European Honey Bee Apis Mellifera Research Articles

Varroa destructor: how does it harm Apis mellifera honey bees and what can be done about it?

Since its migration from the Asian honey bee (Apis cerana) to the European honey bee (Apis mellifera), the ectoparasitic mite Varroa destructor has emerged as a major issue for beekeeping worldwide. Due to a short history of coevolution, the host–parasite relationship between A. mellifera and V. destructor is unbalanced, with honey bees suffering infestation effects at the individual, colony and population levels. Several control solutions have been developed to tackle the colony and production losses due to Varroa, but the burden caused by the mite in combination with other biotic and abiotic factors continues to increase, weakening the beekeeping industry. In this synthetic review, we highlight the main advances made between 2015 and 2020 on V. destructor biology and its impact on the health of the honey bee, A. mellifera. We also describe the main control solutions that are currently available to fight the mite and place a special focus on new methodological developments, which point to integrated pest management strategies for the control of Varroa in honey bee colonies.

Effect of cold narcosis on foraging behavior of European honey bees (Apis mellifera ligustica) tracked using a radio-frequency identification (RFID) system

Radio-frequency identification (RFID) is both a commonly used method and a promising tool for investigating the foraging activities of bees. To prevent loss of electronic tags from individual bees, they must be immobilized long enough for adhesives to dry, but because narcosis can negatively affect bee health and behaviors, a very brief narcosis period is recommended. The present study assessed the impact of 30 min of cold narcosis, compared with carbon dioxide or no narcosis, on foraging activities using RFID monitoring. From each of three hives, 8 to 10 bees were placed in each of three narcosis treatments (n = 85), then tagged and monitored for homing success, activity after returning to the hive, and duration of flights outside the hive. Bees showed no significant differences in homing success and flight duration between cold narcosis treatment and the control (no narcosis), whereas bees narcotized by carbon dioxide showed significantly lower homing success and shorter flight duration than control bees. We conclude that for observing bee foraging behaviors using RFID systems, the effects of cold narcosis on ice for 30 min on foraging behaviors are acceptable, and cold narcosis is more practical for tagging many bees at once than physical immobilization using plunger cages.

Microbial Profile of the Ventriculum of Honey Bee (Apis mellifera ligustica Spinola, 1806) Fed with Veterinary Drugs, Dietary Supplements and Non-Protein Amino Acids.

The effects of veterinary drugs, dietary supplements and non-protein amino acids on the European honey bee (Apis mellifera ligustica Spinola, 1806) ventriculum microbial profile were investigated. Total viable aerobic bacteria, Enterobacteriaceae, staphylococci, Escherichia coli, lactic acid bacteria, Pseudomonas spp., aerobic bacterial endospores and Enterococcus spp. were determined using a culture-based method. Two veterinary drugs (Varromed® and Api-Bioxal®), two commercial dietary supplements (ApiHerb® and ApiGo®) and two non-protein amino acids (GABA and beta-alanine) were administered for one week to honey bee foragers reared in laboratory cages. After one week, E. coli and Staphylococcus spp. were significantly affected by the veterinary drugs (p < 0.001). Furthermore, dietary supplements and non-protein amino acids induced significant changes in Staphylococcus spp., E. coli and Pseudomonas spp. (p < 0.001). In conclusion, the results of this investigation showed that the administration of the veterinary drugs, dietary supplements and non-protein amino acids tested, affected the ventriculum microbiological profile of Apis mellifera ligustica.

Anti-fungal properties and mechanisms of melittin.

Many fungal diseases remain poorly addressed by public health authorities, despite posing a substantial threat to humans, animals, and plants. More worryingly, few classes of anti-fungals have been developed to combat fungal infections thus far. These medications also have certain drawbacks in terms of toxicity, spectrum of activity, and pharmacokinetic properties. Hence, there is a dire need for discovery of novel anti-fungal agents. Melittin, the main constituent in the venom of European honeybee Apis mellifera, has attracted considerable attention among researchers owing to its potential therapeutic applications. To our knowledge, there has been no review pertinent to anti-fungal properties of melittin, prompting us to synopsize the results of experimental investigations with a special emphasis upon underlying mechanisms. In this respect, melittin inhibits a broad spectrum of fungal genera including Aspergillus, Botrytis, Candida, Colletotrichum, Fusarium, Malassezia, Neurospora, Penicillium, Saccharomyces, Trichoderma, Trichophyton, and Trichosporon. Melittin hinders fungal growth by several mechanisms such as membrane permeabilization, apoptosis induction by reactive oxygen species-mediated mitochondria/caspase-dependent pathway, inhibition of (1,3)-β-D-glucan synthase, and alterations in fungal gene expression. Overall, melittin will definitely open up new avenues for various biomedical applications, from medicine to agriculture. KEYPOINTS: • Venom-derived peptides have potential for development of anti-microbial agents. • Many fungal pathogens are susceptible to melittin at micromolar concentrations. • Melittin possesses multi-target mechanism of action against fungal cells.

Avocado crops as a floral resource for native bees of Chile

BackgroundChile is the second largest avocado producer in the world. However, there have been few studies on interactions between native bees and avocado pollination in a Chilean environment. The flowering period of avocado is very sensitive to temperature fluctuations and so environmental conditions, particularly cool temperatures, can have a strong influence on its floral behaviour. Thus, we aimed to determine whether temperature also influences bee visitation rates to avocado flowers or if this was due to the number of available flowers. Moreover, we proposed to verify the attractiveness of avocado flowers to native bees and compare flower handling time and type of floral resource collected between managed and native bees.MethodsAn avocado orchard of “Hass” cultivar located in the Mediterranean region of Chile was studied during the flowering season of 2016. The frequency of exotic and native bee species in flowers, floral phenology, and environmental temperature were analysed, and the foraging behaviours of exotic and native bee species in avocado flowers compared.ResultsFive Chilean native and two exotic species were recorded visiting avocado flowers at the studied orchard. The bees generally sought nectar rather than pollen. The European honeybee (Apis mellifera) was the most frequent flower visitor, followed by the native species Colletes cyanescens and Cadeguala occidentalis. There was a strong positive correlation between temperature and number of visits, but no significant correlation between number of open flowers and number of visits.ConclusionsNative Chilean bees visited avocado flowers and some of them were frequent floral visitors. They generally sought for nectar rather than pollen and were as fast as honeybees handling avocado flowers. The environmental temperature plays a key role in the frequency of bees in avocado flowers. The warmer weather is related to the higher number of bees visits to avocado flowers.

The invasive hornet Vespa velutina affects pollination of a wild plant through changes in abundance and behaviour of floral visitors

The Asian hornet (Vespa velutina) is a keen predator of honeybees and other insects. Its success as invasive species threatens the stability of ecosystem services provided by them, such as pollination of wild plants and crops. In this study we analyse their impact as hunters of flower visitors on plant pollination, by studying the hunting behaviour of V. velutina in flower surroundings, the effect of V. velutina hunting on the floral visiting behaviour by insects and its impact on the amount of conspecific pollen deposited on the stigmas of Mentha suaveolens, a native and common herb to southern and western Europe. We made observations and video-recordings in blooming patches with and without the presence of V. velutina and quantified the deposition of conspecific pollen on stigmas in those same patches. Asian hornets were frequent and successful hunters of flower visitors of Mentha suaveolens, inducing changes in the foraging behaviour of several groups of pollinators. The patch visitation rate of European honeybees (Apis mellifera), the flower visitation rate of small hymenopterans and the flower visitation time of bumblebees (Bombus sp.) and syrphids was significantly reduced in patches with presence of the predator. As a consequence, the quantity of conspecific pollen on stigmas of the studied native plant decreased in patches with V. velutina. In this study we demonstrate the negative impact of the invasive hornet V. velutina on pollination services in invaded areas as a consequence of their hunting of pollinators in flower patches.

PVC nest boxes are less at risk of occupancy by feral honey bees than timber nest boxes and natural hollows

SummaryFeral European Honey Bee (Apis mellifera) has been identified as a potential nest competitor for Australian hollow nesting species, but few studies have investigated the impact of feral honey bee competition on Threatened species. Our study used data from Glossy Black‐cockatoo (Calyptorhynchus lathami halmaturinus) nests on Kangaroo Island, monitored and managed over an 11‐year period, and found 12% of nests became occupied by feral honey bees during that period. Our results indicate that feral honey bees were less likely to occupy nest boxes made of PVC (5%) compared with wooden nest boxes (24%) or natural hollows in Eucalyptus trees (14%). The removal of feral honey bee hives from nests is a priority for long‐term conservation of glossy black‐cockatoos on Kangaroo Island. We recommend that PVC nest boxes are chosen for future nesting habitat restoration, due to the more frequent use of wooden nest boxes by feral honey bees.

Range expansion of the tracheal mite Acarapis woodi (Acari: Tarsonemidae) among Japanese honey bee, Apis cerana japonica, in Japan

Acarapis woodi, a parasitic mite of honey bees, was first detected in Japan in 2010. Infestation was mostly observed in the Japanese honey bee (Apis cerana japonica) and was rare in the European honey bee (Apis mellifera). By 2014, the mites had spread throughout central and eastern Japan. In the current study, we investigated the subsequent expansion of the mite to western Japan. Our research revealed that the mites were distributed across most of Japan by 2018, except for Wakayama and Kochi prefectures. Many small remote islands more than 20km away from mainland Japan are still free of A. woodi, but bees on some of these islands were infested. About 40% of colonies of the Japanese honey bee in Japan were infested by the mites, and average mite prevalence of the infested colonies was about 50% during the 6-year study. There was no trend of decline in the infested colony proportion or in the mite prevalence. In addition, the observation of Japanese honey bee colonies by hobby beekeepers for two signs of mite infestation, K-wing and crawling bees, was an effective means for estimating infestation by tracheal mites.

Evidence of Competition between Honey Bees and Hylaeus anthracinus (Hymenoptera: Colletidae), an Endangered Hawaiian Yellow-Faced Bee

European honey bees (Apis mellifera) were first introduced to the Hawaiian Islands in the late 1800s, and are now ubiquitous across the state in both managed and feral colonies. Though they play an important role in pollination services for native plants and agricultural crops, the competitive impacts they may have on native bees are not well understood. We assessed bee interactions on the preferred floral resources of Hylaeus anthracinus at the Ka Iwi State Scenic Shoreline on O‘ahu, including Heliotropium foertherianum, Scaevola taccada, and Myoporum sandwicense. Bee visitation frequency and duration were documented and analyzed in one-hour increments from 08:00–13:00 totaling 90 hours of video recordings of the focal plants. Honey bee visitation frequency to H. foertherianum peaked at 11:00, and corresponded with a significant reduction in H. anthracinus visitation that resulted in a bimodal activity distribution for H. anthracinus. Feeding duration of H. anthracinus was significantly reduced when visiting H. foertherianum flowers following a honey bee, but unchanged when visiting after conspecifics. Honey bee feeding duration was unaltered by the species of the previous visitor, indicating that deterrence of H. anthracinus to flowers may not be the result of nectar exploitation. S. taccada and M. sandwicense received low overall bee visitation, prohibiting further analyses. We conclude that the presence of honey bees on a preferred foraging resource results in a temporal niche partitioning of H. anthracinus indicative of interference competition, possibly the result of interspecific chemical cues. Future honey bee management considerations are discussed.

Screening of Differentially Expressed Microsporidia Genes from Nosema ceranae Infected Honey Bees by Suppression Subtractive Hybridization.

The microsporidium Nosema ceranae is a high prevalent parasite of the European honey bee (Apis mellifera). This parasite is spreading across the world into its novel host. The developmental process, and some mechanisms of N. ceranae-infected honey bees, has been studied thoroughly; however, few studies have been carried out in the mechanism of gene expression in N. ceranae during the infection process. We therefore performed the suppressive subtractive hybridization (SSH) approach to investigate the candidate genes of N. ceranae during its infection process. All 96 clones of infected (forward) and non-infected (reverse) library were dipped onto the membrane for hybridization. A total of 112 differentially expressed sequence tags (ESTs) had been sequenced. For the host responses, 20% of ESTs (13 ESTs, 10 genes, and 1 non-coding RNA) from the forward library and 93.6% of ESTs (44 ESTs, 28 genes) from the reverse library were identified as differentially expressed genes (DEGs) of the hosts. A high percentage of DEGs involved in catalytic activity and metabolic processes revealed that the host gene expression change after N. ceranae infection might lead to an unbalance of physiological mechanism. Among the ESTs from the forward library, 75.4% ESTs (49 ESTs belonged to 24 genes) were identified as N. ceranae genes. Out of 24 N. ceranae genes, nine DEGs were subject to real-time quantitative reverse transcription PCR (real-time qRT-PCR) for validation. The results indicated that these genes were highly expressed during N. ceranae infection. Among nine N. ceranae genes, one N. ceranae gene (AAJ76_1600052943) showed the highest expression level after infection. These identified differentially expressed genes from this SSH could provide information about the pathological effects of N. ceranae. Validation of nine up-regulated N. ceranae genes reveal high potential for the detection of early nosemosis in the field and provide insight for further applications.

Surprising differences in the respiratory protein of insects: A spectroscopic study of haemoglobin from the European honeybee and the malaria mosquito

Only recently it was discovered that haemoglobin (Hb) belongs to the standard gene repertoire of insects, although their tracheal system is used for respiration. A classical oxygen-carrying function of Hb is only obvious for hexapods living in hypoxic environments. In other insect species, including the common fruit fly Drosophila melanogaster, the physiological role of Hb is yet unclear. Here, we study recombinant haemoglobin from the European honeybee Apis mellifera (Ame) and the malaria mosquito Anopheles gambiae (Aga). Spectroscopic evidence shows that both proteins can be classified as hexacoordinate Hbs with a strong affinity for the distal histidine. AgaHb1 is proposed to play a role in oxygen transport or sensing based on its multimeric state, slow autoxidation, and small but significant amount of five-coordinated haem in the deoxy ferrous form. AmeHb appears to behave more like vertebrate neuroglobin with a complex function given its diversified distribution in the genome.

The buzz around spatial resolving power and contrast sensitivity in the honeybee, Apis mellifera

Most animals rely on vision to perform a range of behavioural tasks and variations in the anatomy and physiology of the eye likely reflect differences in habitat and life history. Moreover, eye design represents a balance between often conflicting requirements for gathering different forms of visual information. The trade-off between spatial resolving power and contrast sensitivity is common to all visual systems, and European honeybees (Apis mellifera) present an important opportunity to better understand this trade-off. Vision has been studied extensively in A. mellifera as it is vital for foraging, navigation and communication. Consequently, spatial resolving power and contrast sensitivity in A. mellifera have been measured using several methodologies; however, there is considerable variation in estimates between methodologies. We assess pattern electroretinography (pERG) as a new method for assessing the trade-off between visual spatial and contrast information in A.mellifera. pERG has the benefit of measuring spatial contrast sensitivity from higher order visual processing neurons in the eye. Spatial resolving power of A.mellifera estimated from pERG was 0.54 cycles per degree (cpd), and contrast sensitivity was 16.9. pERG estimates of contrast sensitivity were comparable to previous behavioural studies. Estimates of spatial resolving power reflected anatomical estimates in the frontal region of the eye, which corresponds to the region stimulated by pERG. Apis mellifera has similar spatial contrast sensitivity to other hymenopteran insects with similar facet diameter (Myrmecia ant species). Our results support the idea that eye anatomy has a substantial effect on spatial contrast sensitivity in compound eyes.

The miticide thymol in combination with trace levels of the neonicotinoid imidacloprid reduces visual learning performance in honey bees (Apis mellifera)

Despite growing concerns over the impacts of agricultural pesticides on honey bee health, miticides (a group of pesticides used within hives to kill bee parasites) have received little attention. We know very little about how miticides might affect bee cognition, particularly in interaction with other known stressors, such as crop insecticides. Visual learning is essential for foraging bees to find their way to flowers, recognize them, and fly back to the nest. Using a standardized aversive visual conditioning assay, we tested how field exposure to three pesticides affects visual learning in European honey bees (Apis mellifera). Our pesticides were two common miticides, thymol in the commercial formulation Apiguard® and tau-fluvalinate in the formulation Apistan® and one neonicotinoid, imidacloprid. We found no effect of miticides alone, nor of field-relevant doses of imidacloprid alone, but bees exposed to both thymol and imidacloprid showed reduced performance in the visual learning assay.

Understanding the Effects of Sublethal Pesticide Exposure on Honey Bees: A Role for Probiotics as Mediators of Environmental Stress

Managed populations of the European honey bee (Apis mellifera) support the production of a global food supply. This important role in modern agriculture has rendered honey bees vulnerable to the noxious effects of anthropogenic stressors such as pesticides. Although the deleterious outcomes of lethal pesticide exposure on honey bee health and performance are apparent, the ominous role of sublethal pesticide exposure is an emerging concern as well. Here, we use a data harvesting approach to better understand the toxicological effects of pesticide exposure across the honey bee life cycle. Through compiling adult- and larval-specific median lethal dose (LD50) values from 93 published data sources, LD50 estimates for insecticides, herbicides, acaricides, and fungicides are highly variable across studies, especially for herbicides and fungicides, which are underrepresented in the meta-data set. Alongside major discrepancies in these reported values, further examination of the compiled data suggested that LD50 may not be an ideal metric for honey bee risk assessment. We also discuss how sublethal effects of pesticide exposure, which are not typically measured in LD50 studies, can diminish honey bee reproduction, immunity, cognition, and overall physiological functioning, leading to suboptimal honey bee performance and population reduction. In consideration of actionable solutions to mitigate the effects of sublethal pesticide exposure, we have identified the potential for probiotic supplementation as a promising strategy that can be easily incorporated alongside current agricultural infrastructure and apicultural management practices. Probiotic supplementation is regularly employed in apiculture but the potential for evidence-based targeted approaches has not yet been fully explored within a formal toxicological context. We discuss the benefits, practical considerations, and limitations for the use and delivery of probiotics to hives. Ultimately, by subverting the sublethal effects of pesticides we can help improve the long-term survival of these critical pollinators.

Incidence and predation rate of hornet (Vespa spp.) on European honeybee (Apis mellifera L.) apiary at mid-hill areas of Lalitpur district, Nepal

Predatory hornets are considered as one of the major constraints to beekeeping industry. Therefore, its incidence and predation rate was studied throughout the year at two locations- rural and forest areas of mid-hill in Laliptur district during 2016/017 to 2017/018. Observation was made on the number of hornet and honey bee captured by hornet in three different times of the day for three continuous minutes every fortnightly on five honeybee colonies. During the study period, major hornet species captured around the honeybee apiary at both locations were, Vespa velutina Lepeletier, Vespa basalis Smith, Vespa tropica (Linnaeus) and Vespa mandarina Smith. The hornet incidence varied significantly between the years and locations along with different observation dates. Their incidence and predation rates were low in early spring and summer that gradually increased with the highest peak in October and November in both locations. The maximum predation was on mid-November (62.07%) and early-November (53.49%) at rural and forest locations, respectively during 2016/017. In 2017/018, the highest predation was on early-November (70.27%) at rural area while it was in mid-November (58.62%) in the apiaries near the forest area. The population of hornet was considerably higher at forest areas and their incidence around the honeybee apiaries were negatively correlated with rainfall. Hence, assessment of the temporal and spatial population variations and predation rates along with weather parameters is helpful in to develop sustainable management plans of the hornet in apiary.

Complete mitochondrial DNA sequence of the parasitic honey bee mite Varroa destructor (Mesostigmata: Varroidae)

Varroa destructor is a parasite mite of the eastern honey bee Apis cerana, which is native to Asia. The European honey bee Apis mellifera was imported to Asia from Europe and the USA for apiculture in the 19th century. In a short period of time, V. destructor parasitized the artificially introduced honey bees. Varroa destructor was estimated to have spread around the world with A. mellifera when it was exported from Asia to locations worldwide about 50 years ago. The mitochondrial DNA of the parasitic honey bee mite V. destructor was analyzed using next-generation sequencing. The complete mitochondrial genome of V. destructor was identified as a 16,476-bp circular molecule containing 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and one AT-rich control region. The heavy strand was predicted to have nine PCGs and 13 tRNA genes, whereas the light strand was predicted to contain four PCGs, nine tRNA genes, and two rRNA genes. All PCGs began with ATA as the start codon, except COIII and CytB, which had ATG as the start codon. Stop codons were of two types: TAA for eight genes and TAG for five genes. Molecular phylogenetic analysis revealed that V. destructor from Japan was genetically distant from that of France. A high base substitution rate of 2.82% was also confirmed between the complete mitochondrial DNA sequences of V. destructor from Japan and the USA, suggesting that one Varroa mite strain found in the USA is not from Japan.

Biology and Management of Varroa destructor (Mesostigmata: Varroidae) in Apis mellifera (Hymenoptera: Apidae) Colonies

Abstract Varroa mite (Varroa destructor Anderson and Trueman) infestation of European honey bee (Apis mellifera L.) colonies has been a growing cause of international concern among beekeepers throughout the last 50 yr. Varroa destructor spread from the Asian honey bee (Apis cerana Fabricius [Hymenoptera: Apidae]) to A. mellifera populations in Europe in the 1970s, and subsequently traveled to the Americas. In addition to causing damage through feeding upon lipids of larval and adult bees, V. destructor also facilitates the spread of several viruses, with deformed wing virus being most prevalent. Several sampling methods have been developed for estimating infestation levels of A. mellifera colonies, and acaricide treatments have been implemented. However, overuse of synthetic acaricides in the past has led to widespread acaricide resistant V. destructor populations. The application of Integrated Pest Management (IPM) techniques is a more recent development in V. destructor control and is suggested to be more effective than only using pesticides, thereby posing fewer threats to A. mellifera colonies. When using IPM methods, informed management decisions are made based upon sampling, and cultural and mechanical controls are implemented prior to use of acaricide treatments. If acaricides are deemed necessary, they are rotated based on their mode of action, thus avoiding V. destructor resistance development.

Acute thiamethoxam toxicity in honeybees is not enhanced by common fungicide and herbicide and lacks stress-induced changes in mRNA splicing

Securing food supply for a growing population is a major challenge and heavily relies on the use of agrochemicals to maximize crop yield. It is increasingly recognized, that some neonicotinoid insecticides have a negative impact on non-target organisms, including important pollinators such as the European honeybee Apis mellifera. Toxicity of neonicotinoids may be enhanced through simultaneous exposure with additional pesticides, which could help explain, in part, the global decline of honeybee colonies. Here we examined whether exposure effects of the neonicotinoid thiamethoxam on bee viability are enhanced by the commonly used fungicide carbendazim and the herbicide glyphosate. We also analysed alternative splicing changes upon pesticide exposure in the honeybee. In particular, we examined transcripts of three genes: (i) the stress sensor gene X box binding protein-1 (Xbp1), (ii) the Down Syndrome Cell Adhesion Molecule (Dscam) gene and iii) the embryonic lethal/abnormal visual system (elav) gene, which are important for neuronal function. Our results showed that acute thiamethoxam exposure is not enhanced by carbendazim, nor glyphosate. Toxicity of the compounds did not trigger stress-induced, alternative splicing in the analysed mRNAs, thereby leaving dormant a cellular response pathway to these man-made environmental perturbations.

Ancestral hymenopteran queen pheromones do not share the broad phylogenetic repressive effects of honeybee queen mandibular pheromone

Queen pheromones effect the reproductive division of labour, a defining feature of eusociality. Reproductive division of labour ensures that one, or a small number of, females are responsible for the majority of reproduction within a colony. Much work on the evolution and function of these pheromones has focussed on Queen Mandibular Pheromone (QMP) which is produced by the Western or European honeybee (Apis mellifera). QMP has phylogenetically broad effects, repressing reproduction in a variety of arthropods, including those distantly related to the honeybee such as the fruit fly Drosophila melanogaster. QMP is highly derived and has little chemical similarity to the majority of hymenopteran queen pheromones which are derived from cuticular hydrocarbons. This raises the question of whether the phylogenetically widespread repression of reproduction by QMP also occurs with more basal saturated hydrocarbon-based queen-pheromones. Using D. melanogaster we show that saturated hydrocarbons are incapable of repressing reproduction, unlike QMP. We also show no interaction between the four saturated hydrocarbons tested or between the saturated hydrocarbons and QMP, implying that there is no conservation in the mechanism of detection or action between these compounds. We propose that the phylogenetically broad reproductive repression seen in response to QMP is not a feature of all queen pheromones, but unique to QMP itself, which has implications for our understanding of how queen pheromones act and evolve.

Detection of nosemosis in European honeybees (Apis mellifera) on honeybees farm at Kanchanaburi, Thailand

This study was aimed to the detection of Nosema in European honeybees at Kanchanaburi Province and Identify species of Nosema by Polymerase Chain Reaction technique. The ventriculus of bees was individually checked to verify the presence of Nosema spores under light microscope. The number of spores per bee were quantify on a haemocytometer for infectivity. It was studied for three periods of the year. The first period was studied between October 2015 to January 2016, the second period from February to May 2016 and the third period from June to September 2016. The results showed that the highest infection rate in June-September 2019 was 100 and the lowest infection rate was 40 in October 2015 and January 2019. The average number of Nosema spores infection level in an individual was infectivity. The highest infectivity was 2.47x106 spores/bee in February to May 2016 and the lowest infectivity was 0.04x106 spores/bee in October 2015 to January 2016. Nosema ceranae was found in this study by Polymerase Chain Reaction technique.