The Pathogen Profile of a Honey Bee Queen Does Not Reflect That of Her Workers

Nano-managing silver and zinc as bio-conservational approach against pathogens of the honey bee

Herein, silver and zinc oxide Nanoparticles (NPs) were synthesized by using W. coagulant fruit extract as reducing agent and capping agent. The green synthesized NP with distinct properties were used for novel application against fungal and bacterial pathogen of honey bee (A. mellifera). The UV-spectroscopy confirms the synthesis of silver and zinc oxide NPs at 420 nm and 350 nm respectively. Further, XRD evaluated the monoclinic structure of Ag NPs while ZnO NPs showed wurtzite hexagonalcrystlized structure. Resistant honey bee pathogens such Paenibacilluslarvae, Melissococcus plutonius and Ascosphaera apis were isolated, identified and cultured in vitro to assess the antimicrobial potentials of Ag and ZnO NPs. Additionally, different biomolecules provide access to achieve maximum and stable Ag and ZnO NPs. It was also observed that with increasing the concentration of zinc oxide NPs and sliver NPs, zone of inhibition was also increased. Thus, present findings show that plant extracts can be a useful natural resource to prepare functional nonmaterial for targeted applications especially in the field of apicultural research.

Enhancement of antiviral activity of egg yolk antibodies against Chinese sacbrood virus

Chinese sacbrood virus (CSBV) poses a serious threat to the apiculture of China. Although several approaches have been attempted to control CSBV infection, their applications have been greatly limited in practical breeding of honeybees due to poor effectiveness. Egg yolk antibodies (EYA) have shown a promising protection for bees against CSBV infection. This study was conducted to produce high titer EYA and then further improve their antiviral effect. Among three vaccination groups, the EYA titer in graphene oxide-chitosan group was highest (1.591 ± 0.145), in Freund's group was modest (1.195 ± 0.040), and in white oil group was lowest (1.058 ± 0.056). After three injections of each vaccine in hens, EYA were produced at the highest level with a 14-day period. After application of EYA for more than two years in actual bee breeding, prevention and treatment assays showed that EYA confered 98.9 to 100% protection from CSBV infection. The mortality of the control group reached to a range of 91.2 to 100%. This study demonstrated that the high titer EYA have been successfully prepared with significant anti-CSBV activity and that these antibodies may feasibly be used for CSBV treatment to meet the practical needs of apiculture.

Sociality and parasite transmission

Parasites and their social hosts form many different relationships. But what kind of selection regimes are important? A look at the parameters that determine fitness of the two parties suggests that social hosts differ from solitary ones primarily in the structure of transmission pathways. Because transmission is, both, the physical encounter of a new host and infecting it, several different elements determine parasite transmission success. These include spatial distance, genetic distance, or the temporal and ecological niche overlaps. Combing these elements into a ‘generalized transmission distance’ that determines parasite fitness aids in the identification of the critical steps. For example, short-distance transmission to genetically similar hosts within the social group is the most frequent process under sociality. Therefore, spatio-genetical distances are the main driver of parasite fitness. Vice versa, the generalized distance identifies the critical host defences. In this case, host defences should be primarily selected to defend against the within-group spread of an infection, especially among closely related group members.

Breeding for Virus Resistance and Its Effects on Deformed Wing Virus Infection Patterns in Honey Bee Queens

Viruses, and in particular the deformed wing virus (DWV), are considered as one of the main antagonists of honey bee health. The 'suppressed in ovo virus infection' trait (SOV) described for the first time that control of a virus infection can be achieved from genetically inherited traits and that the virus state of the eggs is indicative for this. This research aims to explore the effect of the SOV trait on DWV infections in queens descending from both SOV-positive (QDS+) and SOV-negative (QDS-) queens. Twenty QDS+ and QDS- were reared from each time four queens in the same starter-finisher colony. From each queen the head, thorax, ovaries, spermatheca, guts and eviscerated abdomen were dissected and screened for the presence of the DWV-A and DWV-B genotype using qRT-PCR. Queens descending from SOV-positive queens showed significant lower infection loads for DWV-A and DWV-B as well as a lower number of infected tissues for DWV-A. Surprisingly, differences were less expressed in the reproductive tissues, the ovaries and spermatheca. These results confirm that selection on the SOV trait is associated with increased virus resistance across viral genotypes and that this selection drives DWV towards an increased tissue specificity for the reproductive tissues. Further research is needed to explore the mechanisms underlying the interaction between the antiviral response and DWV.

Introduction of Varroa destructor has not altered honey bee queen mating success in the Hawaiian archipelago

Beekeepers struggle to minimize the mortality of their colonies as a consequence of the parasitic mite Varroa destructor in order to maintain a sustainable managed pollinator population. However, little is known about how varroa mites might diminish local populations of honey bee males (drones) that might affect the mating success of queens. As one of the world's last localities invaded by varroa mites, the Hawaiian Islands offer a unique opportunity to examine this question by comparing queens mated on mite-infested and mite-free islands. We raised queen bees on four Hawaiian Islands (Kaua'i, O'ahu, Maui, and Hawai'i) and subsequently collected their offspring to determine queen mating frequency and insemination success. No significant difference for mating success was found between the islands with and without varroa mites, and relatively high levels of polyandry was detected overall. We also found a significant association between the number of sperm stored in the queens' spermathecae and the number of managed colonies within the localities of the queens mated. Our findings suggest that varroa mites, as they currently occur in Hawai'i, may not significantly reduce mating success of honey bee queens, which provides insight for both the reproductive biology of honey bees as well as the apiculture industry in Hawai'i.

Comparing Survival of Israeli Acute Paralysis Virus Infection among Stocks of U.S. Honey Bees

Simple Summary

Honey bees and other pollinators are threatened by numerous stressors, including virus infections. Currently, no effective treatments are available, stressing the importance of natural defenses. These defenses may be enhanced through selective breeding. This study sought to evaluate the potential for breeding, while also testing a few potential mechanisms of natural immune responses and assessing how widespread viruses are in commercial honey bee queens in the U.S. We identified significant differences in survival of virus infection among and within U.S honey bee stocks, indicating that selective breeding may be able to decrease the virus susceptibility of honey bees. Survival differences may be related to differences in the natural immune system of honey bees and could relate to how much virus stress bees have experienced in the past.

Abstract

Among numerous viruses that infect honey bees (Apis mellifera), Israeli acute paralysis virus (IAPV) can be linked to severe honey bee health problems. Breeding for virus resistance may improve honey bee health. To evaluate the potential for this approach, we compared the survival of IAPV infection among stocks from the U.S. We complemented the survival analysis with a survey of existing viruses in these stocks and assessing constitutive and induced expression of immune genes. Worker offspring from selected queens in a common apiary were inoculated with IAPV by topical applications after emergence to assess subsequent survival. Differences among stocks were small compared to variation within stocks, indicating the potential for improving honey bee survival of virus infections in all stocks. A positive relation between worker survival and virus load among stocks further suggested that honey bees may be able to adapt to better cope with viruses, while our molecular studies indicate that toll-6 may be related to survival differences among virus-infected worker bees. Together, these findings highlight the importance of viruses in queen breeding operations and provide a promising starting point for the quest to improve honey bee health by selectively breeding stock to be better able to survive virus infections.

Veterinary Diagnostic Approach of Common Virus Diseases in Adult Honeybees

Veterinarians are educated in prevention, diagnosis and treatment of diseases in various vertebrate species. As they are familiar with multifactorial health problems in single animals as well as in herd health management, their knowledge and skills can be beneficial for the beekeepers and honeybee health. However, in education and in practice, honeybees are not a common species for most veterinarians and the typical veterinary diagnostic methods such as blood sampling or auscultation are not applicable to the superorganism honeybee. Honeybee colonies may be affected by various biotic and abiotic factors. Among the infectious agents, RNA-viruses build the largest group, causing covert and overt infections in honeybee colonies which may lead to colony losses. Veterinarians could and should play a more substantial role in managing honeybee health—not limited to cases of notifiable diseases and official hygiene controls. This review discusses the veterinary diagnostic approach to adult bee examination with a special focus on diagnosis and differential diagnosis of the common virus diseases Acute Bee Paralysis Virus (ABPV)-Kashmir Bee Virus (KBV)-Israeli Acute Paralysis Virus (IAPV)-Complex, Chronic Bee Paralysis Virus (CBPV) and Deformed Wing Virus (DWV), as well as coinfections like Varroa spp. and Nosema spp.