Adult Bees Research Articles

Effect of sub-lethal doses of thiamethoxam on hypopharyngeal glands of Apis mellifera Linnaeus

Honey bees provide key ecosystem services i.e., pollination but are functioning under various biotic and abiotic stresses. Among various stresses, thiamethoxam has been criticized worldwide. Since no scientific study on its sub-lethal effects on honey bees has been conducted in India, the present work was carried out at the Department of Entomology, Punjab Agricultural University, Ludhiana for two seasons during 2017-19. The median lethal dietary dose (LDD50) of thiamethoxam upon chronically feeding the sub-lethal doses for 10 days for a group of adult Apis mellifera bees (age 10 days) was 0.421 ng bee−1 day−1. At this level, the reduction in the area of an acinus of the hypopharyngeal gland was significant i.e., 36.62 and 37.92 percent over control during spring and winter seasons, respectively. The adverse impact of thiamethoxam on hypopharyngeal glands will be limiting the development and productivity of the honey bee colonies.

Impact of Neem Oil on Developmental Stages of Honey Bee Apis mellifera L.

Toxicity of neem oil on developmental stages of Apis mellifera L. was evaluated by applying three concentrations within the marked comb cells with micropipette as single (applied only once) and multiple exposures (at one day interval up to capping of cells) on different age groups of larvae (1-2, 3-4 and 5-6 days). Results revealed that maximum survival was observed in controls (both negative and positive) and at par with 0.05% (T1) and 0.1 % (T2) concentrations. Minimum survival of larval stage was found in 1% (T3). Same trend was also observed in emerged pupae (CD=17.9) and in mortality of adult bees (CD=15.3). Significant difference in the survival of larval (p<0.05), emerged pupae (p<0.05) and mortality of adult (p<0.05) honey bees was found within stages originating from treated larvae. Both in single or multiple doses, it was found that larvae treated at 1-2 days age group was significantly affected as compared to other stages.

Consumption of Supplemental Spring Protein Feeds by Western Honey Bee (Hymenoptera: Apidae) Colonies: Effects on Colony Growth and Pollination Potential.

Adequate nutrition is required to support productive honey bee colonies, therefore beekeepers supplement colonies with additional protein at targeted time points. We tested the effects of commercially available protein feeds in spring, in advance of colonies being used for hybrid canola pollination. The feed treatments across the three-year study included the following patty types: Global 15% pollen, Global 0% pollen, Bee Pollen-Ate, FeedBee, and Healthy Bees, as well as an unsupplemented control in year two of the study only. The amount of feed consumed varied among colonies, treatments, date, and year. Similarly, there were also differences in feed efficiency (bees reared per gram of feed consumed), likely due to the relative availability of external forage sources to supplement the feed provided. Unsupplemented colonies were able to rear less brood, and subsequently had fewer adult bees than supplemented colonies, in an apiary where pollen was not abundant. Differences in consumption among treatments often failed to translate in to differences in amount of brood reared or subsequent adult population. All the protein feed treatments contained all ten amino acids essential to honey bees, however lysine and arginine were below the optimal proportion required for growth in all patties except the FeedBee patty. The amount of protein and amount and types of sugars and fats in the products also varied among product type and batch. The results of this study demonstrate a benefit to supplementary spring protein feeding to increase honey bee colony populations in advance of a summer pollination market.

Ion chromatography coupled to Q-Orbitrap for the analysis of formic and oxalic acid in beehive matrices: a field study

There is an increasing concern about the use of synthetic acaricides to fight the ectoparasitic mite Varroa destructor. Natural products such as formic acid (FA) and oxalic acid (OA) have emerged as a possible alternative control strategy. However, given the difficulty of analysing these highly polar compounds and the lack of robust and reliable methods, there are very few studies of the concentration and distribution of these natural acaricides in the beehive compartments. We present a reliable and simple analytical methodology, based on sample extraction with modified quick polar pesticide (QuPPe) methods followed by ion chromatography coupled to a quadrupole Orbitrap mass analyser for the analysis of FA and OA in honeybees, honey, beeswax, and beebread. The developed methods have been used in a field study for the evaluation of the presence and distribution of FA and OA in the beehive products, as well as in adult bees and bee brood samples, before, during, and up to 3 months after the application of the treatments by the beekeeper. Beebread and honey samples presented the highest concentration levels of OA and FA, respectively, mainly due to their natural presence. As expected, the organic acids showed low persistence in wax after the treatments. The natural acaricides were found in adult and developing bees at concentration levels below the reported LD50 in all the cases; however, residue levels of OA in larvae during the treatment application were very close to the reported LD50.Graphical abstract

The phylogenetic analysis of RNA-dependent RNA polymerase gene of chronic bee paralysis virus in Turkey

Chronic bee paralysis virus (CBPV) is a major contributor to global bee colony losses. However, among the RNA viruses infecting honeybees, CBPV is still not classified. In this study, samples of asymptomatic adult honey bees were randomly collected from 45 apiaries in three provinces (Burdur, Antalya, and Isparta) in Turkey. Five of the 45 samples were determined to be positive by reverse transcription polymerase chain reaction (RT-PCR). In addition, three positive samples from Burdur, Isparta, and Antalya were confirmed by sequencing. We constructed a phylogenetic tree that was divided into five main groups based on the RNA-dependent RNA polymerase gene region. The Turkish strains TUR/BUR/CBPV1, TUR/ISPT/CBPV2, and TUR/ANT/CBPV3 and the Turkish strains from obtained previous studies formed a different cluster. The sequence homology results of a phylogenetic analysis showed that the Turkish strains shared 97-98.9% of their nucleotide identity and had 96.9-99% similarity rates with each other. The strains obtained in this study and the Turkish strains detected in previous studies were also 81-84.6% similar to European, Chinese, and Uruguay strains. This research underlines the presence of CBPV in apparently healthy Turkish bee colonies and the remarkable differences in Turkish CBPV strains. Further investigation is needed to identify the molecular characterization, complete genome sequence, and pathogenesis of Turkish CBPV strains.

Traces of a neonicotinoid pesticide stimulate different honey bee colony activities, but do not increase colony size or longevity

How neonicotinoid contamination affects honey bees remains controversial. Studies have yielded contradictory results, and few have examined effects on colony development. Here we report the results of a comprehensive five-year study of the effects of the neonicotinoid imidacloprid on honey bee colonies. Colonies fed 5 ng/g (ppb) imidacloprid in sugar syrup showed increased brood production, lower temperature variability, higher CO2 production and had more foragers compared to control colonies fed unadulterated syrup, but treatment did not affect adult bee numbers or average hive temperatures, and did not increase food stores, daily food acquisition or colony survivorship. These results suggest that imidacloprid contamination increased colony metabolism without improving colony productivity, and helps explain why some studies have reported no, or even positive, effects of neonicotinoids. Effect sizes were generally small but that could be attributed at least in part to variability in uncontrolled factors such as weather. We provide an explanation for the diverse effects of pesticide contamination on honey bees, and an improved understanding of how colonies are impacted.

Nosemosis Prevention and Control

Nosemosis is a serious microsporidian disease of adult European honey bees caused by the spore-forming unicellular fungi Nosema apis and Nosema ceranae. In this paper we describe the currently known techniques for nosemosis prevention and control including Good Beekeeping Practices (GBPs) and biosecurity measures (BMBs). Topics such as queen renewal, nosema-resistant bees and hygienic and control methods are described. Strong efforts are currently provided to find more a sustainable solution than the use of antibiotics. So far, it seems that the best way to approach nosemosis is given by an “integrated pest management strategy”, which foresees the contemporary application of different, specific GBPs and BMBs.

Tragedy of the commons in Melipona bees revisited.

Melipona stingless bees display a paradoxical overproduction of queens, which are later eliminated by nest-mate workers. Mechanistically, it was suggested that the monoterpenoid geraniol deposited into newly provisioned cells by adult bees would cause larvae to develop into queens in Melipona beecheii. This system could be evolutionarily stable if many of these new queens were to leave the nest and parasitize other genetically unrelated colonies nearby, as was shown to occur in a congeneric species. Here, we use microsatellite markers to test whether queen overproduction could be a strategy by which adult workers control the caste fate of the developing larvae to export copies of their own genes to the rest of the population via queen parasitism in M. beecheii. In addition, we re-examined whether artificially increasing the levels of geraniol indeed caused larvae to develop as queens rather than workers. Contrary to our prediction, we found no evidence for queen parasitism in M. beecheii and observed no effect of geraniol on the rearing of new queens. Together, these results support the original 'tragedy of the commons' hypothesis for queen overproduction in Melipona bees, where individual larvae selfishly bias their development towards the queen pathway according to their best evolutionary interests.

Assessing Repeated Oxalic Acid Vaporization in Honey Bee (Hymenoptera: Apidae) Colonies for Control of the Ectoparasitic Mite Varroa destructor.

The American beekeeping industry continually experiences colony mortality with annual losses as high as 43%. A leading cause of this is the exotic, ectoparasitic mite, Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae). Integrated Pest Management (IPM) options are used to keep mite populations from reaching lethal levels, however, due to resistance and/or the lack of suitable treatment options, novel controls for reducing mites are warranted. Oxalic acid for controlling V. destructor has become a popular treatment regimen among commercial and backyard beekeepers. Applying vaporized oxalic acid inside a honey bee hive is a legal application method in the U.S., and results in the death of exposed mites. However, if mites are in the reproductive stage and therefore under the protective wax capping, oxalic acid is ineffective. One popular method of applying oxalic is vaporizing multiple times over several weeks to try and circumvent the problem of mites hiding in brood cells. By comparing against control colonies, we tested oxalic acid vaporization in colonies treated with seven applications separated by 5 d (35 d total). We tested in apiaries in Georgia and Alabama during 2019 and 2020, totaling 99 colonies. We found that adult honey bees Linnaeus (Hymenoptera: Apidae), and developing brood experienced no adverse impacts from the oxalic vaporization regime. However, we did not find evidence that frequent periodic application of oxalic during brood-rearing periods is capable of bringing V. destructor populations below treatment thresholds.

Determination of the Optimal Maturation Temperature for Adult Honey Bee Toxicity Testing

Determination of the Optimal Maturation Temperature for Adult Honey Bee Toxicity Testing

Cuticle melanization and the expression of immune-related genes in the honeybee Apis mellifera (Hymenoptera: Apidae) adult workers.

The global decline of bee populations has several factors, including pathogens, which need overcome the insect defenses such as the physical barriers, the body cuticle and peritrophic matrix (primary defenses), as well as the secondary defenses with antimicrobial peptides (AMPs) and the enzyme lysozyme. The regulation of immune defenses according to the infection risks raises questions about the immunity of social bees due to their exposition to different pathogens pressures during the adult lifespan and tasks performed. This study evaluated the primary (body cuticle melanization, peritrophic matrix and cpr14 expression) and secondary (AMPs and lysozyme expression) defenses of the honeybee Apis mellifera workers according to the age and tasks. The expression of malvolio was used to detect precocious forage tasks outside the colony. Forager workers have higher amount of cuticular melanization in the body cuticle than nurse, but not when the age effect is retired, indicating the gradual acquisition of this compound in the integument of adult bees. The relative value of chitin in the peritrophic matrix and cpr14 mRNA are similar in all bees evaluated, suggesting that these components of primary defenses do not change according to the task and age. Differential expression of genes for AMPs in workers performing different tasks, within the same age group, indicates that the behavior stimulates expression of genes related to secondary immune defense. The expression of malvolio gene, accelerating the change in workers behavior, and those related to immune defense suggest the investment in secondary defense mechanisms when the primary defense of the body cuticle is not yet completed.

TECHNOLOGY OF KEEPING BEE WITH THE PURPOSE OF INCREASING ACTIVITY AND HYGIENIC BEHAVIOR

The study examined the technology of keeping bees in order to increase the activity of hygienic behavior as a factor of natural resistance. The aim of the work was to study the activity of hygienic behavior by determining differences in bees of different breeds, zoned on the territory of Ukraine, in different families of the same breed in different apiaries, healthy and with signs of infectious diseases, as well as studying the specificity of the behavior of adult bees in cleaning the body from parasites (mites Varroa) and recognition and removal of infectioned pupae from brood cells. There was presented the correlation of the activity of hygienic behavior on the breed characteristics and strength of the bee colony. It was determined that the Ukrainian steppe breed of bees had a demonstrative activity of hygienic behavior and was more resistant to infection by ectoparasites and pathogens compared to the Carpathian breed. The difference in the duration of complete cleaning of the cells in bee colonies of the Ukrainian steppe and Carpathian breeds was 4±1 hours on average. There was explored the study of the hygienic behavior of honey bees before the recognition and removal of infectioned pupae from the sealed working brood within the same breed. Bee activity lasted for 6 days, the intensity was maximum in the first three days: on average, 64,5% of damaged pupae were removed. However, the reactions of bees were nonspecific in relation to the parasite. After 6 days no significant differences were found between mechanically damaged cells (47,7%) and cells infectioned by the Varroa mite (48.3%). The activity of bees was manifested during six days, the intensity of grooming and hygienic behavior was maximum during the first three days: on average, 77,4% of Varroa females were thrown from the bees' bodies and 64.5% of damaged pupae were removed from the cells. However, the reactions of the bees were not specific to the parasite, the corresponding cleaning movements were performed by the bees in the control experiments as well.

The effects of beta-cypermethrin, chlorbenzuron, chlorothalonil, and pendimethalin on Apis mellifera ligustica and Apis cerana cerana larvae reared in vitro.

Declines in bee populations and diversity have drawn international attention. The long-term use of chemical pesticides has affected bee behavior and physiology. This study aimed to investigate the effects of chronic exposure to four commonly used chemical pesticides (beta-cypermethrin, chlorbenzuron, chlorothalonil and pendimethalin) on the growth of Apis mellifera ligustica and Apis cerana cerana larvae reared in vitro. Pesticide type and concentration were the main factors affecting honeybee fitness. Beta-cypermethrin and chlorbenzuron had chronic toxic effects on bee larvae. They reduced the fitness of A. m. ligustica and A. c. cerana even at low doses of 323.5ng g-1 for beta-cypermethrin and 62.6ng g-1 for chlorbenzuron in bee bread. The effects were positively associated with the dietary amounts of pesticides. By contrast, chlorothalonil and pendimethalin exposure did not affect bee larvae despite changes in enzyme activities. Caution is still needed with chlorothalonil, which led to a decrease in harvest adult bee numbers at a high dose (6937.2ng g-1 ). Furthermore, a difference in pesticide resistance was observed, suggesting that A. m. ligustica may tolerate toxic effects better than A. c. cerana. This study sheds new light on chronic toxicity in bee larvae exposed to residues in bee bread. The results could guide the scientific and rational use of chemical pesticides to reduce the potential risks to A. m. ligustica and A. c. cerana. © 2021 Society of Chemical Industry.

Physiological and biochemical response of the solitary bee Osmia bicornis exposed to three insecticide-based agrochemicals

The physiological and biochemical stress induced by pesticides need to be addressed in economically and ecologically important non-Apis solitary bees, particularly at lower than field-applied concentrations. Thus, the aim of the present study was to analyse the physiological and biochemical changes in female adult Osmia bicornis bees upon continuous oral exposure to three insecticide-based agrochemicals – i.e. Dursban 480 EC (active ingredient - a.i. chlorpyrifos), Sherpa 100 EC (a.i. cypermethrin), and Mospilan 20 SP (a.i. acetamiprid), in a toxicokinetic manner (feeding with either insecticide-contaminated food or uncontaminated food (controls) for 8 d in the contamination phase followed by 8 d of decontamination (i.e. feeding with uncontaminated food)). All three tested agrochemicals altered the energetic budget of bees by the deprivation of energy derived from lipids and carbohydrates (but not proteins) and/or a decrease in respiration based metabolic rate (energy consumption) compared to the controls. The activities of acetylcholinesterase and glutathione-S-transferase enzymes were not altered by insecticides at tested concentrations. These results show that chronic exposure to at least some pesticides even at relatively low concentrations may cause severe physiological disruptions that could potentially be damaging for the solitary bees.

Bacterial microbiota in Nannotrigona testaceicornis (Lepeletier, 1836) colonies

Stingless bees are found in tropical and subtropical regions, being social and with greater species diversity. For the colony to be healthy and have good productivity, bees make mutualistic interactions with specific microorganisms. This study was carried out to analyze the bacterial community present in colonies of Nannotrigona testaceicornis. The experiments were performed by methods dependent on cultivation, quantification, morphotintorial analyzes and chemical tests. The bacteria isolated from the adult stingless bees, pupae, larvae, propolis, stored pollen and honey samples from the six colonies, were divided into five groups according to their main characteristics: Coryneform, Lactobacillaceae, Sporulated Bacilli, Micrococcacea and Streptococcacea. The highest bacterial load was found in propolis followed by the adult stingless bee; in addition, common bacterial populations were found among the samples. This work, the microbiota associated with stingless bee colony N. testaceicornis, contributes to a better understanding of the symbiotic relationships between social bees and microorganisms.

In Vitro Rearing Changes Social Task Performance and Physiology in Honeybees.

Simple SummaryThe rearing of honeybee larvae in the laboratory is an important tool for studying the effects of plant protection products or pathogens on developing and adult bees, yet how rearing under artificial conditions affects the later social behavior and physiology of the honeybees is mostly unknown. We, here, show that honeybees reared in the laboratory generally had a lower probability for performing nursing or foraging tasks compared to bees reared under natural conditions in bee colonies. Nursing behavior itself appeared normal in in vitro honeybees. In contrast, bees reared in the laboratory foraged for a shorter period in life and performed fewer trips compared to bees reared in colonies. In addition, in vitro honeybees did not display the typical increase in juvenile hormone titer, which goes hand-in-hand with the initiation of foraging in colony-reared bees.In vitro rearing of honeybee larvae is an established method that enables exact control and monitoring of developmental factors and allows controlled application of pesticides or pathogens. However, only a few studies have investigated how the rearing method itself affects the behavior of the resulting adult honeybees. We raised honeybees in vitro according to a standardized protocol: marking the emerging honeybees individually and inserting them into established colonies. Subsequently, we investigated the behavioral performance of nurse bees and foragers and quantified the physiological factors underlying the social organization. Adult honeybees raised in vitro differed from naturally reared honeybees in their probability of performing social tasks. Further, in vitro-reared bees foraged for a shorter duration in their life and performed fewer foraging trips. Nursing behavior appeared to be unaffected by rearing condition. Weight was also unaffected by rearing condition. Interestingly, juvenile hormone titers, which normally increase strongly around the time when a honeybee becomes a forager, were significantly lower in three- and four-week-old in vitro bees. The effects of the rearing environment on individual sucrose responsiveness and lipid levels were rather minor. These data suggest that larval rearing conditions can affect the task performance and physiology of adult bees despite equal weight, pointing to an important role of the colony environment for these factors. Our observations of behavior and metabolic pathways offer important novel insight into how the rearing environment affects adult honeybees.

Live and dead qPCR detection demonstrates that feeding of Nosema ceranae results in infection in the honey bee but not the bumble bee

As the honey bee and bumble bee may suffer from the same or related microbial pathogens, cross contamination from commercially reared Bombus spp. to honey bees and wild bumble bees and vice versa is a major concern. Honey bee-collected pollen to feed commercially reared Bombus spp. is a potential risk. Nosema spp. is a fungal pathogen in bees. In this study, we developed new quantitative detection tools based on the detection of RNA using a TaqMan-based RT-qPCR for Nosema ceranae and Nosema apis, with extraction controls based on the actin gene of honey bees and bumble bees, respectively. These tools were subsequently applied to study the epidemiology of N. ceranae, a main disease in honey bees. We screened gamma radiation and cold treatment sterilisation for their efficacy to kill N. ceranae spores fed in sugar water and in pollen to honey bees and bumble bees, respectively. N. ceranae infection in adult bumble bees was checked. Spores passing the inter-alimentary track were found but no infection was observed. N. ceranae spores were fed to honey bees. Their presence and multiplication were demonstrated, showing the spores were both viable and infectious. Our results indicate that N. ceranae found in honey bees cannot infect commercially reared bumble bees (Bombus terrestris) and, that gamma radiation effectively kills N. ceranae. The highly specific and sensitive molecular assays developed, were exploited to detect N. ceranae in pollen and faeces, which would allow more comprehensive epidemiological studies on this important pathogen.

АДАПТОГЕННОЕ ДЕЙСТВИЕ ПРЕПАРАТОВ АПИСИЛ И ТОС-БИО НА МЕДОНОСНУЮ ПЧЕЛУ В УСЛОВИЯХ ГИПЕРТЕРМИИ

The temperature factor has a huge impact on bees and their development. In a complex complex of adaptation, not only a perfect system of collective thermoregulation of the family is important, but also such individual adaptations as resistance to freezing and tolerance to high temperatures. The deviation of the ambient temperature from the optimal one increases the energy consumption of bees for the regulation of the microclimate in the family. This means that it enhances metabolic processes, which affects the state of the body and the life expectancy of insects. In addition, sometimes the use of high temperatures is a necessary condition for their maintenance, for example, in the fight against the parasite of the bee mite varroa. At the same time, the effect of high temperatures can have a negative effect not only on the mite, but also on the bees. In laboratory conditions, the effect of Apisil and TOS-BIO preparations containing 9-oxoand 10-hydroxy-2E-decenoic acids as a base - the most important components of the «queen substance» and royal jelly of the honey bee Apis mellifera L., respectively - on the survival rate and biochemical parameters was studied. adult worker bees exposed to extremely high (50oC) temperatures. The dynamics of the activity of phenoloxidase and catalase as biochemical indicators of the stress response of a honey bee under high temperature load has been studied. It was shown that the insects' resistance to hyperthermia increased with the content of these preparations in the feed. Experimental results indicate that under extreme (50oC) temperature conditions Apisil and TOS-BIO preparations have an adaptogenic effect on worker bees, increasing their resistance to hyperthermia. At the same time, changes in the initial level and dynamics of biochemical parameters indicate that these compositions in the most economical way contribute to the restructuring of metabolism in the mode of optimal functioning, which affects the level of changes in enzyme activity (with less pronounced changes in activity). and also on the survival rate of bees at the end of the experiment.

Evaluating the strength of western honey bee (Apis mellifera L.) colonies fed pollen substitutes over winter

AbstractWestern honey bees (Apis mellifera L.) need good nutrition to combat multiple stressors. Beekeepers often feed artificial protein diets (i.e. pollen substitutes) when their colonies lack natural pollen resources. However, it is unclear whether pollen substitutes improve honey bee colony strength and health during pollen dearths and when no pollen stores are available, as can occur during late fall and winter. We fed 56 managed honey bee colonies one of two commercially available pollen substitutes (AP23® and MegaBee®) or no diet (control) over the late fall and winter in north‐central Florida under a simulated pollen dearth and when the colonies lacked pollen stores. We determined the change in adult bee mass and the final brood mass of each colony throughout the feeding period. On average, colonies in each of the three treatment groups experienced a loss in total adult bee mass during the feeding period, which is typical of colonies during winter. Nevertheless, colonies that received AP23 lost significantly less adult bee mass than did control colonies, with colonies that received MegaBee having a loss in adult bee mass intermediate to those of the other two groups. The AP23 and MegaBee colonies had significantly greater brood mass than did control colonies. When accounting for total change in colony biomass (adult bee mass + brood mass), the AP23 group lost significantly less mass than did control colonies, with the MegaBee colonies having a mass loss intermediate to those of the other two groups. Colonies consumed significantly more AP23 than they consumed MegaBee. Collectively, our data suggest that it may be beneficial for beekeepers in warm climates to feed pollen substitutes to stressed honey bee colonies over winter to lessen the loss in total colony biomass.

Methoprene, a juvenile hormone analogue, modifies maturation and emergence in overwintering Osmia rufa L. adults

The development of methods aimed at activation of imagos at any point of wintering provides a compelling potential avenue to utilize bees for pollination of greenhouse crops during autumn, winter, and early spring. In this study, we tested methoprene, a juvenile hormone (JH) analogue as a chemical stimulant to end a diapause of Osmia rufa L. and enable bee activation and emergence under experimental conditions. The application of methoprene significantly reduced the emergence time of adult bees in winter months as compared to vehicle (acetone) and negative controls. Bees treated with methoprene started to emerge 3–6 days earlier than bees from acetone and control groups and finished emergence 2–6 days earlier too. Statistically significant differences were observed between methoprene and controls groups of male and female in all tested incubation periods. It was also observed that the effects of methoprene were significantly more effective in female specimens during the first 2 months of winter. Moreover, in females, methoprene improved reproductive traits such as an increase in the size of terminal oocytes. Similarly, in males, methoprene treatment resulted in a significant increase in a seminal vesicle size and dynamic elevation of spermatozoa number. Taken together, our results indicate that methoprene may play an important role in the termination of diapause, bee activation, and emergence.