Colony Decline Research Articles

Secondary Metabolites Produced by Honey Bee-Associated Bacteria for Apiary Health: Potential Activity of Platynecine.

Secondary metabolites of bacteria associated with honey bees were evaluated as part of an investigation on their potentiality for apiary health. Low molecular weight compounds released into culture filtrates by the four bacterial isolates taken from surface of healthy honey bees were analyzed using time-of-flight mass spectrometry. Only one low molecular weight compound was found in the culture filtrate of each isolate. Bacillus thuringiensis, Bifidobacterium asteroides and Acetobacteraceae bacterium, released into culture filtrates platynecine, a pyrrolizidine alkaloid of plant origin, which, until now, had never been reported as produced by bacteria. Lactobacillus kunkeei produced a 3,5-dinitropyridine, of unknown biological action never associated so far to bacteria. The highest relative concentration of platynecine was detected in B. thuringiensis (100%), B. asteroides and A. bacterium showed a concentration above 50% and below 25% that concentration. An in vitro assay on the potential for controlling the parasitic mite Varroa destructor by the culture filtrates of the three platynecine-producing bacteria was performed. Varroa mite mortality was proportional to the platynecine relative concentration into culture filtrate. Although miticidal activity of B. thuringiensis might be associated to other toxic proteins produced by this species, B. asteroides toxicity toward V. destructor along with the other findings of this study support the hypothesis that platynecine plays a direct or an indirect role in controlling varroa. Findings of this study suggest that secondary metabolites released by honey bee-associated bacteria represent a source of natural compounds to be considered in the challenge for counteracting the colony decline.

In Vitro Assessment of Antimicrobial Potential of Ethanolic and Aqueous Extract of Against Some Highly Resistant Pathogens

Objective: To find out the antibacterial potential of ethanolic and aqueous roots extract of Phlomis umbrosa L. against both Gram positive and Gram negative isolates Methodology: Disk diffusion method according to Clinical Laboratory and Standards Institute (CLSI) standard was used to examine the in vitro antibacterial activity of P. umbrosa extract while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using broth dilution technique. Miles and Misra technique was also utilized to count the number of colonies CFU/mL of bacteria at different concentrations of extract. Results: All the studied strains showed a diverse range of vulnerability against both ethanolic and aqueous plant extract. Among all tested isolates, ethanolic extract of P. umbrosa showed highly significant activity against Gram positive isolates i.e. S. aureus (20.1 mm) and B. subtilis (22.9 mm) with least MIC (12.5 mg/mL) and MBC (12.5 mg/mL) as compared to Gram negative isolates. A progressive decline in bacterial colonies (CFU/mL) was observed in Miles and Misra technique. One way ANOVA followed by postHoc Tukey test showed the significant differences in antimicrobial activities of plant extract with two tested antibiotics i.e. Amoxicillin and Erythromycin (10 µg/disc) as positive control at p-value of 0.05. The antimicrobial activity of this plant exhibit may be due to the presence of such chemical constituents namely monoterpenoids and sesquiterpenoids compounds. Conclusion: It is concluded that roots ethanolic extract of P. umbrosa has a promising antibacterial potential so it can also be used as an alternative medicine to treat different infections for reducing bacterial resistance and side effects associated with antibiotics. 

Body mass, mercury exposure, biochemistry and untargeted metabolomics of incubating common eiders (Somateria mollissima) in three Baltic colonies

The Baltic/Wadden Sea Flyway of common eiders has declined over the past three decades. Multiple factors such as contaminant exposure, global warming, hunting, white-tailed eagle predation, decreased agricultural eutrophication and infectious diseases have been suggested to explain the decline. We collected information on body mass, mercury (Hg) concentration, biochemistry and untargeted metabolomics of incubating birds in two colonies in the Danish Straits (Hov Røn, n = 100; Agersø, n = 29) and in one colony in the Baltic proper (Christiansø, n = 23) to look into their metabolisms and energy balance. Body mass was available from early and late incubation for Hov Røn and Christiansø, showing a significant decline (25–30%) in both colonies with late body mass at Christiansø being the lowest. Whole blood concentrations of total mercury Hg were significantly higher in birds at Christiansø in the east compared to Hov Røn in the west. All birds in the three colonies had Hg concentrations in the range of ≤1.0 μg/g ww, which indicates that the risk of effects on reproduction is in the no to low risk category for wild birds. Among the biochemical measures, glucose, fructosamine, amylase, albumin and protein decreased significantly from early to late incubation at Hov Røn and Christiansø, reflecting long-term fastening as supported by the decline in body mass. Untargeted metabolomics performed on Christiansø eiders revealed presence of 8,433 plasma metabolites. Of these, 3,179 metabolites changed significantly (log2-fold change ≥1, p ≤ 0.05) from the early to late incubation. For example, smaller peptides and vitamin B2 (riboflavin) were significantly down-regulated while 11-deoxycorticosterone and palmitoylcarnitine were significantly upregulated. These results show that cumulative stress including fasting during incubation affect the eiders’ biochemical profile and energy metabolism and that this may be most pronounced for the Christiansø colony in the Baltic proper. This amplify the events of temperature increases and food web changes caused by global warming that eventually accelerate the loss in body weight. Future studies should examine the relationship between body condition, temperature and reproductive outcomes and include mapping of food web contaminant, energy and nutrient content to better understand, manage and conserve the populations.

Causas de mortalidad de colonias de Polistes dominula (Christ, 1791) (Hymenoptera, Vespidae) en zonas urbanas del suroeste de la Península Ibérica

De 2017 a 2018 se estudiaron diversas poblaciones de la avispa eusocial Polistes dominula (Christ, 1791) en tres municipios del suroeste de la península ibérica, con la finalidad de identificar las causas de mortalidad de sus colonias. Los resultados mostraron que la causa principal de mortalidad en las zonas de estudio fue la actividad antrópica (43,55 %). La segunda causa más relevante fue el abandono del nido (20,19 %). Únicamente 82 de 411 nidos (19,95 %) demostraron un declive natural de la colonia, tras la aparición de reproductores.

Lotmaria Passim As Third Parasite Gastrointestinal Tract of Honey Bees Living in Tree Trunk

Abstract Honey bees (Apis mellifera L.) inhabiting trees in forests are not managed by humans or treated for pathogens; therefore, many researchers and beekeepers believe that viral, bacterial, and parasitic diseases may lead to their decline. The aim of the study was to evaluate the prevalence of L. passim and Nosema spp. in feral colonies by real-time PCR. This study was performed on twenty-six samples of honey bees inhabiting tree trunks in north-eastern Poland. One sample consisted of sixty worker bee abdomens collected from hollow trees. Honey bees were sampled only from naturally colonized sites. Amplicons of the three evaluated pathogens were detected in twenty of the twenty-six tested samples. A significant correlation was observed between infection with three pathogens (N. apis, N. ceranae, L. passim) (r = 0.84) compared to infection with only two pathogens (N. apis and N. ceranae) (r = 0.49). N. ceranae was the predominant pathogen, but infections with various severity caused by L. passim were also noted in fourteen of the twenty-six tested samples. In view of the general scarcity of epidemiological data concerning coinfections with Nosema spp. and L. passim in honey bees in tree trunks in other countries, further research is needed to confirm the effect of concurrent pathogenic infections on the decline of bee colonies.

Neutral sterols in honey bee (Apis mellifera) feces

Nutrition is important in honey bee (Apis mellifera L.) colony decline. While the honey bee is incapable of converting dietary plant sterols to cholesterol, the sterol 24-methylenecholesterol has been previously shown to be selectively transferred from worker honey bees to developing brood in both laboratory and field studies. The importance of 24-methylenecholesterol to honey bee development and nutrition is unknown. This selective transfer suggests either (i) honey bees concentrate 24-methylenecholesterol in their tissues by selectively excreting other sterols in their feces (hypothesis 1), or (ii) some other metabolic/physiological mechanism exists to segregate/sequester 24-methylencholesterol for transfer to brood (hypothesis 2). The objective of this study was to determine if any C28 and C29 sterols other than 24-methylenecholesterol were selectively excreted in the feces by the honey bee (hypothesis 1), thereby concentrating the relative percentages of 24-methylenecholesterol in worker bee tissue, and thereby partially explaining the mechanism of selective sterol transfer in honey bees. We conducted the study by confining worker honey bees in a small cage with glass sides to facilitate the collection of honey bee feces. After four days, the neutral sterols were identified and the percentages of these sterols were determined from the pollen the honey bees presumably consumed prior to confinement, from the tissues of the confined worker bees, and from their feces. There was no apparent excessive excretion of other C28 and C29 phytosterols such as campesterol, sitosterol and isofucosterol and stigmasterol in honey bee feces, suggesting that hypothesis 2 (above) needs investigation.

Interactions Between Thiamethoxam and Deformed Wing Virus Can Drastically Impair Flight Behavior of Honey Bees.

Exposure to multiple stress factors is believed to contribute to honey bee colony decline. However, little is known about how co-exposure to stress factors can alter the survival and behavior of free-living honey bees in colony conditions. We therefore studied the potential interaction between a neonicotinoid pesticide, thiamethoxam, and a highly prevalent honey bee pathogen, Deformed wing virus (DWV). For this purpose, tagged bees were exposed to DWV by feeding or injection, and/or to field-relevant doses of thiamethoxam, then left in colonies equipped with optical bee counters to monitor flight activity. DWV loads and the expression of immune genes were quantified. A reduction in vitellogenin expression level was observed in DWV-injected bees and was associated with precocious onset of foraging. Combined exposure to DWV and thiamethoxam did not result in higher DWV loads compared to bees only exposed to DWV, but induced precocious foraging, increased the risk of not returning to the hive after the first flight, and decreased survival when compared to single stress exposures. We therefore provided the first evidence for deleterious interactions between DWV and thiamethoxam in natural conditions.

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.

A Reverse Genetics System for the Israeli Acute Paralysis Virus and Chronic Bee Paralysis Virus.

Honey bee viruses are associated with honey bee colony decline. Israeli acute paralysis virus (IAPV) is considered to have a strong impact on honey bee survival. Phylogenetic analysis of the viral genomes from several regions of the world showed that various IAPV lineages had substantial differences in virulence. Chronic bee paralysis virus (CBPV), another important honey bee virus, can induce two significantly different symptoms. However, the infection characteristics and pathogenesis of IAPV and CBPV have not been completely elucidated. Here, we constructed infectious clones of IAPV and CBPV using a universal vector to provide a basis for studying their replication and pathogenesis. Infectious IAPV and CBPV were rescued from molecular clones of IAPV and CBPV genomes, respectively, that induced typical paralysis symptoms. The replication levels and expression proteins of IAPV and CBPV in progeny virus production were confirmed by qPCR and Western blot. Our results will allow further dissection of the role of each gene in the context of viral infection while helping to study viral pathogenesis and develop antiviral drugs using reverse genetics systems.

Electron Paramagnetic Resonance Imaging of Melanin in Honey Bee

Honey bees play a crucial role in the nature by pollinating wild flowers. Over the past years, there has been an increasing concern regarding the honey bee colony decline. Pesticides or environmental effects targeting the biochemistry of insect chitin and cuticle coating may be in part responsible for honey bee pathologies. We here propose the use of electron paramagnetic resonance imaging (EPRI) as a tool to image the melanin-chitin complexes as part of the exoskeleton of the honey bee. EPRI at 9.65 GHz was applied on intact freeze-dried bees. The imaging data were collected on the melanin peak. High-resolution images revealed that this compound is extensively distributed in the periphery of the animal, data consistent with the localization in the cuticle of the bee. While EPR of melanin has been so far explored in the context of melanoma characterization, it may offer new opportunities in research on honey bees and other insects.

The Contribution of Managed Honey Bees to Crop Pollination, Food Security, and Economic Stability: Case of Ethiopia

This paper reviews the role and economic importance of the pollination service by honey bees (Apis mellifera) to agricultural crops and food security in the Ethiopian context. Honey bees provide pollination services that are crucial for sexual reproduction and improving the quality and quantity of many agricultural crops. From the significant 53 crops cultivated in Ethiopia, 33 (62.2%) of them are dependent on biological pollinators. Besides this, honey bees play a vital economic role, and their contribution to pollination service in agriculture crops is around 0.815 billion dollars in Ethiopia. Nevertheless, this contribution is unnoticed by Ethiopian farmers. Pollination by honey bee plays an essential role in human nutrition and supplies food security, income in households, and ecosystem services. Declines in insect pollinators, including honey bees across the world, have raised concerns about the supply of pollination services to agriculture, and it is because one-third of agriculture productions depend upon pollination, mainly by honey bees. Among the several factors responsible for the decline of honey bee colonies, improper pesticide application, and climate change are the elements and make them at risk. The potential adverse effects of pollinator declines include direct economic losses incurred by reduced crop yields as well as broader impacts on the agricultural activity because of lower productivity in the ecosystems. Through promoting and the use of honey bee pollination service as agricultural development packages, it is possible to improve honey bee production and crop yield in Ethiopia.

Historical records and increasing trends of Caribbean Flamingos (Phoenicopterus ruber) on Margarita Island, Venezuela

ABSTRACTThe Caribbean Flamingo (Phoenicopterus ruber) has been a species of conservation concern since the 1960s because of its regional population decline and loss of breeding colonies. In the last two decades, there have been reports of increasing population trends in the Caribbean. The aim of this work is to document the historic population status of flamingos on Margarita Island, Venezuela, and to present an account of their recovery since 2006. In the first half of the twentieth century, flamingos were present on Margarita Island in one location (La Restinga lagoon) in variable numbers (100–800); however, in the 1980s and 1990s, they almost disappeared from the island. In 2006, a group of nine was recorded. During the following years, the population increased in number and expanded eastward on the island. Today, the population size range 1 600–2 000 individuals, are present regularly in at least eight lagoons, and two breeding colonies have been reported. Several threats are still present in the island that can revert the positive population trend. The recovery of the population in Margarita Island is a consequence of successful regional conservation efforts and the maintenance of wetlands with appropriate conditions for the species, particularly in protected areas.

Occurrence and Molecular Phylogeny of Honey Bee Viruses in Vespids.

Since the discovery that honey bee viruses play a role in colony decline, researchers have made major breakthroughs in understanding viral pathology and infection processes in honey bees. Work on virus transmission patterns and virus vectors, such as the mite Varroa destructor, has prompted intense efforts to manage honey bee health. However, little is known about the occurrence of honey bee viruses in bee predators, such as vespids. In this study, we characterized the occurrence of 11 honey bee viruses in five vespid species and one wasp from four provinces in China and two vespid species from four locations in France. The results showed that all the species from China carried certain honey bee viruses, notably Apis mellifera filamentous virus (AmFV), Deformed wing virus (DWV), and Israeli acute paralysis virus (IAPV); furthermore, in some vespid colonies, more than three different viruses were identified. In France, DWV was the most common virus; Sacbrood virus (SBV) and Black queen cell virus (BQCV) were observed in one and two samples, respectively. Phylogenetic analyses of IAPV and BQCV sequences indicated that most of the IAPV sequences belonged to a single group, while the BQCV sequences belonged to several groups. Additionally, our study is the first to detect Lake Sinai virus (LSV) in a hornet from China. Our findings can guide further research into the origin and transmission of honey bee viruses in Vespidae, a taxon of ecological, and potentially epidemiological, relevance.

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.

High mortality of adult female Magellanic penguins by gillnet fisheries in southern Brazil

Abstract Bycatch in gillnet fisheries is one of the main threats to several penguin species. Magellanic penguins (Spheniscus magellanicus) are caught by gillnets during their wintering in southern Brazil. However, current information is based only on a small number of sets observed during a single fishing trip. This study assesses bycatch rates of bottom and drift gillnets operating in southern Brazil, and describes the sex and age classes of individuals captured. In 80 bottom gillnet sets, 33 penguins were captured (85% adults), 14 were sexed of which 13 were females. In 41 drift gillnet sets, four penguins were captured, three of which were juveniles. The mean bycatch rates, measured as number of penguins km−2 of net and number of penguins km−2 h−1, were significantly higher for the drift gillnets. Despite the lower bycatch rates, owing to the higher fishing effort in terms of number of boats, net length, net area, soak time and fishing season, the magnitude of penguin bycatch in the bottom gillnet fishery cannot be ignored. Despite based on small sample size, the predominance of adult and female Magellanic penguins as bycatch in gillnet fisheries in southern Brazil agrees with previous studies suggesting that females displace further north than males. In addition, such evidence contributes to the male‐biased sex ratio in breeding grounds, and the long‐term decline of major Patagonian colonies owing to higher female mortality during winter.

Результати щорічного моніторингу втрат бджолиних колоній в Україні: зимівля 2017-2018 рр

Decline of honey bee colonies remains a global problem. It may affect catastrophically both ecosystems and the global economy. Here we present the results of the fourth year of a research project on bee colony losses in Ukraine over winter 2017-2018, conducted in the framework of international monitoring coordinated by the non-profit honey bee research association COLOSS. Overall winter loss rate and the mortality rate over winter 2017-2018 were significantly lower compared to the previous year: overall winter loss rate – 11.3% (95 % СІ 10.0-12.6); mortality rate – 6.7% (95 % СІ 5.8-7.7); rate of colony loss due to unsolvable queen problems – 2.1% (95 % СІ 1.6-2.7) and due to natural disasters – 2.4% (95 % СІ 2.0-3.0). Likewise previous years, the highest losses were observed in small operations (with 50 or fewer colonies). The highest overall loss rate was observed in the Steppe zone, with the highest both mortality rate and losses due to natural disasters compared to the other physiographic zones of Ukraine. Minimum mortality was recorded from deciduous forests 5.6 % (95 % CI 4.4-7.2) and the Ukrainian Carpathians 5.5 % (95 % CI 4.2-7.2). Winter losses related to queen problems varied greatly with a minimum in the Forest-Steppe zone 0.71 % (95 % CI 0.3-1.5). 83.3% of beekeepers treated their colonies against Varroa. The r-rank correlation analysis identified two potential risk factors (no or only a few dead bees in or in front of the empty hive; dead workers in cells and no food present) which revealed a weak positive correlation with both mortality rate and the rate of losses due to unsolvable queen problems.

Multi-sensor platform for real time measurements of honey bee hive parameters

Honey bees (Apis mellifera L.) are well-known insects that have positive effects on the environment and on the human life. They are so important that the decline of honey bee colonies happened in the last years has triggered an increasing interest for their safeguard. In this context, the proposed work aims at developing a multi-sensor platform to monitor the beehives’ conditions in real time, based on the measurement of sounds emitted by the bees, temperature, humidity, CO2, weight inside the beehive, and weather conditions outside the hive. In this paper, a detailed description of the multi-sensor platform is reported and its application in a real scenario is presented.

Scientific Advances in Controlling Nosema ceranae (Microsporidia) Infections in Honey Bees (Apis mellifera).

Honey bees (Apis mellifera) are agriculturally important pollinators that have been recently at risk to severe colony losses. A variety of parasites and pathogens have been linked to colony decline, including the microsporidian parasite Nosema ceranae. While fumagillin has been used to control nosemosis in managed honey bee colonies for decades, research shows that this antibiotic poses a toxic threat and that its efficacy against N. ceranae is uncertain. There is certainly a demand for a new veterinary medication to treat honey bee colonies infected with N. ceranae. In this review, recent scientific advances in controlling N. ceranae infections in honey bees are summarized.

Collapse of a protector species drives secondary endangerment in waterbird communities

Interactions and dependence between species can transmit the effects of species declines within and between trophic levels, resulting in secondary endangerments and, in some cases, extinctions. Many mixed-species avian breeding aggregations commonly have a protector species whose aggressive nest defense is used by other species to defend their nests. Disappearance of the protector species may have population demographic consequences on the dependent species. Aggressive nest defense behavior of small colonial gulls, such as the black-headed gull (Chroicocephalus ridibundus), is used by many waterbird species to gain protection against predators. We used data from 15 local waterbird communities in Finland to study long-term changes and dynamics of breeding numbers of other waterbirds as a response to long-term changes and dynamics of black-headed gull colonies. We found that breeding numbers of many species tracked long-term changes in the size of black-headed gull colonies. This was true even after controlling for a common trend in the size of the black-headed gull colony and the breeding numbers of the other species. The trend-controlled positive temporal association with black-headed gull was relatively stronger in species that nest in similar habitats of a lake as the black-headed gull, and in species that have a more critical conservation status due to drastic population decline. Our results suggest that the overall decline of black-headed gull colonies has resulted in secondary endangerment of many other species in waterbird communities.

Improved Pollination Efficiency and Reduced Honey Bee Colony Decline in Greenhouses by Allowing Access to the Outside During Part of the Day

Although honey bees are efficient pollinators of many crops cultivated in greenhouses, it is difficult to maintain colony strength and consequently pollination efficiency. Many bees die under greenhouse conditions and the colonies rapidly weaken. We examined the effect of adaptations to the hive entrance that allowed control of whether and when bees had access to the outside environment to see how it would affect pollination efficiency and colony condition in greenhouses with flowering cucumber (Cucumis sativus) plants in comparison with colonies that remained constantly inside the greenhouse, previously left in a dark environment or not. We recorded the type and period of visitation to the cucumber flowers, numbers of honey bees entering and leaving the two entrance hives and the effect of this type of management on the quantity of brood and food. Fiveframe Langstroth “nucleus” colonies were equipped with two 30 square centimeter entrances and two 3.0 cm diameter circular openings. Allowing the bees to make visits outside the greenhouse in early morning with redirection of bees into the greenhouse at 8.30 a.m. did not reduce visitation to cucumber flowers in the greenhouse. Maintaining colonies in the greenhouse reduced brood area and food stores. These losses were significantly reduced in colonies that had access outside the greenhouse during the early morning. Another advantage of alternating access to the inside and the outside of the greenhouse was that there was less possibility of interactions between bees and people working on the crop, and also pesticides application could be made without directly affecting foraging bees.