Western Honey Bee Apis Mellifera Research Articles

Prevalence of the Microsporidian Nosema spp. in Honey Bee Populations (Apis mellifera) in Some Ecological Regions of North Asia.

Two species of microsporidia, Nosema apis and Nosema ceranae, are obligate intracellular parasites that are widespread in the world and cause the infectious disease (Nosemosis) of the Western honey bee Apis mellifera. Information on the prevalence and distribution of Nosema species in North Asia conditions is scarce. The main aim of the present study is to determine the prevalence of Nosema spp. (Nosemosis) in honey bees inhabiting some inland regions of North Asia (Western and Eastern Siberia, Altai Territory, Russia, and northeastern part of Kazakhstan). The objective of the paper is also to assess the influence of climatic factors on the spread of N. ceranae. Eighty apiaries in four ecological regions of North Asia (southern taiga, sub-taiga zone, forest steppe, and mountain taiga forests) were investigated with regard to distribution, prevalence, and diversity of Nosema infection in honey bees using duplex-PCR. Nosema infected bees were found in 65% apiaries of ecoregions studied, and coinfection was predominant (36.3% of Nosema-positive apiaries). Both N. apis and N. ceranae occur across subarctic and warm summer continental climates, but while N. apis predominates in the former, N. ceranae is more predominant in the latter. No statistically significant differences in Nosema distribution were identified in various climatic zones. In the sub-taiga zone (subarctic climate), low presence of colonies with pure N. ceranae and a significantly higher proportion of coinfection apiaries were revealed. Long-term epidemiological study of Nosema spp. prevalence in the sub-taiga zone showed a surprising percentage increase of Nosema-positive apiaries from 46.2% to 74.1% during 2012–2017. From 2012 to 2015, N. apis became a predominant species, but in 2016–2017, the coinfection was mainly detected. In conclusion, the results of this investigation showed that N. ceranae is widespread in all study ecoregions of North Asia where it exists in combination with the N. apis, but there is no replacement of N. apis by N. ceranae in the studied bee populations.

Slumber in a cell: honeycomb used by honey bees for food, brood, heating… and sleeping.

Sleep appears to play an important role in the lives of honey bees, but to understand how and why, it is essential to accurately identify sleep, and to know when and where it occurs. Viewing normally obscured honey bees in their nests would be necessary to calculate the total quantity and quality of sleep and sleep’s relevance to the health and dynamics of a honey bee and its colony. Western honey bees (Apis mellifera) spend much of their time inside cells, and are visible only by the tips of their abdomens when viewed through the walls of an observation hive, or on frames pulled from a typical beehive. Prior studies have suggested that honey bees spend some of their time inside cells resting or sleeping, with ventilatory movements of the abdomen serving as a telltale sign distinguishing sleep from other behaviors. Bouts of abdominal pulses broken by extended pauses (discontinuous ventilation) in an otherwise relatively immobile bee appears to indicate sleep. Can viewing the tips of abdomens consistently and predictably indicate what is happening with the rest of a bee’s body when inserted deep inside a honeycomb cell? To distinguish a sleeping bee from a bee maintaining cells, eating, or heating developing brood, we used a miniature observation hive with slices of honeycomb turned in cross-section, and filmed the exposed cells with an infrared-sensitive video camera and a thermal camera. Thermal imaging helped us identify heating bees, but simply observing ventilatory movements, as well as larger motions of the posterior tip of a bee’s abdomen was sufficient to noninvasively and predictably distinguish heating and sleeping inside comb cells. Neither behavior is associated with large motions of the abdomen, but heating demands continuous (vs. discontinuous) ventilatory pulsing. Among the four behaviors observed inside cells, sleeping constituted 16.9% of observations. Accuracy of identifying sleep when restricted to viewing only the tip of an abdomen was 86.6%, and heating was 73.0%. Monitoring abdominal movements of honey bees offers anyone with a view of honeycomb the ability to more fully monitor when and where behaviors of interest are exhibited in a bustling nest.

Managed honey bees as a radar for wild bee decline?

Wild and managed bees are essential for global food security and the maintenance of biodiversity. At present, the conservation of wild bees is hampered by a huge shortfall in knowledge about the trends and status of individual species mainly due to their large diversity and variation in life histories. In contrast, the managed Western honey bee Apis mellifera is one of the best studied and monitored insects in existence. Since similar drivers may be relevant for the decline of wild bees and losses of managed honey bees, this raises the possibility that monitoring of honey bees may help to detect threatened regions for wild bees, thereby fostering urgently required conservation measures. However, this possible relationship has not yet been explicitly tested for. Moreover, research currently focused on honey bees as a model species may yield important insights into wild insect susceptibility to stressors and vice versa. Here we use the bees of Europe as a model to show that managed honey bees are not suitable surrogates for detecting declines in wild bees. A direct comparison of the response of wild bees and honey bees to the same threats (nutritional deficiencies, parasites and pathogens, pesticides, and a changing climate) shows that, whilst some of their responses may be similar at the individual level, when considered at the reproductive level (individuals versus colonies), many of their responses diverge. These results reinforce the need for basic research into wild bee biology, the need for national monitoring schemes for wild bee populations, and the call for conservation actions tailored to the individual ecologies of wild bee species.

Microbiome Evolution: Having the Guts to Be Different

Metagenomic sequencing of the gut microbial communities of two closely related bee species, the Western honey bee (Apis mellifera) and the Eastern honey bee (Apis cerana), show that organisms with similar characteristics can harbor unexpected differences in their microbiomes.

Evaluating Spatiotemporal Resolution of Trace Element Concentrations and Pb Isotopic Compositions of Honeybees and Hive Products as Biomonitors for Urban Metal Distribution.

Assessing metal distributions in cities is an important aspect of urban environmental quality management. Western honeybees (Apis mellifera) and their products are biomonitors that can elucidate small‐scale metal distribution within a city. We compare range and variations in trace element (TE) concentrations and lead (Pb) isotopic compositions of honey, bee tissue, bee pollen, and propolis collected throughout Metro Vancouver (BC, Canada). Honey, bee, and bee pollen results have similar TE and isotopic trends; samples collected in urban and industrialized areas exhibit elevated concentrations of anthropogenically influenced TE (e.g., Pb, Zn, V, and Ti) and a less radiogenic Pb isotopic composition (i.e., lower 206Pb/207Pb and elevated 208Pb/206Pb) relative to their suburban and rural counterparts. For example, 206Pb/207Pb, 208Pb/206Pb in honey range from 1.126, 2.131 and 1.184, 2.063; extremes measured in honey from urban and suburban/rural areas, respectively. Except for propolis, measured and interpolated (kriged) results in all materials reflect the immediate zoning or land use setting near the hive, providing kilometer‐scale geospatial resolution, suitable for monitoring urban systems. Statistical analysis reveals that no systematic variations or intra‐ or inter‐annual trends exist in TE concentrations or Pb isotopic compositions, including among sampling and field methods (i.e., old vs. new hive equipment and honey from the brood nest box vs. honey super). The results of this systematic study using honeybees and hive products in Metro Vancouver provide a robust, current baseline for future comparison of local land use and environmental policy change.

Consumption, digestion, and utilization of beeswax by greater wax moths (Galleria mellonella L.)

Greater wax moths (GWM, Galleria mellonella L.) are important pests of Western honey bee (Apis mellifera L.) colonies. The larval moths feed on wax combs, cast honey bee larval skins, pollen, and some honey, leaving behind a destroyed comb containing moth silk and frass. We used standard protocols to determine how GWM larva consumption of wax comb impacts various food utilization and larval growth parameters. Five larval instars (3rd, 4th, 5th, 6th, and 7th) were assessed 24 hours after molting from the prior instar stage and 48 hours before molting to the next instar stage. The consumption rate (CR) of wax was lowest for 3rd instar larvae (17.5 ± 0.8 mg consumed/day, mean ± s.e.) and highest for 7th instar larvae (515.4 ± 22.7 mg/day). The relative growth rate (RGR) was lowest for 7th instar larvae (0.05 ± 0.01 mg/day) and highest in 3rd instar larvae (0.16 ± 0.04 mg/day). A similar trend (decrease in response with increase in larval age) was observed for conversion efficiency of ingested food (ECI), conversion efficiency of digested food (ECD), and approximate digestibility (AD). Third instar larvae had significantly higher ECIs, ECDs, and ADs than did all other larval instars. The data can be used to quantify the efficiency with which the GWM larvae assimilate food and utilize it for growth.

Varroa Destructor and the Sustainability of Apis Mellifera - an Overview

Varroa destructor is a parasitic mite that represents a major global threat for the Western honeybee Apis mellifera. This parasite managed to switch from its natural host the Eastern honeybee, A. cerana, and within a few decades, it spread among A. mellifera populations around the world. Today beekeepers are using a variety of different acaricides to keep the parasite population under control. However, for many of these substances, the parasite evolved resistance asking for the development of novel compounds. Hence the treatment is less suited as a sustainable tool in honeybee health; consequently, other alternative options are needed, and breeding of Varroa resistant honeybees have been suggested as a more sustainable solution. Here we reviewed the successful efforts and the apicultural procedures needed to be implemented to achieve resistant honeybees. We also describe the underlying resistance mechanisms and discuss the benefits of breeding within regional populations, considering the biodiversity aspects of A. mellifera.

Cuticular pheromones stimulate hygienic behavior in the honey bee (Apis mellifera)

The health of western honey bee (Apis mellifera) colonies is challenged by the parasitic mite Varroa destructor and the numerous harmful pathogens it vectors. Selective breeding for the naturally occurring social immune trait “hygienic behavior” has emerged as one sustainable approach to reducing the mites’ impact on honey bees. To expand our understanding of hygienic triggers and improve hygienic selection tools, we tested the hypothesis that the cuticular compounds (Z)-10-tritriacontene and (Z)-6-pentadecene, previously associated with unhealthy honey bee brood and/or brood targeted for hygiene, are triggers of honey bee hygienic behavior independent of brood health. In support of our hypothesis, application of synthetic (Z)-10-tritriacontene and (Z)-6-pentadecene onto brood and brood cell caps significantly increased hygienic behavior compared to application of similarly structured hydrocarbon controls (Z)-16-dotriacontene and (Z)-7-pentadecene. Furthermore, we demonstrate a significant positive correlation between colony-level hygienic responses to (Z)-10-tritriacontene and the traditional freeze-killed brood assay for selection of hygienic honey bee stocks. These results confirm biological activity of (Z)-6-pentadecene and reveal (Z)-10-tritriacontene as a novel hygiene trigger. They also support development of improved tools for honey bee colony monitoring and hygienic selection, and thus may accelerate development of honey bee stocks with greater resistance to Varroa and associated pathogens.

How to model honeybee population dynamics: stage structure and seasonality

Western honeybees (Apis Mellifera) serve extremely important roles in our ecosystem and economics as they are responsible for pollinating $ 215 billion dollars annually over the world. Unfortunately, honeybee population and their colonies have been declined dramatically. The purpose of this article is to explore how we should model honeybee population with age structure and validate the model using empirical data so that we can identify different factors that lead to the survival and healthy of the honeybee colony. Our theoretical study combined with simulations and data validation suggests that the proper age structure incorporated in the model and seasonality are important for modeling honeybee population. Specifically, our work implies that the model assuming that (1) the adult bees are survived from the egg population rather than the brood population; and (2) seasonality in the queen egg laying rate, give the better fit than other honeybee models. The related theoretical and numerical analysis of the most fit model indicate that (a) the survival of honeybee colonies requires a large queen egg-laying rate and smaller values of the other life history parameter values in addition to proper initial condition; (b) both brood and adult bee populations are increasing with respect to the increase in the egg-laying rate and the decreasing in other parameter values; and (c) seasonality may promote/suppress the survival of the honeybee colony.

The honeybee (Apis mellifera) developmental state shapes the genetic composition of the deformed wing virus-A quasispecies during serial transmission

The main biological threat to the western honeybee (Apis mellifera) is the parasitic mite Varroa destructor, largely because it vectors lethal epidemics of honeybee viruses that, in the absence of this mite, are relatively innocuous. The severe pathology is a direct consequence of excessive virus titres caused by this novel transmission route. However, little is known about how the virus adapts genetically during transmission and whether this influences the pathology. Here, we show that upon injection into honeybee pupae, the deformed wing virus type-A (DWV-A) quasispecies undergoes a rapid, extensive expansion of its sequence space, followed by strong negative selection towards a uniform, common shape by the time the pupae have completed their development, with no difference between symptomatic and asymptomatic adults in either DWV titre or genetic composition. This suggests that the physiological and molecular environment during pupal development has a strong, conservative influence on shaping the DWV-A quasispecies in emerging adults. There was furthermore no evidence of any progressive adaptation of the DWV-A quasispecies to serial intra-abdominal injection, simulating mite transmission, despite the generation of ample variation immediately following each transmission, suggesting that the virus either had already adapted to transmission by injection, or was unaffected by it.

Antibiotics in Apis mellifera Hemolymph

The western honey bee (Apis mellifera) is a large contributor to the food supply for humans. Over the past decades, there has been a decrease in bee colonies caused by multiple stress factors. A possible contributor to this decline is due to multiple infectious agents being introduced to the honey bees. In some hives, more than 90% of the dying bees contained a gram‐negative bacterium [1]. Honey bees’ immunities against diseases are not fully understood, so to better understand their immunity a method was devised to test for useful proteins and antibodies in Apis mellifera’s hemolymph. Our research begins by extracting the bee’s hemolymph while they are in a comatose state and freezing it. Next, the hemolymph is used in an aggravate solution and injected into mice over a period of several months several months for their bodies to start producing the unknown antibodies. After the immunization process is completed, the mice are sacrificed by extracting their spleen where it is homogenized and the supernatant is extracted and incubated into a media. The hybridoma cells are duplicated into monoclonal colonies and frozen in liquid nitrogen for further testing or continuously grown for immediate testing. The supernatant from the hybridoma cells is taken for analysis where multiple analytical tests are performed to identify which supernatants contain antibodies. Through analytical testing, we hope to discover antibodies that will help researchers better understand honey bee immunity to combat in the decline of honey bee colonies.

The Heat Shock Response in the Western Honey Bee (Apis mellifera) is Antiviral.

Honey bees (Apis mellifera) are an agriculturally important pollinator species that live in easily managed social groups (i.e., colonies). Unfortunately, annual losses of honey bee colonies in many parts of the world have reached unsustainable levels. Multiple abiotic and biotic stressors, including viruses, are associated with individual honey bee and colony mortality. Honey bees have evolved several antiviral defense mechanisms including conserved immune pathways (e.g., Toll, Imd, JAK/STAT) and dsRNA-triggered responses including RNA interference and a non-sequence specific dsRNA-mediated response. In addition, transcriptome analyses of virus-infected honey bees implicate an antiviral role of stress response pathways, including the heat shock response. Herein, we demonstrate that the heat shock response is antiviral in honey bees. Specifically, heat-shocked honey bees (i.e., 42 °C for 4 h) had reduced levels of the model virus, Sindbis-GFP, compared with bees maintained at a constant temperature. Virus-infection and/or heat shock resulted in differential expression of six heat shock protein encoding genes and three immune genes, many of which are positively correlated. The heat shock protein encoding and immune gene transcriptional responses observed in virus-infected bees were not completely recapitulated by administration of double stranded RNA (dsRNA), a virus-associated molecular pattern, indicating that additional virus–host interactions are involved in triggering antiviral stress response pathways.

Meta-analysis of honey bee neurogenomic response links Deformed wing virus type A to precocious behavioral maturation

Crop pollination by the western honey bee Apis mellifera is vital to agriculture but threatened by alarmingly high levels of colony mortality, especially in Europe and North America. Colony loss is due, in part, to the high viral loads of Deformed wing virus (DWV), transmitted by the ectoparasitic mite Varroa destructor, especially throughout the overwintering period of a honey bee colony. Covert DWV infection is commonplace and has been causally linked to precocious foraging, which itself has been linked to colony loss. Taking advantage of four brain transcriptome studies that unexpectedly revealed evidence of covert DWV-A infection, we set out to explore whether this effect is due to DWV-A mimicking naturally occurring changes in brain gene expression that are associated with behavioral maturation. Consistent with this hypothesis, we found that brain gene expression profiles of DWV-A infected bees resembled those of foragers, even in individuals that were much younger than typical foragers. In addition, brain transcriptional regulatory network analysis revealed a positive association between DWV-A infection and transcription factors previously associated with honey bee foraging behavior. Surprisingly, single-cell RNA-Sequencing implicated glia, not neurons, in this effect; there are relatively few glial cells in the insect brain and they are rarely associated with behavioral plasticity. Covert DWV-A infection also has been linked to impaired learning, which together with precocious foraging can lead to increased occurrence of infected bees from one colony mistakenly entering another colony, especially under crowded modern apiary conditions. These findings provide new insights into the mechanisms by which DWV-A affects honey bee health and colony survival.

Propolis Consumption Reduces Nosema ceranae Infection of European Honey Bees (Apis mellifera).

Nosema ceranae is a widespread obligate intracellular parasite of the ventriculus of many species of honey bee (Apis), including the Western honey bee Apis mellifera, in which it may lead to colony death. It can be controlled in A. mellifera by feeding the antibiotic fumagillin to a colony, though this product is toxic to humans and its use has now been banned in many countries, so in beekeeping, there exists a need for alternative and safe products effective against N. ceranae. Honeybees produce propolis from resinous substances collected from plants and use it to protect their nest from parasites and pathogens; propolis is thought to decrease the microbial load of the hive. We hypothesized that propolis might also reduce N. ceranae infection of individual bees and that they might consume propolis as a form of self-medication. To test these hypotheses, we evaluated the effects of an ethanolic extract of propolis administered orally on the longevity and spore load of experimentally N. ceranae-infected worker bees and also tested whether infected bees were more attracted to, and consumed a greater proportion of, a diet containing propolis in comparison to uninfected bees. Propolis extracts and ethanol (solvent control) increased the lifespan of N. ceranae-infected bees, but only propolis extract significantly reduced spore load. Our propolis extract primarily contained derivatives of caffeic acid, ferulic acid, ellagic acid and quercetin. Choice, scan sampling and food consumption tests did not reveal any preference of N. ceranae-infected bees for commercial candy containing propolis. Our research supports the hypothesis that propolis represents an effective and safe product to control N. ceranae but worker bees seem not to use it to self-medicate when infected with this pathogen.

Controlling small hive beetles, Aethina tumida, in western honey bee (Apis mellifera) colonies by trapping wandering beetle larvae

The small hive beetle (SHB, Aethina tumida) is an invasive honey bee pest. It has been introduced into many countries worldwide and it will continue to spread. The lifecycle of the SHB is divided between a feeding and reproduction phase inside honey bee colonies and a pupation phase in the soil, surrounding colonies. Once larvae have achieved their ideal weight, they leave the hive in search of suitable soil in which to pupate. Trapping larvae when they leave the hive could reduce the reproductive success of SHBs, as this would break their lifecycle. Therefore, we investigated the larvae containment rate of different trap designs. Dry and wet larvae were released into traps and left to wander for 12 h, after which we counted the larvae remaining in the trap. Similarly, we tested the permeability of different mesh sizes for dry and wet larvae. Finally, we investigated the speed dry larvae are capable of crawling, by recording the time it took them to crawl a known distance. Dry larvae were contained by all traps. While most designs were unable to contain wet larvae, a trap with walls of sandpaper was able to contain all larvae successfully. Larvae could not pass through a mesh size of 1 mm in dry or wet conditions. The mean wandering larvae speed observed was 0.42 cm/sc. We recommend the use of traps for wandering SHB larvae as a mitigative measure for new introductions and a control method for established populations.

Two routes of transmission for Nosema infections in a honeybee population model with polyethism and time-periodic parameters can lead to drastically different qualitative model behavior

Nosema ceranae is a widespread microsporidian parasite of the Western honeybee (Apis mellifera). We extend a previous mathematical model of the disease by including mass action infection as a second route of transmission. The underlying honeybee population model accounts for polyethism by considering hive and forager bees separately. It accounts for seasonal variations in honeybee biology by considering model parameters as time-periodic functions. The resulting model is too complex for an insightful rigorous analysis, wherefore we study it primarily with numerical techniques. Our results suggest that direct transmission alone can lead to chaotic behavior in the underlying model, but that this behavior is dampened or suppressed when both transmission routes are considered simultaneously.

Varroa mite evolution: a neglected aspect of worldwide bee collapses?

While ectoparasitic Varroa mites cause minimal damage to their co-evolved ancestral host, the eastern honey bee (Apis cerana), they devastate their novel host, the western honey bee (Apis mellifera). Over several decades, the host switch caused worldwide population collapses, threatening global food security. Varroa management strategies have focused on breeding bees for tolerance. But, can Varroa overcome these counter-adaptations in a classic coevolutionary arms race? Despite increasing evidence for Varroa genetic diversity and evolvability, this eventuality has largely been neglected. We therefore suggest a more holistic paradigm for studying this host-parasite interaction, one in which 'Varroa-tolerant' bee traits should be viewed as a shared phenotype resulting from Varroa and honey bee interaction.

Radio-Frequency Electromagnetic Field Exposure of Western Honey Bees

Radio-frequency electromagnetic fields (RF-EMFs) can be absorbed in all living organisms, including Western Honey Bees (Apis Mellifera). This is an ecologically and economically important global insect species that is continuously exposed to environmental RF-EMFs. This exposure is studied numerically and experimentally in this manuscript. To this aim, numerical simulations using honey bee models, obtained using micro-CT scanning, were implemented to determine RF absorbed power as a function of frequency in the 0.6 to 120 GHz range. Five different models of honey bees were obtained and simulated: two workers, a drone, a larva, and a queen. The simulations were combined with in-situ measurements of environmental RF-EMF exposure near beehives in Belgium in order to estimate realistic exposure and absorbed power values for honey bees. Our analysis shows that a relatively small shift of 10% of environmental incident power density from frequencies below 3 GHz to higher frequencies will lead to a relative increase in absorbed power of a factor higher than 3.

Dominant honeybee colony infestation by Varroa destructor (Acari: Varroidae) K haplotype in Japan

Varroa destructor Anderson and Trueman (Acari: Varroidae) are ectoparasitic mites found in the western honeybee Apis mellifera Linnaeus (Hymenoptera: Apidae). Varroa destructor is classified into two haplotypes, i.e., Korea (K) and Japan (J), based on mtDNA sequences. Among these, V. destructor K haplotype is possibly a more severe threat to A. mellifera colonies. Previous studies collected both V. destructor haplotypes from honeybee colonies in Japan. However, no detailed surveillance of infestation of Japanese apiaries by V. destructor or identification of their genetic structure has been conducted to date. We surveyed V. destructor at 15 different Japanese apiaries of A. mellifera. Varroa destructor was collected from 14 Japanese apiaries, and all mites were classified as V. destructor K haplotype. Varroa destructor infestation of the Japanese honeybee A. cerana japonica Radoszkawsi (Hymenoptera: Apidae) was also analyzed. Varroa destructor K haplotype was predominant in A. cerana colonies. Despite the different host species, all collected V. destructor K haplotype samples were classified into a single haplogroup, i.e., K1-1/K1-2. These results indicate that A. mellifera and A. cerana were infested by the same V. destructor haplogroup. This is the first report detailing a survey on V. destructor prevalence and haplogroups among Japanese apiaries.

Evaluating the Efficacy of Oxalic Acid Vaporization and Brood Interruption in Controlling the Honey Bee Pest Varroa destructor (Acari: Varroidae).

A successful Integrated Pest Management approach to Varroa destructor Anderson and Trueman control in managed colonies of western honey bees Apis mellifera Linnaeus (Hymenoptera: Apidae) must be an improvement over conventional control methods and include cost-effective treatments that can be readily employed by beekeepers. Herein, we tested the efficacy of oxalic acid (OA) vaporization and brood interruption as Varroa controls. Sixty experimental colonies were randomly assigned to one of six treatment groups with 10 colonies per group. The six treatments were: 1) OA applied once, 2) OA applied three times, 3) brood interruption, 4) OA applied once + brood interruption, 5) OA applied three times + brood interruption, and 6) no OA or brood interruption. The OA was applied via vaporization, with each application being 1 g OA applied through the hive entrance (label rate), on the bottom board. Brood interruption was accomplished by caging a colony's queen in a queen cage for a period of 24 d. An additional 10 colonies were treated with amitraz (Apivar - positive control). Varroa levels were estimated before, during, and after treatment applications using sticky boards left in colonies for 3 d. Our data suggest that queen caging to achieve brood interruption during the fall season can negatively impact colony strength and survival. We observed high colony mortality in some treatments, despite diligent colony management to alleviate the side effects of the treatments. Colonies treated with amitraz were healthier and had better survival than those treated with OA vaporization. In conclusion, OA and/or brood interruption did not provide sufficient Varroa control.