Deformed wing virus coopts the host arginine kinase to enhance its fitness in honey bees (Apis mellifera).

Background: Deformed wing virus (DWV) is a major honey bee pathogen that is actively transmitted by the parasitic mite Varroa destructor and plays a primary role in Apis mellifera winter colony losses. Despite intense investigation on this pollinator, which has a unique environmental and economic importance, the mechanisms underlying the molecular interactions between DWV and honey bees are still poorly understood. Here, we report on a group of honey bee proteins, identified by mass spectrometry, that specifically co-immunoprecipitate with DWV virus particles.

Sequence-Based Multi Ancestry Association Study Reveals the Polygenic Architecture of Varroa destructor Resistance in the Honeybee Apis mellifera.

Honeybees, Apis mellifera, have experienced the full impacts of globalisation, including the recent invasion by the parasitic mite Varroa destructor, now one of the main causes of colony losses worldwide. The strong selection pressure it exerts has led some colonies to develop defence strategies conferring some degree of resistance to the parasite. Assuming these traits are partly heritable, selective breeding of naturally resistant bees could be a sustainable strategy for fighting infestations.

Assessing lethal and sublethal effects of pesticides on honey bees in a multifactorial context.

The registration of novel pesticides that are subsequently banned because of their unexpected negative effects on non-target species can have a huge environmental impact. Therefore, the pre-emptive evaluation of the potential effects of new compounds is essential. To this aim both lethal and sublethal effects should be assessed in a realistic scenario including the other stressors that can interact with pesticides.

Varroa destructor shapes the unique viral landscapes of the honey bee populations of the Azores archipelago.

The worldwide dispersal of the ectoparasitic mite Varroa destructor from its Asian origins has fundamentally transformed the relationship of the honey bee (Apis mellifera) with several of its viruses, via changes in transmission and/or host immunosuppression. The extent to which honey bee-virus relationships change after Varroa invasion is poorly understood for most viruses, in part because there are few places in the world with several geographically close but completely isolated honey bee populations that either have, or have not, been exposed long-term to Varroa, allowing for separate ecological, epidemiological, and adaptive relationships to develop between honey bees and their viruses, in relation to the mite's presence or absence. The Azores is one such place, as it contains islands with and without the mite.

Novel indices reveal that pollinator exposure to pesticides varies across biological compartments and crop surroundings.

Declines in insect pollinators have been linked to a range of causative factors such as disease, loss of habitats, the quality and availability of food, and exposure to pesticides. Here, we analysed an extensive dataset generated from pesticide screening of foraging insects, pollen-nectar stores/beebread, pollen and ingested nectar across three species of bees collected at 128 European sites set in two types of crop. In this paper, we aimed to (i) derive a new index to summarise key aspects of complex pesticide exposure data and (ii) understand the links between pesticide exposures depicted by the different matrices, bee species and apple orchards versus oilseed rape crops.

Distribution of infectious and parasitic agents among three sentinel bee species across European agricultural landscapes.

Infectious and parasitic agents (IPAs) and their associated diseases are major environmental stressors that jeopardize bee health, both alone and in interaction with other stressors. Their impact on pollinator communities can be assessed by studying multiple sentinel bee species. Here, we analysed the field exposure of three sentinel managed bee species (Apis mellifera, Bombus terrestris and Osmia bicornis) to 11 IPAs (six RNA viruses, two bacteria, three microsporidia).

Shift in virus composition in honeybees () following worldwide invasion by the parasitic mite and virus vector .

Invasive vectors can induce dramatic changes in disease epidemiology. While viral emergence following geographical range expansion of a vector is well known, the influence a vector can have at the level of the host's pathobiome is less well understood. Taking advantage of the formerly heterogeneous spatial distribution of the ectoparasitic mite that acts as potent virus vector among honeybees , we investigated the impact of its recent global spread on the viral community of honeybees in a retrospective study of historical samples.

Pesticide use negatively affects bumble bees across European landscapes.

Sustainable agriculture requires balancing crop yields with the effects of pesticides on non-target organisms, such as bees and other crop pollinators. Field studies demonstrated that agricultural use of neonicotinoid insecticides can negatively affect wild bee species, leading to restrictions on these compounds. However, besides neonicotinoids, field-based evidence of the effects of landscape pesticide exposure on wild bees is lacking.

Gut microbiota assembly of Gotland varroa-surviving honey bees excludes major viral pathogens.

The spread of the parasite Varroa destructor and associated viruses has resulted in massive honey bee colony losses with considerable economic and ecological impact. The gut microbiota has a major role in shaping honey bees tolerance and resistance to parasite infestation and viral infection, but the contribution of viruses to the assembly of the host microbiota in the context of varroa resistance and susceptibility remains unclear. Here, we used a network approach including viral and bacterial nodes to characterize the impact of five viruses, Apis Rhabdovirus-1 (ARV-1), Black Queen Cell virus (BQCV), Lake Sinai virus (LSV), Sacbrood virus (SBV) and Deformed wing virus (DWV) on the gut microbiota assembly of varroa-susceptible and Gotland varroa-surviving honey bees.

Host brood traits, independent of adult behaviours, reduce Varroa destructor mite reproduction in resistant honeybee populations.

The ectoparasitic mite Varroa destructor is an invasive species of Western honey bees (Apis mellifera) and the largest pathogenic threat to their health world-wide. Its successful invasion and expansion is related to its ability to exploit the worker brood for reproduction, which results in an exponential population growth rate in the new host. With invasion of the mite, wild honeybee populations have been nearly eradicated from Europe and North America, and the survival of managed honeybee populations relies on mite population control treatments.

Ecological traits interact with landscape context to determine bees' pesticide risk.

Widespread contamination of ecosystems with pesticides threatens non-target organisms. However, the extent to which life-history traits affect pesticide exposure and resulting risk in different landscape contexts remains poorly understood. We address this for bees across an agricultural land-use gradient based on pesticide assays of pollen and nectar collected by Apis mellifera, Bombus terrestris and Osmia bicornis, representing extensive, intermediate and limited foraging traits.

Virus Prevalence in Egg Samples Collected from Naturally Selected and Traditionally Managed Honey Bee Colonies across Europe.

Monitoring virus infections can be an important selection tool in honey bee breeding. A recent study pointed towards an association between the virus-free status of eggs and an increased virus resistance to deformed wing virus (DWV) at the colony level. In this study, eggs from both naturally surviving and traditionally managed colonies from across Europe were screened for the prevalence of different viruses.

Genomic divergence and a lack of recent introgression between commercial and wild bumblebees ().

The global movement of bees for agricultural pollination services can affect local pollinator populations via hybridization. When commercial bumblebees are of the same species but of different geographic origin, intraspecific hybridization may result in beneficial integration of new genetic variation, or alternatively may disrupt locally adapted gene complexes. However, neither the existence nor the extent of genomic introgression and evolutionary divergence between wild and commercial bumblebees is fully understood.

Honey bees and climate explain viral prevalence in wild bee communities on a continental scale.

Viruses are omnipresent, yet the knowledge on drivers of viral prevalence in wild host populations is often limited. Biotic factors, such as sympatric managed host species, as well as abiotic factors, such as climatic variables, are likely to impact viral prevalence. Managed and wild bees, which harbor several multi-host viruses with a mostly fecal-oral between-species transmission route, provide an excellent system with which to test for the impact of biotic and abiotic factors on viral prevalence in wild host populations.

Genetic characterisation of an Iflavirus associated with a vomiting disease in the Indian tropical tasar silkworm, Antheraea mylitta.

Antheraea mylitta, the Tropical tasar silkworm, is frequently affected by a vomiting disease called Virosis by sericulturists although not confirmed being of viral origin. Based on the symptoms and the disease pattern, the causal agent is however suspected to be a virus. The condition involves a series of characteristic and progressive symptoms that generally culminates in the death of the larva.

Cold case: The disappearance of Egypt bee virus, a fourth distinct master strain of deformed wing virus linked to honeybee mortality in 1970's Egypt.

In 1977, a sample of diseased adult honeybees (Apis mellifera) from Egypt was found to contain large amounts of a previously unknown virus, Egypt bee virus, which was subsequently shown to be serologically related to deformed wing virus (DWV). By sequencing the original isolate, we demonstrate that Egypt bee virus is in fact a fourth unique, major variant of DWV (DWV-D): more closely related to DWV-C than to either DWV-A or DWV-B. DWV-A and DWV-B are the most common DWV variants worldwide due to their close relationship and transmission by Varroa destructor.

Global similarity, and some key differences, in the metagenomes of Swedish varroa-surviving and varroa-susceptible honeybees.

There is increasing evidence that honeybees (Apis mellifera L.) can adapt naturally to survive Varroa destructor, the primary cause of colony mortality world-wide. Most of the adaptive traits of naturally varroa-surviving honeybees concern varroa reproduction.

Adapted tolerance to virus infections in four geographically distinct Varroa destructor-resistant honeybee populations.

The ectoparasitic mite, Varroa destructor, is unarguably the leading cause of honeybee (Apis mellifera) mortality worldwide through its role as a vector for lethal viruses, in particular, strains of the Deformed wing virus (DWV) and Acute bee paralysis virus (ABPV) complexes. Several honeybee populations across Europe have well-documented adaptations of mite-resistant traits but little is known about host adaptations towards the virus infections vectored by the mite. The aim of this study was to assess and compare the possible contribution of adapted virus tolerance and/or resistance to the enhanced survival of four well-documented mite-resistant honeybee populations from Norway, Sweden, The Netherlands and France, in relation to unselected mite-susceptible honeybees.

Virus Diversity and Loads in Crickets Reared for Feed: Implications for Husbandry.

Insects generally have high reproductive rates leading to rapid population growth and high local densities; ideal conditions for disease epidemics. The parasites and diseases that naturally regulate wild insect populations can also impact when these insects are produced commercially, on farms. While insects produced for human or animal consumption are often reared under high density conditions, very little is known about the microbes associated with these insects, particularly those with pathogenic potential.

Development and optimization of a TaqMan assay for Nosema bombycis, causative agent of pébrine disease in Bombyx mori silkworm, based on the β-tubulin gene.

"Pébrine" is a devastating disease of Bombyx mori silkworms that is highly contagious and can completely destroy an entire crop of silkworms and is thus a serious threat for the viability and profitability of sericulture. The disease is most commonly attributed to microsporidians of the genus Nosema, which are obligate intracellular parasites that are transmitted through spores. Nosema infections in silkworms are diagnosed primarily through light microscopy, which is labour intensive and less reliable, sensitive, and specific than PCR-based techniques.

Managed bumble bees acquire parasites from their foraging environment: A case study on parasite spillback.

The use of commercially reared bumble bees in agricultural environments has been recognized as a potential threat to wild pollinators due to competition, genetic contamination, and most notably, disease transmission. Higher parasite prevalence near greenhouses where managed bumble bees are used has been linked to parasite spillover from managed to wild bees. However, pathogen transmission is not unidirectional, and can also flow from wild to managed bees.

Virus Prospecting in Crickets-Discovery and Strain Divergence of a Novel Iflavirus in Wild and Cultivated .

Orthopteran insects have high reproductive rates leading to boom-bust population dynamics with high local densities that are ideal for short, episodic disease epidemics. Viruses are particularly well suited for such host population dynamics, due to their supreme ability to adapt to changing transmission criteria. However, very little is known about the viruses of Orthopteran insects.