Research

Jump to: Review

2076 KiB

Open AccessArticle

Comparative Flight Activities and Pathogen Load of Two Stocks of Honey Bees Reared in Gamma-Irradiated Combs

by Lilia I. De Guzman, Amanda M. Frake and Michael Simone-Finstrom

Insects 2017, 8(4), 127; https://doi.org/10.3390/insects8040127 - 29 Nov 2017

Cited by 13 | Viewed by 5284

Gamma irradiation is known to inactivate various pathogens that negatively affect honey bee health. Bee pathogens, such as Deformed wing virus (DWV) and Nosema spp., have a deleterious impact on foraging activities and bee survival, and have been detected in combs. In this [...] Read more.

Gamma irradiation is known to inactivate various pathogens that negatively affect honey bee health. Bee pathogens, such as Deformed wing virus (DWV) and Nosema spp., have a deleterious impact on foraging activities and bee survival, and have been detected in combs. In this study, we assessed the effects of gamma irradiation on the flight activities, pathogen load, and survival of two honey bee stocks that were reared in irradiated and non-irradiated combs. Overall, bee genotype influenced the average number of daily flights, the total number of foraging flights, and total flight duration, in which the Russian honey bees outperformed the Italian honey bees. Exposing combs to gamma irradiation only affected the age at first flight, with worker bees that were reared in non-irradiated combs foraging prematurely compared to those reared in irradiated combs. Precocious foraging may be associated with the higher levels of DWV in bees reared in non-irradiated combs and also with the lower amount of pollen stores in colonies that used non-irradiated combs. These data suggest that gamma irradiation of combs can help minimize the negative impact of DWV in honey bees. Since colonies with irradiated combs stored more pollen than those with non-irradiated combs, crop pollination efficiency may be further improved when mite-resistant stocks are used, since they performed more flights and had longer flight durations. Full article

(This article belongs to the Special Issue Interactions Among Threats to Honeybee Health)

► Show Figures

Graphical abstract

2512 KiB

Open AccessArticle

Bee++: An Object-Oriented, Agent-Based Simulator for Honey Bee Colonies

by Matthew Betti, Josh LeClair, Lindi M. Wahl and Mair Zamir

Insects 2017, 8(1), 31; https://doi.org/10.3390/insects8010031 - 10 Mar 2017

Cited by 12 | Viewed by 7899

Abstract

We present a model and associated simulation package (www.beeplusplus.ca) to capture the natural dynamics of a honey bee colony in a spatially-explicit landscape, with temporally-variable, weather-dependent parameters. The simulation tracks bees of different ages and castes, food stores within the colony, pollen and [...] Read more.

We present a model and associated simulation package (www.beeplusplus.ca) to capture the natural dynamics of a honey bee colony in a spatially-explicit landscape, with temporally-variable, weather-dependent parameters. The simulation tracks bees of different ages and castes, food stores within the colony, pollen and nectar sources and the spatial position of individual foragers outside the hive. We track explicitly the intake of pesticides in individual bees and their ability to metabolize these toxins, such that the impact of sub-lethal doses of pesticides can be explored. Moreover, pathogen populations (in particular, Nosema apis, Nosema cerenae and Varroa mites) have been included in the model and may be introduced at any time or location. The ability to study interactions among pesticides, climate, biodiversity and pathogens in this predictive framework should prove useful to a wide range of researchers studying honey bee populations. To this end, the simulation package is written in open source, object-oriented code (C++) and can be easily modiﬁed by the user. Here, we demonstrate the use of the model by exploring the effects of sub-lethal pesticide exposure on the ﬂight behaviour of foragers. Full article

(This article belongs to the Special Issue Interactions Among Threats to Honeybee Health)

► Show Figures

Figure 1

1516 KiB

Open AccessArticle

A Comparison of Deformed Wing Virus in Deformed and Asymptomatic Honey Bees

by Laura E. Brettell, Gideon J. Mordecai, Declan C. Schroeder, Ian M. Jones, Jessica R. Da Silva, Marina Vicente-Rubiano and Stephen J. Martin

Insects 2017, 8(1), 28; https://doi.org/10.3390/insects8010028 - 07 Mar 2017

Cited by 44 | Viewed by 9645

Abstract

Deformed wing virus (DWV) in association with Varroa destructor is currently attributed to being responsible for colony collapse in the western honey bee (Apis mellifera). The appearance of deformed individuals within an infested colony has long been associated with colony losses. [...] Read more.

Deformed wing virus (DWV) in association with Varroa destructor is currently attributed to being responsible for colony collapse in the western honey bee (Apis mellifera). The appearance of deformed individuals within an infested colony has long been associated with colony losses. However, it is unknown why only a fraction of DWV positive bees develop deformed wings. This study concerns two small studies comparing deformed and non-deformed bees. In Brazil, asymptomatic bees (no wing deformity) that had been parasitised by Varroa as pupae had higher DWV loads than non-parasitised bees. However, we found no greater bilateral asymmetry in wing morphology due to DWV titres or parasitisation. As expected, using RT-qPCR, deformed bees were found to contain the highest viral loads. In a separate study, next generation sequencing (NGS) was applied to compare the entire DWV genomes from paired symptomatic and asymptomatic bees from three colonies on two different Hawaiian islands. This revealed no consistent differences between DWV genomes from deformed or asymptomatic bees, with the greatest variation seen between locations, not phenotypes. All samples, except one, were dominated by DWV type A. This small-scale study suggests that there is no unique genetic variant associated with wing deformity; but that many DWV variants have the potential to cause deformity. Full article

(This article belongs to the Special Issue Interactions Among Threats to Honeybee Health)

► Show Figures

Figure 1

1606 KiB

Open AccessArticle

Impacts of Dietary Phytochemicals in the Presence and Absence of Pesticides on Longevity of Honey Bees (Apis mellifera)

by Ling-Hsiu Liao, Wen-Yen Wu and May R. Berenbaum

Insects 2017, 8(1), 22; https://doi.org/10.3390/insects8010022 - 14 Feb 2017

Cited by 48 | Viewed by 10358

Abstract

Because certain flavonols and phenolic acids are found in pollen and nectar of most angiosperms, they are routinely ingested by Apis mellifera, the western honey bee. The flavonol quercetin and the phenolic acid p-coumaric acid are known to upregulate detoxification enzymes [...] Read more.

Because certain flavonols and phenolic acids are found in pollen and nectar of most angiosperms, they are routinely ingested by Apis mellifera, the western honey bee. The flavonol quercetin and the phenolic acid p-coumaric acid are known to upregulate detoxification enzymes in adult bees; their presence or absence in the diet may thus affect the toxicity of ingested pesticides. We conducted a series of longevity assays with one-day-old adult workers to test if dietary phytochemicals enhance longevity and pesticide tolerance. One-day-old bees were maintained on sugar syrup with or without casein (a phytochemical-free protein source) in the presence or absence of quercetin and p-coumaric acid as well as in the presence or absence of two pyrethroid insecticides, bifenthrin and β-cyfluthrin. Dietary quercetin (hazard ratio, HR = 0.82), p-coumaric acid (HR = 0.91) and casein (HR = 0.74) were associated with extended lifespan and the two pyrethroid insecticides, 4 ppm bifenthrin (HR = 9.17) and 0.5 ppm β-cyfluthrin (HR = 1.34), reduced lifespan. Dietary quercetin enhanced tolerance of both pyrethroids; p-coumaric acid had a similar effect trend, although of reduced magnitude. Casein in the diet appears to eliminate the life-prolonging effect of p-coumaric acid in the absence of quercetin. Collectively, these assays demonstrate that dietary phytochemicals influence honey bee longevity and pesticide stress; substituting sugar syrups for honey or yeast/soy flour patties may thus have hitherto unrecognized impacts on adult bee health. Full article

(This article belongs to the Special Issue Interactions Among Threats to Honeybee Health)

► Show Figures

Figure 1

939 KiB

Open AccessArticle

Cold Ambient Temperature Promotes Nosema spp. Intensity in Honey Bees (Apis mellifera)

by Gina Retschnig, Geoffrey R. Williams, Annette Schneeberger and Peter Neumann

Insects 2017, 8(1), 20; https://doi.org/10.3390/insects8010020 - 09 Feb 2017

Cited by 34 | Viewed by 5967

Abstract

Interactions between parasites and environmental factors have been implicated in the loss of managed Western honey bee (=HB, Apis mellifera) colonies. Although laboratory data suggest that cold temperature may limit the spread of Nosema ceranae, an invasive species and now ubiquitous [...] Read more.

Interactions between parasites and environmental factors have been implicated in the loss of managed Western honey bee (=HB, Apis mellifera) colonies. Although laboratory data suggest that cold temperature may limit the spread of Nosema ceranae, an invasive species and now ubiquitous endoparasite of Western HBs, the impact of weather conditions on the distribution of this microsporidian in the field is poorly understood. Here, we conducted a survey for Nosema spp. using 18 Swiss apiaries (four colonies per apiary) over a period of up to 18 months. Samples consisting of 60 workers were collected monthly from each colony to estimate Nosema spp. intensity, i.e., the number of spores in positive samples using microscopy. Ambient apiary temperature was measured daily to estimate the proportion of days enabling HB flight (>10 °C at midday). The results show that Nosema spp. intensities were negatively correlated with the proportion of days enabling HB flight, thereby suggesting a significant and unexpected positive impact of cold ambient temperature on intensities, probably via regulation of defecation opportunities for infected hosts. Full article

(This article belongs to the Special Issue Interactions Among Threats to Honeybee Health)

► Show Figures

Figure 1

1304 KiB

Open AccessFeature PaperArticle

Inside Honeybee Hives: Impact of Natural Propolis on the Ectoparasitic Mite Varroa destructor and Viruses

by Nora Drescher, Alexandra-Maria Klein, Peter Neumann, Orlando Yañez and Sara D. Leonhardt

Insects 2017, 8(1), 15; https://doi.org/10.3390/insects8010015 - 06 Feb 2017

Cited by 48 | Viewed by 11476

Abstract

Social immunity is a key factor for honeybee health, including behavioral defense strategies such as the collective use of antimicrobial plant resins (propolis). While laboratory data repeatedly show significant propolis effects, field data are scarce, especially at the colony level. Here, we investigated [...] Read more.

Social immunity is a key factor for honeybee health, including behavioral defense strategies such as the collective use of antimicrobial plant resins (propolis). While laboratory data repeatedly show significant propolis effects, field data are scarce, especially at the colony level. Here, we investigated whether propolis, as naturally deposited in the nests, can protect honeybees against ectoparasitic mites Varroa destructor and associated viruses, which are currently considered the most serious biological threat to European honeybee subspecies, Apis mellifera, globally. Propolis intake of 10 field colonies was manipulated by either reducing or adding freshly collected propolis. Mite infestations, titers of deformed wing virus (DWV) and sacbrood virus (SBV), resin intake, as well as colony strength were recorded monthly from July to September 2013. We additionally examined the effect of raw propolis volatiles on mite survival in laboratory assays. Our results showed no significant effects of adding or removing propolis on mite survival and infestation levels. However, in relation to V. destructor, DWV titers increased significantly less in colonies with added propolis than in propolis-removed colonies, whereas SBV titers were similar. Colonies with added propolis were also significantly stronger than propolis-removed colonies. These findings indicate that propolis may interfere with the dynamics of V. destructor-transmitted viruses, thereby further emphasizing the importance of propolis for honeybee health. Full article

(This article belongs to the Special Issue Interactions Among Threats to Honeybee Health)

► Show Figures

Figure 1

1057 KiB

Open AccessArticle

Influence of Varroa Mite (Varroa destructor) Management Practices on Insecticide Sensitivity in the Honey Bee (Apis mellifera)

by Frank D. Rinkevich, Robert G. Danka and Kristen B. Healy

Insects 2017, 8(1), 9; https://doi.org/10.3390/insects8010009 - 11 Jan 2017

Cited by 22 | Viewed by 8290

Abstract

Since Varroa mites may cause devastating losses of honey bees through direct feeding, transmitting diseases, and increasing pathogen susceptibility, chemical and mechanical practices commonly are used to reduce mite infestation. While miticide applications are typically the most consistent and efficacious Varroa mite management [...] Read more.

Since Varroa mites may cause devastating losses of honey bees through direct feeding, transmitting diseases, and increasing pathogen susceptibility, chemical and mechanical practices commonly are used to reduce mite infestation. While miticide applications are typically the most consistent and efficacious Varroa mite management method, miticide-induced insecticide synergism in honey bees, and the evolution of resistance in Varroa mites are reasonable concerns. We treated colonies with the miticide amitraz (Apivar^®), used IPM practices, or left some colonies untreated, and then measured the effect of different levels of mite infestations on the sensitivity of bees to phenothrin, amitraz, and clothianidin. Sensitivity to all insecticides varied throughout the year among and within treatment groups. Clothianidin sensitivity decreased with increasing mite levels, but no such correlation was seen with phenothrin or amitraz. These results show that insecticide sensitivity is dynamic throughout the 5 months test. In-hive amitraz treatment according to the labeled use did not synergize sensitivity to the pesticides tested and this should alleviate concern over potential synergistic effects. Since IPM practices were largely ineffective at reducing Varroa mite infestation, reliance on chemical methods of Varroa mite management is likely to continue. However, miticides must be used judiciously so the long term effectiveness of these compounds can be maximized. These data demonstrate the complex and dynamic variables that contribute to honey bee colony health. The results underscore the importance of controlling for as many of these variables as possible in order to accurately determine the effects of each of these factors as they act alone or in concert with others. Full article

(This article belongs to the Special Issue Interactions Among Threats to Honeybee Health)

► Show Figures

Figure 1

Review

Jump to: Research

286 KiB

Open AccessReview

Queen Quality and the Impact of Honey Bee Diseases on Queen Health: Potential for Interactions between Two Major Threats to Colony Health

by Esmaeil Amiri, Micheline K. Strand, Olav Rueppell and David R. Tarpy

Insects 2017, 8(2), 48; https://doi.org/10.3390/insects8020048 - 08 May 2017

Cited by 96 | Viewed by 17704

Abstract

Western honey bees, Apis mellifera, live in highly eusocial colonies that are each typically headed by a single queen. The queen is the sole reproductive female in a healthy colony, and because long-term colony survival depends on her ability to produce a [...] Read more.

Western honey bees, Apis mellifera, live in highly eusocial colonies that are each typically headed by a single queen. The queen is the sole reproductive female in a healthy colony, and because long-term colony survival depends on her ability to produce a large number of offspring, queen health is essential for colony success. Honey bees have recently been experiencing considerable declines in colony health. Among a number of biotic and abiotic factors known to impact colony health, disease and queen failure are repeatedly reported as important factors underlying colony losses. Surprisingly, there are relatively few studies on the relationship and interaction between honey bee diseases and queen quality. It is critical to understand the negative impacts of pests and pathogens on queen health, how queen problems might enable disease, and how both factors influence colony health. Here, we review the current literature on queen reproductive potential and the impacts of honey bee parasites and pathogens on queens. We conclude by highlighting gaps in our knowledge on the combination of disease and queen failure to provide a perspective and prioritize further research to mitigate disease, improve queen quality, and ensure colony health. Full article

(This article belongs to the Special Issue Interactions Among Threats to Honeybee Health)

► Show Figures

Graphical abstract

2476 KiB

Open AccessReview

Propolis Counteracts Some Threats to Honey Bee Health

by Michael Simone-Finstrom, Renata S. Borba, Michael Wilson and Marla Spivak

Insects 2017, 8(2), 46; https://doi.org/10.3390/insects8020046 - 29 Apr 2017

Cited by 102 | Viewed by 19879

Abstract

Honey bees (Apis mellifera) are constantly dealing with threats from pathogens, pests, pesticides and poor nutrition. It is critically important to understand how honey bees’ natural immune responses (individual immunity) and collective behavioral defenses (social immunity) can improve bee health and [...] Read more.

Honey bees (Apis mellifera) are constantly dealing with threats from pathogens, pests, pesticides and poor nutrition. It is critically important to understand how honey bees’ natural immune responses (individual immunity) and collective behavioral defenses (social immunity) can improve bee health and productivity. One form of social immunity in honey bee colonies is the collection of antimicrobial plant resins and their use in the nest architecture as propolis. We review research on the constitutive benefits of propolis on the honey bee immune system, and its known therapeutic, colony-level effects against the pathogens Paenibacillus larvae and Ascosphaera apis. We also review the limited research on the effects of propolis against other pathogens, parasites and pests (Nosema, viruses, Varroa destructor, and hive beetles) and how propolis may enhance bee products such as royal jelly and honey. Although propolis may be a source of pesticide contamination, it also has the potential to be a detoxifying agent or primer of detoxification pathways, as well as increasing bee longevity via antioxidant-related pathways. Throughout this paper, we discuss opportunities for future research goals and present ways in which the beekeeping community can promote propolis use in standard colonies, as one way to improve and maintain colony health and resiliency. Full article

(This article belongs to the Special Issue Interactions Among Threats to Honeybee Health)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Interactions Among Threats to Honeybee Health

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (9 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI