Honey Bee Population Decline Research Articles

Detecting varroosis using a gas sensor system as a way to face the environmental threat

Colony Collapse Disorder (CCD) is an environmental threat on a global scale due to the irreplaceable role of bees in crop pollination. Varroa destructor (V.d.), a parasite that attacks honeybee colonies, is one of the primary causes of honey bee population decline and the most serious threat to the beekeeping sector. This work demonstrates the possibility of quantitatively determining bee colony infestation by V.d. using gas sensing. The results are based on analysing the experimental data acquired for eighteen bee colonies in field conditions. Their infestation rate was in the 0 to 24.76% range. The experimental data consisted of measurements of beehive air with a semiconductor gas sensor array and the results of bee colony V.d. infestation assessment using a flotation method. The two kinds of data were collected in parallel. Partial Least Square regression was applied to identify the relationship between the highly multivariate measurement data provided by the gas sensor array and the V.d. infestation rate. The quality of the developed quantitative models was very high, as demonstrated by the coefficient of determination exceeding R2 = 0.99. Moreover, the prediction error was <0.6% for V.d. infestation rate predictions based on the measurement data that was unknown to the model. The presented work has considerable novelty. To our knowledge, the ability to determine the V.d. infestation rate of bee colony quantitatively based on beehive air measurements using a semiconductor gas sensor array has not been previously demonstrated.

Nest Modification Protects Immature Stages of the Japanese Orchard Bee (Osmia cornifrons) from Invasion of a Cleptoparasitic Mite Pest.

Osmia cornifrons (Radoszkowski) (Hymenoptera: Megachilidae) is an effective orchard pollinator. Considering the honey bee population decline in recent years, the conservation and propagation of O. cornifrons as an alternative managed pollinator is important in ensuring adequate pollination of tree fruit crops in the eastern United States. A field study was conducted to determine if nest modifications could reduce mite parasites and parasitoid natural enemies that attack managed O. cornifrons. Paraffin-coated paper liners (straws) were added to create modified nests, and were compared with the unmodified nests (i.e., nests without paper liners). In each nest, we recorded the number of nest cells with cleptoparasitic mites Chaetodactylus krombeini (Baker), and the presence of a parasitoid wasp Monodontomerus obscurus (Westwood). We also recorded the number of cocoons, male pupae, female pupae, and unconsumed pollen-nectar provision masses in these nests. Results showed that using paper liners in nest-tunnels greatly reduced the invasion of natural enemies of managed populations of O. cornifrons. Most notably, the addition of paper liners provided protection from invasion by C. krombeini mites, as the mean number of nest cells with mites were significantly lower in these lined nests compared to the nests without paper liners. A significantly higher number of male and female cocoons of O. cornifrons were recorded in the nests with paper liners. The population of M. obscurus was almost negligible in this field study. These results suggest that using nests with paper liners may accelerate the O. cornifrons population establishment and propagation in commercial orchards of rosaceous fruit crops, and possibly in other crops.

The Neurophysiological Bases of the Impact of Neonicotinoid Pesticides on the Behaviour of Honeybees.

Acetylcholine is the main excitatory neurotransmitter in the honeybee brain and controls a wide range of behaviours that ensure the survival of the individuals and of the entire colony. Neonicotinoid pesticides target this neurotransmission pathway and can thereby affect the behaviours under its control, even at doses far below the toxicity limit. These sublethal effects of neonicotinoids on honeybee behaviours were suggested to be partly responsible for the decline in honeybee populations. However, the neural mechanisms by which neonicotinoids influence single behaviours are still unclear. This is mainly due to the heterogeneity of the exposure pathways, doses and durations between studies. Here, we provide a review of the state of the science in this field and highlight knowledge gaps that need to be closed. We describe the agonistic effects of neonicotinoids on neurons expressing the different nicotinic acetylcholine receptors and the resulting brain structural and functional changes, which are likely responsible for the behavioural alterations reported in bees exposed to neonicotinoids.

Study Implies Active Ingredient In Roundup May Be Responsible For Decline Of Honeybee Populations

Study Implies Active Ingredient In Roundup May Be Responsible For Decline Of Honeybee Populations

Exposure of honey bees (Apis mellifera) to different classes of insecticides exhibit distinct molecular effect patterns at concentrations that mimic environmental contamination

Pesticides are implicated in the decline of honey bee populations. Many insecticides are neurotoxic and act by different modes of actions. Although a link between insecticide exposure and changed behaviour has been made, molecular effects underlying these effects are poorly understood. Here we elucidated molecular effects at environmental realistic concentrations of two organophosphates, chlorpyrifos and malathion, the pyrethroid cypermethrin, and the ryanodine receptor activator, chlorantraniliprole. We assessed transcriptional alterations of selected genes at three exposure times (24 h, 48 h, 72 h) in caged honey bees exposed to different concentrations of these compounds. Our targeted gene expression concept focused on several transcripts, including nicotinic acetylcholine receptor α 1 and α 2 (nAChRα1, nAChRα2) subunits, the multifunctional gene vitellogenin, immune system related genes of three immune system pathways, genes belonging to the detoxification system and ER stress genes. Our data indicate a dynamic pattern of expressional changes at different exposure times. All four insecticides induced strong alterations in the expression of immune system related genes suggesting negative implications for honey bee health, as well as cytochrome P450 enzyme transcripts suggesting an interference with metabolism. Exposure to neurotoxic chlorpyrifos, malathion and cypermethrin resulted in up-regulation of nAChRα1 and nAChRα2. Moreover, alterations in the expression of vitellogenin occurred, which suggests implications on foraging activity. Chlorantraniliprole induced ER stress which may be related to toxicity. The comparison of all transcriptional changes indicated that the expression pattern is rather compound-specific and related to its mode of action, but clusters of common transcriptional changes between different compounds occurred. As transcriptional alterations occurred at environmental concentrations our data provide a molecular basis for observed adverse effects of these insecticides to bees.

A pan-European epidemiological study reveals honey bee colony survival depends on beekeeper education and disease control.

Reports of honey bee population decline has spurred many national efforts to understand the extent of the problem and to identify causative or associated factors. However, our collective understanding of the factors has been hampered by a lack of joined up trans-national effort. Moreover, the impacts of beekeeper knowledge and beekeeping management practices have often been overlooked, despite honey bees being a managed pollinator. Here, we established a standardised active monitoring network for 5 798 apiaries over two consecutive years to quantify honey bee colony mortality across 17 European countries. Our data demonstrate that overwinter losses ranged between 2% and 32%, and that high summer losses were likely to follow high winter losses. Multivariate Poisson regression models revealed that hobbyist beekeepers with small apiaries and little experience in beekeeping had double the winter mortality rate when compared to professional beekeepers. Furthermore, honey bees kept by professional beekeepers never showed signs of disease, unlike apiaries from hobbyist beekeepers that had symptoms of bacterial infection and heavy Varroa infestation. Our data highlight beekeeper background and apicultural practices as major drivers of honey bee colony losses. The benefits of conducting trans-national monitoring schemes and improving beekeeper training are discussed.

Materially Engineered Artificial Pollinators

Summary Pollinating insects such as honeybees play a critical role in maintaining the natural environment. The decline in honeybee populations is a global issue with significant repercussions with respect to the pollination of plants. The simultaneous expression of multifunctionality from synthesized ionic liquid gels (ILGs) for biotechnology is presented in this study. We also demonstrate that, when mixed with photochromic organic compounds, ILGs display rapid color changes, similar to light-triggered camouflage, on living Musca domestica specimens. By further exploiting the physicochemical properties of ILGs, we were able to achieve effective pollen adsorption by ILG-functionalized Formica japonica specimens from Tulipa gesneriana flowers with high biocompatibility. In addition, a radiowave-controllable bio-inspired flying robot equipped with ILG-coated vertically aligned animal hairs could be used to successfully pollinate Lilium japonicum flowers. Such materially engineered artificial plant pollinators should lead to the development of high-performance robotics that can help counter the decline in honeybee populations.

Parasites, pathogens, and pests of honeybees in Asia

Asia is home to at least nine honeybee species, including the introduced Apis mellifera. In addition to A. mellifera and Apis cerana being widely employed for commercial beekeeping, the remaining nonmanaged species also have important ecological and economic roles on the continent. Species distributions of most honeybee species overlap in Southeast Asia. This promotes the potential for interspecific transmission of pests and parasites and their spread to other parts of the world by human translocation. The decline of honeybee populations is of great concern around the world, including in Asia. The global colony losses of A. mellifera are believed to be caused, in part, by parasites, pathogens, and pests originating from Asia, such as the mite Varroa destructor, the microsporidian Nosema ceranae, and some bee viruses. This review discusses important pests, pathogens, and parasites in both the introduced A. mellifera and native honeybees in Asia to provide an overall picture of honeybee health in the region and future threats to the apiculture industry.

Pesticides and reduced-risk insecticides, native bees and pantropical stingless bees: pitfalls and perspectives.

Although invertebrates generally have a low public profile, the honey bee, Apis mellifera L., is a flagship species whose popularity likely derives from the products it provides and its perceived ecological services. Therefore, the raging debate regarding honey bee decline has surpassed the realm of beekeepers, academia, industry and regulatory agencies and now also encompasses non-governmental agencies, media, fiction writers and the general public. The early interest and concern about honey bee colony collapse disorder (CCD) soon shifted to the bigger issue of pollinator decline, with a focus on the potential involvement of pesticides in such a phenomenon. Pesticides were previously recognised as the potential culprits of the reported declines, particularly the neonicotinoid insecticides owing to their widespread and peculiar use in agriculture. However, the evidence for the potential pivotal role of these neonicotinoids in honey bee decline remains a matter of debate, with an increased recognition of the multifactorial nature of the problem and the lack of a direct association between the noted decline and neonicotinoid use. The focus on the decline of honey bee populations subsequently spread to other species, and bumblebees became another matter of concern, particularly in Europe and the United States. Other bee species, ones that are particularly important in other regions of the world, remain the object of little concern (unjustifiably so). Furthermore, the continuous focus on neonicotinoids is also in need of revision, as the current evidence suggests that a broad spectrum of compounds deserve attention. Here we address both shortcomings.

An Inventory of Documented Diseases of African Honeybees

Current trends in global honeybee population changes have been linked to drastic declines in honeybee populations caused by complex interactions between pathogens, arthropod pests such as Varroa, pesticides, honeybee stress and habitat loss. Although substantial information exists for this sudden decline in honeybee populations in Europe and North America, in Africa the effect of this threat continues to draw debate. Despite recent reports showing the presence of V. destructor mites across the continent, knowledge on pathogens associated with bees and this mite in various parts of the continent is scanty. This review provides a comprehensive update on the documented diversity and geographic distribution of honeybee pathogens and points to the need of further information on these constraints of honeybee health.

EXAMINING THE ROLE OF foraging AND malvolio IN HOST‐FINDING BEHAVIOR IN THE HONEY BEE PARASITE, Varroa destructor (ANDERSON &amp; TRUEMAN)

When a female varroa mite, Varroa destructor (Anderson & Trueman), invades a honey bee brood cell, the physiology rapidly changes from feeding phoretic to reproductive. Changes in foraging and malvolio transcript levels in the brain have been associated with modulated intra-specific food searching behaviors in insects and other invertebrates. Transcription profiles for both genes were examined during and immediately following brood cell invasion to assess their role as potential control elements. Vdfor and Vdmvl transcripts were found in all organs of varroa mites with the highest Vdfor transcript levels in ovary-lyrate organs and the highest Vdmvl in Malpighian tubules. Changes in transcript levels of Vdfor and Vdmvl in synganglia were not associated with the cell invasion process, remaining comparable between early reproductive mites (collected from the pre-capping brood cells) and phoretic mites. However, Vdfor and Vdmvl transcript levels were lowered by 37 and 53%, respectively, in synganglia from reproductive mites compared to early reproductive mites, but not significantly different to levels in synganglia from phoretic mites. On the other hand, in whole body preparations the Vdfor and Vdmvl had significantly higher levels of transcript in reproductive mites compared to phoretic and early reproductive, mainly due to the presence of both transcripts accumulating in the eggs carried by the ovipositing mite. Varroa mites are a critical component for honey bee population decline and finding varroa mite genes associated with brood cell invasion, reproduction, ion balance and other physiological processes will facilitate development of novel control avenues for this honey bee parasite.

Factors influencing the foraging activity of the allodapine bee Braunsapis puangensis on creeping daisy (Sphagneticola trilobata) in Fiji

There is growing concern regarding the global decline of honey bee populations and the implications of this demise for the pollination of entomophilous crops (Potts et al. 2010, Groom and Schwarz 2011; Cornman et al. 2012). In the future we may rely on other insect species to perform crop pollination services, including naturally-occurring native or introduced species of bees (e.g. Rader et al. 2009). Pollination success of generalist plants tends to be positively related to pollinator diversity, so any habitat modifications that increase the number of pollinating species present at a site would JHR 35: 59–69 (2013) doi: 10.3897/JHR.35.6006 www.pensoft.net/journals/jhr

Conservation of Asian honey bees

East Asia is home to at least 9 indigenous species of honey bee. These bees are extremely valuable because they are key pollinators of about 1/3 of crop species, provide significant income to some of the world's poorest people, and are prey items for some endemic vertebrates. Furthermore, Southeast Asian Dipterocarp forests appear to be adapted to pollination by honey bees. Thus long-term decline in honey bee populations may lead to significant changes in the pollinator ecology of these forests, exacerbating the more direct effects of deforestation and wood harvesting on forest health. Although complete extinction of any honey bee species is seen as unlikely, local extinction is likely to occur across extensive areas. The most significant threats to local honey bee populations are deforestation and excessive hunting pressure. Conservation of East Asian honey bees requires immediate action to determine what rate of colony harvesting by honey hunters is sustainable. This requires information on the demography of hunted populations, particularly the intrinsic growth rates and the rates of harvest.

A Survey of Honey Bee Colony Losses in the U.S., Fall 2007 to Spring 2008

BackgroundHoney bees are an essential component of modern agriculture. A recently recognized ailment, Colony Collapse Disorder (CCD), devastates colonies, leaving hives with a complete lack of bees, dead or alive. Up to now, estimates of honey bee population decline have not included losses occurring during the wintering period, thus underestimating actual colony mortality. Our survey quantifies the extent of colony losses in the United States over the winter of 2007–2008.Methodology/Principal FindingsSurveys were conducted to quantify and identify management factors (e.g. operation size, hive migration) that contribute to high colony losses in general and CCD symptoms in particular. Over 19% of the country's estimated 2.44 million colonies were surveyed. A total loss of 35.8% of colonies was recorded; an increase of 11.4% compared to last year. Operations that pollinated almonds lost, on average, the same number of colonies as those that did not. The 37.9% of operations that reported having at least some of their colonies die with a complete lack of bees had a total loss of 40.8% of colonies compared to the 17.1% loss reported by beekeepers without this symptom. Large operations were more likely to have this symptom suggesting that a contagious condition may be a causal factor. Sixty percent of all colonies that were reported dead in this survey died without dead bees, and thus possibly suffered from CCD. In PA, losses varied with region, indicating that ambient temperature over winter may be an important factor.Conclusions/SignificanceOf utmost importance to understanding the recent losses and CCD is keeping track of losses over time and on a large geographic scale. Given that our surveys are representative of the losses across all beekeeping operations, between 0.75 and 1.00 million honey bee colonies are estimated to have died in the United States over the winter of 2007–2008. This article is an extensive survey of U.S. beekeepers across the continent, serving as a reference for comparison with future losses as well as providing guidance to future hypothesis-driven research on the causes of colony mortality.