scholarly journals Combined Effects of Pesticides and Electromagnetic-Fields on Honeybees: Multi-Stress Exposure

Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 716
Author(s):  
Daniela Lupi ◽  
Marco Palamara Mesiano ◽  
Agnese Adani ◽  
Roberto Benocci ◽  
Roberto Giacchini ◽  
...  
Keyword(s):  
Electromagnetic Fields ◽  
Biodiversity Loss ◽  
Stress Conditions ◽  
Combined Effects ◽  
Behavioral Alterations ◽  
Pollinator Decline ◽  
Electric Line ◽  
Pesticide Stress ◽  
Bee Colony ◽  
Colony Survival

Honeybee and general pollinator decline is extensively reported in many countries, adding new concern to the general biodiversity loss. Many studies were addressed to assess the causes of pollinator decline, concluding that in most cases multi-stress effects were the most probable ones. In this research, the combined effects of two possible stress sources for bees, pesticides and electromagnetic fields (multi-stress conditions), were analyzed in the field. Three experimental sites were chosen: a control one far from direct anthropogenic stress sources, a pesticide-stress site and multi-stress one, adding to the same exposure to pesticides the presence of an electromagnetic field, coming from a high-voltage electric line. Experimental apiaries were monitored weekly for one year (from April 2017 to April 2018) by means of colony survival, queen activity, storage and brood amount, parasites and pathogens, and several biomarkers in young workers and pupae. Both exposure and effect biomarkers were analysed: among the first, acetylcholinesterase (AChE), catalase (CAT), glutathione S-transferase (GST) and alkaline phosphatase (ALP) and Reactive Oxygen Species (ROS); and among the last, DNA fragmentation (DNAFRAGM) and lipid peroxidation (LPO). Results showed that bee health conditions were the worst in the multi-stress site with only one colony alive out of the four ones present at the beginning. In this site, a complex picture of adverse effects was observed, such as disease appearance (American foulbrood), higher mortality in the underbaskets (common to pesticide-stress site), behavioral alterations (queen changes, excess of honey storage) and biochemical anomalies (higher ALP activity at the end of the season). The overall results clearly indicate that the multi-stress conditions were able to induce biochemical, physiological and behavioral alterations which severely threatened bee colony survival.

scholarly journals Melliferous Potential of Weedy Herbaceous Plants in Crop Fields of Romania from 1949 to 2012

2018 ◽  
Vol 62 (2) ◽  
pp. 149-165 ◽  
Author(s):  
Nicoleta Ion ◽  
Jean-François Odoux ◽  
Bernard E. Vaissière
Keyword(s):  
Plant Species ◽  
Agricultural Practices ◽  
Farming Systems ◽  
Nectar Production ◽  
Crop Fields ◽  
Bee Colony ◽  
Intensive Farming ◽  
Flowering Season ◽  
Companion Plants ◽  
Colony Survival

Abstract Intensive farming systems have led to reduced food availability for honey bees which could be related to their current decline. A global tool is needed in order to assess the melliferous potential of plant species that could be developed as crops or companion plants in such systems. This review is based upon a survey from an extensive dataset collected in Romania over the last sixty years to record the nectar production of 153 weedy species. While there was considerable variation among these plants, we found that the melliferous potential of such large families as the Brassicaceae was low, that of the Apiaceae, Asteraceae and Fabaceae at an intermediate level, and that of the Lamiaceae and Boraginaceae the highest. High nectariferous potential was found to be an important feature of perennial ruderal species. Within the main flowering season, perennials provided much more nectar than annuals. These results could help to develop new agricultural practices more compatible with honey bee colony survival and honey production, as some of these plant species could provide a solution to enable agriculture and beekeeping to coexist in a sustainable way.

scholarly journals Prioritising sites for pollinators in a fragmented coastal nectar habitat network in Western Europe

2019 ◽  
Vol 34 (12) ◽  
pp. 2791-2805
Author(s):  
George B. Paterson ◽  
Gill Smart ◽  
Paul McKenzie ◽  
Sally Cook
Keyword(s):  
Western Europe ◽  
Phase 1 ◽  
Biodiversity Loss ◽  
Habitat Connectivity ◽  
Conservation Strategies ◽  
Pollinator Decline ◽  
Efficient Manner ◽  
Spatial Metrics ◽  
Habitat Network ◽  
Habitat Patches

Abstract Context Habitat loss and fragmentation contribute significantly to pollinator decline and biodiversity loss globally. Conserving high quality habitats whilst restoring and connecting remnant habitat is critical to halt such declines. Objectives We quantified the connectivity of pollinator habitats for a generic focal species (GFS) which represented three groups of pollinators in an existing coastal nectar habitat network. Subsequently, in partnership with a conservation agency, we modelled an improved landscape that identified priority habitat patches to increase connectivity for pollinators. Methods We selected 4260 pollinator habitats along an 80 km section of coastland in Scotland using Phase 1 habitat data. A GFS represented three vulnerable European pollinator groups while graph theory and spatial metrics were used to identify optimal sites that could enhance habitat connectivity. Results Higher dispersing species experienced greater habitat connectivity in the improved landscape and habitat availability increased substantially in response to small increases in habitat. The improved landscape revealed important habitat patches in the existing landscape that should be protected and developed. Conclusions Our findings highlight that optimal landscapes can be designed through the integration of habitat data with spatial metrics for a GFS. By adopting this novel approach, conservation strategies can be targeted in an efficient manner to conserve at-risk species and their associated habitats. Integrating these design principles with policy and practice could enhance biodiversity across Europe.

scholarly journals Evaluation of Traits for the Selection of Apis Mellifera for Resistance against Varroa Destructor

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 618 ◽  
Author(s):  
Ralph Büchler ◽  
Marin Kovačić ◽  
Martin Buchegger ◽  
Zlatko Puškadija ◽  
Andreas Hoppe ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Varroa Destructor ◽  
Infestation Rate ◽  
Mite Infestation ◽  
Behavioral Traits ◽  
Bee Colony ◽  
Mite Reproduction ◽  
Varroa Resistance ◽  
Colony Survival ◽  
Selection Of

Infestation with Varroa destructor is a serious cause of bee colony (Apis mellifera) losses on a global level. However, the presence of untreated survivor populations in many different regions supports the idea that selection for resistance can be successful. As colony survival is difficult or impossible to measure, differences in mite infestation levels and tests for specific behavioral traits are used for selective breeding for Varroa resistance. In this paper we looked into different definitions of mite infestation and linked these with brood hygiene (pin test), brood recapping and suppressed mite reproduction. We based our analyses on datasets of Apis mellifera carnica from three countries: Austria (147 records), Croatia (135) and Germany (207). We concluded that bee infestation in summer, adjusted for the level of natural mite fall in spring, is a suitable trait in the breeding objective, and also suggested including brood infestation rate and the increase rate of bee infestation in summer. Repeatability for bee infestation rate was about 0.55, for cells opened in pin test about 0.33, for recapping 0.35 and for suppressed mite reproduction (SMR) virtually zero. Although in most cases we observed correlations with the expected sign between infestation parameters and behavioral traits, the values were generally low (<0.2) and often not significantly different from zero.

scholarly journals Austrian COLOSS Survey of Honey Bee Colony Winter Losses 2018/19 and Analysis of Hive Management Practices

Diversity ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 99 ◽  
Author(s):  
Hannes Oberreiter ◽  
Robert Brodschneider
Keyword(s):  
Honey Bee ◽  
Management Practices ◽  
Favourable Effect ◽  
Winter Mortality ◽  
Colony Losses ◽  
Bee Colony ◽  
Honey Bee Colony ◽  
Colony Survival ◽  
The Impact ◽  
Loss Rates

We conducted a citizen science survey on overwinter honey bee colony losses in Austria. A total of 1534 beekeepers with 33,651 colonies reported valid loss rates. The total winter loss rate for Austria was 15.2% (95% confidence interval: 14.4–16.1%). Young queens showed a positive effect on colony survival and queen-related losses. Observed queen problems during the season increased the probability of losing colonies to unsolvable queen problems. A notable number of bees with crippled wings during the foraging season resulted in high losses and could serve as an alarm signal for beekeepers. Migratory beekeepers and large operations had lower loss rates than smaller ones. Additionally, we investigated the impact of several hive management practices. Most of them had no significant effect on winter mortality, but purchasing wax from outside the own operation was associated with higher loss rates. Colonies that reported foraging on maize and late catch crop fields or collecting melezitose exhibited higher loss rates. The most common Varroa destructor control methods were a combination of long-term formic acid treatment in summer and oxalic acid trickling in winter. Biotechnical methods in summer had a favourable effect on colony survival.

scholarly journals Wild pollinator activities negatively related to honey bee colony densities in urban context

2019 ◽  
Author(s):  
Lise Ropars ◽  
Isabelle Dajoz ◽  
Colin Fontaine ◽  
Audrey Muratet ◽  
Benoît Geslin
Keyword(s):  
Honey Bee ◽  
Honey Bees ◽  
Urban Areas ◽  
Pesticide Exposure ◽  
Floral Resources ◽  
Strong Increase ◽  
Pollinator Visitation ◽  
Pollinator Decline ◽  
Bee Colony ◽  
Honey Bee Colony

AbstractAs pollinator decline is increasingly reported in natural and agricultural environments, cities are perceived as shelters for pollinators because of low pesticide exposure and high floral diversity throughout the year. This has led to the development of environmental policies supporting pollinators in urban areas. However, policies are often restricted to the promotion of honey bee colony installations, which resulted in a strong increase in apiary numbers in cities. Recently, competition for floral resources between wild pollinators and honey bees has been highlighted in semi-natural contexts, but whether urban beekeeping could impact wild pollinators remains unknown. Here, we show that in the city of Paris (France), wild pollinator visitation rates is negatively correlated to honey bee colony densities present in the surrounding (500m – slope = −0.614; p = 0.001 – and 1000m – slope = −0.489; p = 0.005). More particularly, large solitary bees and beetles were significantly affected at 500m (respectively slope = −0.425, p = 0.007 and slope = - 0.671, p = 0.002) and bumblebees were significantly affected at 1000m (slope = - 0.451, p = 0.012). Further, lower interaction evenness in plant-pollinator networks was observed with honey bee colony densities within 1000 meter buffers (slope = −0.487, p = 0.008). Finally, honey bees tended to focus their foraging activity on managed rather than spontaneous plant species (student t-test, p = 0.001) whereas wild pollinators equally visited managed and spontaneous species. We advocate responsible practices mitigating the introduction of high density of hives in urban environments. Future studies are needed to deepen our knowledge about the potential negative interactions between wild and domesticated pollinators.

Effects of honey bee virus prevalence, Varroa destructor load and queen condition on honey bee colony survival over the winter in Belgium

2011 ◽  
Vol 50 (3) ◽  
pp. 195-202 ◽  
Author(s):  
Bach Kim Nguyen ◽  
Magali Ribière ◽  
Dennis vanEngelsdorp ◽  
Chantal Snoeck ◽  
Claude Saegerman ◽  
...  
Keyword(s):  
Honey Bee ◽  
Varroa Destructor ◽  
Virus Prevalence ◽  
Bee Colony ◽  
Honey Bee Colony ◽  
Colony Survival ◽  
Bee Virus

Electromagnetic fields in the presence of an infinite metamaterial wedge

2008 ◽  
Vol 464 (2096) ◽  
pp. 2077-2089 ◽  
Author(s):  
Mohamed A Salem ◽  
Aladin H Kamel
Keyword(s):  
Finite Difference ◽  
Frequency Domain ◽  
Integral Equations ◽  
Electromagnetic Fields ◽  
Singular Integral ◽  
Line Source ◽  
Numerical Scheme ◽  
Singular Integral Equations ◽  
Spectral Functions ◽  
Electric Line

Electromagnetic fields, excited by an electric line source in the presence of an infinite metamaterial wedge, are determined by application of the Kontorovich–Lebedev transform. Uncoupled singular integral equations for the spectral functions are derived and a numerical scheme is devised and implemented to solve them. Numerical results showing the influence of a metamaterial wedge presence on the directivity of a line source are presented and verified through finite-difference frequency-domain simulations.

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