of weather conditions in each country as significant predictors of annual wasp abundance. The temporal evolution of wasp populations at all sites was best modelled jointly using a single latent dynamic factor for local trends, with the inclusion of a latent spring weather covariate. That same parsimonious multivariate model structure was optimal in both the native and invaded range. 5. Density dependence is overwhelmingly important in predicting wasp densities and ‘wasp years’ in both the native and invaded range. Spring weather conditions in both countries have a major influence, probably through their impact on wasp colony initiation and early development. The population dynamics in the native range and invaded range show no evidence of cyclic boom‐and‐bust dynamics. Invasive species may not exhibit different population dynamics despite considerable variation in abundances throughout their distribution

    Time to go global: a consultation on global health competencies for postgraduate doctors

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    BACKGROUND: Globalisation is having profound impacts on health and healthcare. We solicited the views of a wide range of stakeholders in order to develop core global health competencies for postgraduate doctors. METHODS: Published literature and existing curricula informed writing of seven global health competencies for consultation. A modified policy Delphi involved an online survey and face-to-face and telephone interviews over three rounds. RESULTS: Over 250 stakeholders participated, including doctors, other health professionals, policymakers and members of the public from all continents of the world. Participants indicated that global health competence is essential for postgraduate doctors and other health professionals. Concerns were expressed about overburdening curricula and identifying what is 'essential' for whom. Conflicting perspectives emerged about the importance and relevance of different global health topics. Five core competencies were developed: (1) diversity, human rights and ethics; (2) environmental, social and economic determinants of health; (3) global epidemiology; (4) global health governance; and (5) health systems and health professionals. CONCLUSIONS: Global health can bring important perspectives to postgraduate curricula, enhancing the ability of doctors to provide quality care. These global health competencies require tailoring to meet different trainees' needs and facilitate their incorporation into curricula. Healthcare and global health are ever-changing; therefore, the competencies will need to be regularly reviewed and updated

    Investment appraisal of automatic milking and conventional milking technologies in a pasture-based dairy system

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    peer-reviewedThe successful integration of automatic milking (AM) systems and grazing has resulted in AM becoming a feasible alternative to conventional milking (CM) in pasture-based systems. The objective of this study was to identify the profitability of AM in a pasture-based system, relative to CM herringbone parlors with 2 different levels of automation, across 2 farm sizes, over a 10-yr period following initial investment. The scenarios which were evaluated were (1) a medium farm milking 70 cows twice daily, with 1 AM unit, a 12-unit CM medium-specification (MS) parlor and a 12-unit CM high-specification (HS) parlor, and (2) a large farm milking 140 cows twice daily with 2 AM units, a 20-unit CM MS parlor and a 20-unit CM HS parlor. A stochastic whole-farm budgetary simulation model combined capital investment costs and annual labor and maintenance costs for each investment scenario, with each scenario evaluated using multiple financial metrics, such as annual net profit, annual net cash flow, total discounted net profitability, total discounted net cash flow, and return on investment. The capital required for each investment was financed from borrowings at an interest rate of 5% and repaid over 10-yr, whereas milking equipment and building infrastructure were depreciated over 10 and 20 yr, respectively. A supporting labor audit (conducted on both AM and CM farms) showed a 36% reduction in labor demand associated with AM. However, despite this reduction in labor, MS CM technologies consistently achieved greater profitability, irrespective of farm size. The AM system achieved intermediate profitability at medium farm size; it was 0.5% less profitable than HS technology at the large farm size. The difference in profitability was greatest in the years after the initial investment. This study indicated that although milking with AM was less profitable than MS technologies, it was competitive when compared with a CM parlor of similar technology
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