Showing papers on "Varroa sensitive hygiene published in 2013"

Standard methods for varroa research

Abstract: SummaryVery rapidly after Varroa destructor invaded apiaries of Apis mellifera, the devastating effect of this mite prompted an active research effort to understand and control this parasite. Over a few decades, varroa has spread to most countries exploiting A. mellifera. As a consequence, a large number of teams have worked with this organism, developing a diversity of research methods. Often different approaches have been followed to achieve the same goal. The diversity of methods made the results difficult to compare, thus hindering our understanding of this parasite. In this paper, we provide easy to use protocols for the collection, identification, diagnosis, rearing, breeding, marking and measurement of infestation rates and fertility of V. destructor. We also describe experimental protocols to study orientation and feeding of the mite, to infest colonies or cells and measure the mite's susceptibility to acaricides. Where relevant, we describe which mite should be used for bioassays since their beha...

Crop Pollination Exposes Honey Bees to Pesticides Which Alters Their Susceptibility to the Gut Pathogen Nosema ceranae

Abstract: Recent declines in honey bee populations and increasing demand for insect-pollinated crops raise concerns about pollinator shortages. Pesticide exposure and pathogens may interact to have strong negative effects on managed honey bee colonies. Such findings are of great concern given the large numbers and high levels of pesticides found in honey bee colonies. Thus it is crucial to determine how field-relevant combinations and loads of pesticides affect bee health. We collected pollen from bee hives in seven major crops to determine 1) what types of pesticides bees are exposed to when rented for pollination of various crops and 2) how field-relevant pesticide blends affect bees’ susceptibility to the gut parasite Nosema ceranae. Our samples represent pollen collected by foragers for use by the colony, and do not necessarily indicate foragers’ roles as pollinators. In blueberry, cranberry, cucumber, pumpkin and watermelon bees collected pollen almost exclusively from weeds and wildflowers during our sampling. Thus more attention must be paid to how honey bees are exposed to pesticides outside of the field in which they are placed. We detected 35 different pesticides in the sampled pollen, and found high fungicide loads. The insecticides esfenvalerate and phosmet were at a concentration higher than their median lethal dose in at least one pollen sample. While fungicides are typically seen as fairly safe for honey bees, we found an increased probability of Nosema infection in bees that consumed pollen with a higher fungicide load. Our results highlight a need for research on sub-lethal effects of fungicides and other chemicals that bees placed in an agricultural setting are exposed to.

Acaricide, fungicide and drug interactions in honey bees (Apis mellifera).

Abstract: Background Chemical analysis shows that honey bees (Apis mellifera) and hive products contain many pesticides derived from various sources. The most abundant pesticides are acaricides applied by beekeepers to control Varroa destructor. Beekeepers also apply antimicrobial drugs to control bacterial and microsporidial diseases. Fungicides may enter the hive when applied to nearby flowering crops. Acaricides, antimicrobial drugs and fungicides are not highly toxic to bees alone, but in combination there is potential for heightened toxicity due to interactive effects.

Field-Level Sublethal Effects of Approved Bee Hive Chemicals on Honey Bees (Apis mellifera L)

Abstract: In a study replicated across two states and two years, we tested the sublethal effects on honey bees of the miticides Apistan (tau fluvalinate) and Check Mite+ (coumaphos) and the wood preservative copper naphthenate applied at label rates in field conditions. A continuous covariate, a colony Varroa mite index, helped us disambiguate the effects of the chemicals on bees while adjusting for a presumed benefit of controlling mites. Mite levels in colonies treated with Apistan or Check Mite+ were not different from levels in non-treated controls. Experimental chemicals significantly decreased 3-day brood survivorship and increased construction of queen supercedure cells compared to non-treated controls. Bees exposed to Check Mite+ as immatures had higher legacy mortality as adults relative to non-treated controls, whereas bees exposed to Apistan had improved legacy mortality relative to non-treated controls. Relative to non-treated controls, Check Mite+ increased adult emergence weight. Although there was a treatment effect on a test of associative learning, it was not possible to statistically separate the treatment means, but bees treated with Apistan performed comparatively well. And finally, there were no detected effects of bee hive chemical on colony bee population, amount of brood, amount of honey, foraging rate, time required for marked released bees to return to their nest, percentage of released bees that return to the nest, and colony Nosema spore loads. To our knowledge, this is the first study to examine sublethal effects of bee hive chemicals applied at label rates under field conditions while disambiguating the results from mite control benefits realized from the chemicals. Given the poor performance of the miticides at reducing mites and their inconsistent effects on the host, these results defend the use of bee health management practices that minimize use of exotic hive chemicals.

Varying congruence of hygienic responses to Varroa destructor and freeze-killed brood among different types of honeybees

Abstract: Honeybees, Apis mellifera, selected for the hygienic removal of freeze-killed brood (FKB), resist several microbial diseases and have some resistance to Varroa destructor. Bees with Varroa-sensitive hygiene (VSH) have good resistance to V. destructor. We determined whether the response to FKB could be used to select for VSH by measuring the responses of different bees (VSH, FKB-selected, F1 VSH, and unselected control) to combs with FKB and combs with mite-infested brood. All bee types completely removed much FKB (77–88 %) within 24 h. The removal of mite-infested brood after 1 week was much more variable among bee types (VSH, 66 %; F1 VSH, 51 %; FKB hygienic, 14 %; control, 3 %). There was some relationship between 24-h manipulation of FKB cells (i.e., cell contents at least partially removed) and the removal of mite-infested brood, but this appears to have little practical relevance because of a large inherent variation.

Honey bee lines selected for high propolis production also have superior hygienic behavior and increased honey and pollen stores.

Abstract: Honey bees use propolis to defend against invaders and disease organisms. As some colonies produce much more propolis than others, we investigated whether propolis collecting is associated with disease resistance traits, including hygienic behavior and resistance to the parasitic bee mite, Varroa destructor. The three highest (HP) and three lowest propolis-producing (LP) colonies among 36 Africanized honey bee colonies were initially selected. Queens and drones from these colonies were crossed through artificial insemination to produce five colonies of each of the following crosses: HP♀ X HP♂, LP♀ X HP♂, HP♀ X LP♂, and LP♀ X LP♂. Colonies headed by HP♀ X HP♂ queens produced significantly more propolis than those with HP♀ X LP♂ and LP♀ X HP♂ queens and these in turn produced significantly more propolis than those headed by LP♀ X LP♂ queens. The brood cell

Hygienic Behavior in Honey Bees (Hymenoptera: Apidae): Effects of Brood, Food, and Time of the Year

Abstract: Hygienic behavior in honey bees is a heritable trait of individual workers that confers colony-level resistance against various brood diseases. Hygienic workers detect and remove dead or diseased brood from sealed cells. However, this behavior is quite rare, with only c.10% of unselected colonies showing high levels of hygiene. Beekeepers can potentially increase this by screening colonies for hygiene and breeding from the best. However, the level of hygiene expressed by a colony is variable, which poses a challenge to colony selection. In this study, we systematically varied two factors thought to be of importance in influencing hygiene levels, "nectar" availability, by feeding or not feeding sucrose syrup, and brood amount, by adding or removing brood, to determine what effect they had on hygienic behavior. We tested 19 colonies repeatedly over a 4-mo period using the freeze-killed brood assay, a standard technique to quantify hygienic behavior. Two days after freeze-killed brood treatment, our colonies showed a wide range of brood removal levels, with colony means ranging from 31.7 +/- 22.5 to 93 +/- 6.9 (mean % +/- SD). Neither the food nor the brood manipulation had an effect on hygiene levels. Colony size and time of year were also nonsignificant. The only significant effect was a three-way interaction between syrup availability, amount of brood, and time of the year, resulting in reduced hygienic behavior early in the season (spring), in colonies with added brood that were not fed sucrose syrup. Overall, these results suggest that hygienic behavior is not greatly affected by environmental conditions typical of a real-life beekeeping, and that screening of colonies can be done anytime without special regard to nectar conditions or brood levels.

Fate of dermally applied miticides fluvalinate and amitraz within honey bee (Hymenoptera: Apidae) bodies.

Abstract: Varroa mites, Varroa destructor Anderson & Trueman, are economically important pests of honey bees. Varroa mites are principally controlled within honey bee colonies using miticides. However, despite their importance in managing mite populations for apiculture, potential effects of miticides on honey bees are poorly understood. Using gas chromatography-same ionization detection, we investigated concentrations, over variable time frames and within different body regions, of two commonly used miticides, tau-suvalinate and amitraz, after dermal exposure to honey bees. We also quantiÞed mortality of honey bees exposed to each miticide at both a low and high dose. SigniÞcant differences were observed in distributions of miticides among body regions. Within honey bee body parts, tau-suvalinate was more readily absorbed and decreased in concentration more rapidly than amitraz. Mortality increased with higher dosages of miticides, and at higher dosages mortality was greater from suvalinate than from amitraz. For individual honey bees, our results for rate of breakdown suggest that suvalinate may be the preferred miticide for apiculturists, whereas our mortality results suggest that amitraz may be preferable. Either choice must be weighed against geographic variation in varroa resistance to each pesticide and attendant costs of parasitism.

Comments on: "Varroa destructor: Research avenues towards sustainable control"

Abstract: (2013). Comments on: “Varroa destructor, research avenues towards sustainable control”. Journal of Apicultural Research: Vol. 52, No. 2, pp. 69-71.

Efficacy of Apilife Var® and Thymovar® against Varroa destructor as an autumn treatment in a cool climate

Abstract: SummaryThe relationship between Varroa destructor and its European honey bee host, Apis mellifera is such that colony mortality is inevitable if mite populations are not controlled Although in the past, synthetic pyrethroids and organophosphates were used effectively, mite resistance has developed, and today beekeepers are relying more on thymol-based products such as Apilife Var® and Thymovar® These products, although toxic to the mite are known to show high variability in efficacy under field conditions, as ambient temperatures > 15°C are essential for the evaporation of the active ingredient thymol To assess their efficacy as an autumn treatment, in cool temperate climates such as Ireland, a field trial was carried out in 2009 A total of 26 colonies were standardised for brood area, and treatments were administered on 21 August following the manufacturers' instructions To estimate the percentage efficacy of the test treatments, oxalic acid was administered as a winter treatment on 11 December Thy

Exploring a treatment strategy for long-term increase of varroa tolerance on Marmara Island, Turkey

Abstract: Summary We explored practical steps to implement a sustainable treatment against Varroa destructor which is adapted to common beekeeping situations, and applies conventional control but nevertheless exerts selection pressure towards increased mite tolerance in honey bees. This approach approximates conditions of natural selection in host-parasite systems, and is supported by evidence that the impact of V. destructor decreases when bee populations are overexploited by the parasites. However, instead of a “live or let die” approach to selection, which is not feasible for commercial beekeeping, death of highly infested colonies was mimicked by treatment and requeening. We established a feasible treatment threshold based on powder sugar shaking of worker bee samples in 250 colonies kept by four beekeepers on the island of Marmara, Turkey. We subsequently requeened heavily infested colonies with queens from lightly infested colonies using simple methods. We found that although one third of the colonies were routinely left untreated, it was possible to decrease mean mite infestation levels and maintain a stable bee population in our apiaries.

Thymol as control agent of mites (Varroa destructor) on honeybees (Apis mellifera).

Abstract: Studies were carried out on thymol as a controlling agent -1 for bee mites. In this study thymol powder (5mg hive ) was compared with formic acid 65 % and fluvalinate (strip) as standard control measure against Varroa mite. The mite mortality rate was recorded in honeybee colonies of Apis mellifera during 2011-12 at research farm of Beekeeping and Hill Fruit Pests Research Station, Rawalpindi. Analysis of variance for different treatments indicated (F=3.64, F>P=0.15) significantly different effect among treatments as well as for the control of mite. The average efficacy of thymol was 73.72% as compared to 69.21% by fluvalinate, 72.23% by formic acid and 13.1% in control. The reduction in the effectiveness of fluvalinate may be attributed to the development of resistance against fluvalinate strip.

Honey bee colonies from different races show variation in defenses against the varroa mite in a ‘common garden’

Abstract: Honeybee[ApismelliferaL.(Hymenoptera:Apidae)]geneticdiversitymaybethekeytorespondingto novel health challenges faced by this important pollinator. In this study, we first compared colo-nies of four honey bee races, A. m. anatoliaca, A. m. carnica, A. m. caucasica,andA. m. syriacafrom Turkey, with respect to honey storage, bee population size, and defenses against varroa. Themite Varroa destructor Anderson & Trueman (Acari: Varroidae) is an important pest of honey beecolonies. There are genetic correlates with two main defenses of bees against this parasite: hygienicbehavior, or removing infested brood, and grooming, which involves shaking and swiping off mitesandbitingthem. In thesecondpartofthis study,weexaminedtherelationshipofthesetwo types ofdefenses, hygiene andgrooming,and their correlationwith infestation ratesin 32genetically diversecolonies in a ‘common garden’ apiary. Mite biting was found to be negatively correlated with miteinfestationlevels. Introduction Honey bees, Apis mellifera L. (Hymenoptera: Apidae), areimportant as generalist pollinators both for conservingwild flora and for increasing agricultural crop yields(Morse & Calderone, 2000). Recent losses of honey beecolonies across the world (Oldroyd, 2007; vanEngelsdorpet al., 2008, 2011; Giray et al., 2010; Neumann & Carreck,2010)hasraisedthequestionofsynergisticeffectsofmulti-ple factors beingresponsiblefor these losses (seeHuang G Harbo & Harris, 2005; Ibrahim S Arechavaleta-Velasco GRivera-Marchand et al., 2012). Removal and biting couldbedistinctcomponents ofgrooming,becauseshakingand

Responses to Varroa destructor and Nosema ceranae by several commercial strains of Australian and North American honeybees (Hymenoptera: Apidae)

Abstract: The potential impact of varroa (Varroa destructor, Anderson & Trueman) on Australian beekeeping and agriculture depends in part on the levels of resistance to this parasite expressed by Australian commercial honeybees (Apis mellifera). The responses of seven lines of Australian honeybees to V. destructor were compared with the responses of a stock of Italian honeybees from the United States known for its susceptibility to V. destructor and two stocks known for their resistance to V. destructor, Russian honeybees (RHB) and a stock expressing the varroa sensitive hygiene trait (VSH). The experiment began in May with uniform colonies having uniform infestation of V. destructor. V. destructor infestations measured as the percentage of adult bees infested in the Australian lines and the Italian stock rose from less than 10% in August to over 25% in October. From August to November, 44% of both the Australian and Italian colonies died while strongly exhibiting symptoms of parasitic mite syndrome. In contrast, RHB and VSH colonies displayed comparative resistance to V. destructor. Their infestation rates rose from about 5% in August to 10% (RHB) and 14% (VSH) in October. Likely, some of this increase resulted from invasion pressure by mites from the dying Australian and Italian colonies. During the August to November period, 4.4% of the RHB and 14.3% of the VSH colonies died. In comparisons of the seven Australian lines, only nonsignificant and trivial differences were found for infestation and mortality rates. All Australian lines were highly susceptible to V. destructor. Additionally, evaluations of rates of Nosema ceranae infections were made throughout the course of the experiment. Although high levels of infection were found across all stocks and lines, no stock or line exhibited an adverse effect from N. ceranae infection.

Variation of hygienic behaviour (nest cleaning behaviour) in honey bee, Apis cerana indica F. in different eco habitats of South India

Abstract: Honey bees play a significant role in agriculture as they are important pollinators The bees produce propolies, royal jelly and bee venom that are playing increasing roles in health, food and alternative medicine Hygienic behaviour is a complex trait that has a strong environmental as well as genetic component where the latter depends upon the age and size of worker bee Genes are known to control hygienic behaviour in honeybees, similar to other characters in living organism This behaviour is very important to the health and survival of the colony and individual bee According to Bailey & Ball (1991) bees are known for the very good hygienic behaviour compared to other animal models

Mite infestation of honeybee (Apis mellifera) in apiaries of North East of Iran

Abstract: Varroa destructor, Acarapis woodi and Tropilaelaps spp. are the main parasitic honeybee mites. The present study was carried out to determine the situation of parasitic honeybee mite infestation in the apiaries of North East of Iran. A total of 54 apiaries were sampled from April to July 2011 and April to July 2012. Five colonies were randomly selected in each apiary (overall 270 colonies) and 50 adult honeybees and a piece of sealed brood cells were taken from each colony. Parasitological examinations showed that prevalence of Varroa infestation in apiaries of this region was 31.5%. Likewise, the Varroa infestation rate of honeybee colonies was 7.40% in the spring. The measured morphometrical characteristics showed that Varroa infestative species in this region was V. destructor. In this study, infestation with A. woodi and Tropilaelaps spp. were not observed. In conclusion, Varroa is the main parasitic mite of honey bees in the study area. It is recommended that infested colonies be monitored and mite population level in the hives be determined and based on economic threshold treatment started.

The effect of pathogens on honeybee learning and foraging behaviour

Abstract: The European honeybee, Apis mellifera, is important economically not just for honey production but also as a pollinator. Bee pollinated plants contribute towards one third of the food eaten worldwide. However, honeybee numbers in some areas are declining. A range of interacting factors are thought to be involved, including pathogens and parasites, loss of forage, pesticide use, bad weather, and limited genetic variability. Pathogens are also known to cause changes in the behaviour of their hosts and these premortality and sublethal effects of disease may well play a role in colony declines and are the focus of this thesis. For individual bees the fungus Metarhizium anisopliae was used as a model pathogen and RT-Q-PCR was used to detect and quantify naturally occurring pathogens. In field colonies the level of infestation of the parasitic mite Varroa destructor was modified as a surrogate for disease load as the amounts of many viruses correlate with mite levels. Survival experiments showed that both disease load and forage availability had an effect on honeybee longevity and feeding the bees pollen increased their survival. Learning experiments showed that both the fungus and some of the bees’ naturally occurring pathogens caused changes in the learning ability of young adult and older forager bees. Young adult bees were better able to learn when infected with the fungus, possibly because it made them more responsive to the sucrose stimulus, whilst older forager bees where less able to learn when infected with the fungus. Harmonic radar was used to show that honeybee flight ability was affected by naturally occurring pathogens, especially deformed wing virus which caused bees to fly shorter distances and for shorter amounts of time than uninfected bees. Observation hives were used to study in-hive behaviour showing that bees with more pathogens were likely to start foraging earlier than healthier bees.

Effect of the honey bee subspecies on Varroa destructor population growth and brood infestation.

Abstract: Summary The aim of the study was to check the effect of the honey bee subspecies on Varroa destructor population growth and on brood infestation by the parasite. The studies were carried out in 2009-2010. The following five subspecies of bees were tested: Carniolan bees represented by two lines, Kortowka and Dobra; Caucasian bees of the Woźnica line; Central European bees of the Augustowska line; crossbreeds achieved by the absorptive crossing of A. m. capensis with A. m. carnica drones selected for a short post capping period (PCP), bred at the Apiculture Division in Olsztyn. The coefficient of V. destructor population growth was similar in all groups, ranging from 1.3 to 1.5. The level of infestation of broods by Varroa destructor in all groups was also similar (17.2 to 19.6%) and no statistically significant differences were noted. We conclude that the honey bee subspecies has no effect on parasite population growth.

Effect of synthetic queen mandibular pheromone on pollination of cotton by honey bees, Apis mellifera (Hymenoptera: Apidae)

Abstract: The effectiveness of a commercial bee attractant, synthetic honey bee queen mandibular pheromone (Fruit Boost) for enhancing pollination of Gossypium hirsutum was evaluated in a transgenic (Bt) cotton crop. The study assessed the number of bee visitations to blossoms of plants treated with Fruit Boost as well, as effects on fruit set, yield, and lint quality. Bee activity on plots sprayed with pheromone concentrations of 50 and 500 queen equivalents (QEQ) /ha did not differ significantly from water-only control, on the day of application or the subsequent day. Application of the pheromone did not increase fruit set, yield, or lint quality. Two consecutive pheromone applications, applied two days apart, were not significantly different from a single application for any parameter. Keywords—Apis mellifera, cotton, pollination, QMP pheromone.

Oral Vaccination of Honeybees Against Varroa Destructor

Abstract: First reported in the USA, a mysterious so-called colony collapse disorder (CCD) decimated the bee colonies there between 50 and 90%. The huge global loss of honey bees as pollinators has a dramatic impact of agricultural pollination. About 130 crops, nuts, fruits, vegetables are pollinated by A.mellifera, with an overall value of more than $ 15 billion in the USA, and more than € 14 billion for the EU in 2005. In all CCD cases an overload of bloodsucking Varroa mites is detectable and Varroa is currently considered the major threat for apiculture. Honeybees possess a humoral and cellular immune system, e.g., multiple antimicrobial peptides and immune reactive enzymes. Varroa mites overcome the bee’s immune response by massive suppressing some of these immune genes. We developed a DNA vaccine for oral application which is able to reconstitute the full function of the bee’s immune system. This vaccine is absolutely biological safe, well-tolerated, show no side effects, and does not form any burden for the environment.

The Control of Varroa Destructor in Apis Mellifera by the Isolation of the Brood Area

Abstract: Varroa destructor is a parasitic of honeybees that, beginning in the 1960´s, has become a worldwide serious economic problem. Although there are miticides capable of controlling the infestation they contaminate the honey. In this paper I question if it is possible to implement a perfectly different strategy that is to isolate the brood area from the exterior where the forager-bees stay in just in the honey area. To decrease management costs, I also question if it is possible to have a super-colony with up to 30 queen-bees isolated brood areas that share the same honey area.

Defence strategies and self medication in honey bee (Apis mellifera).

Abstract: The defence strategies of the honey bee is strongly related to their behaviour. As a social insect, the risk of infection is very high, therefore, unless humans interfere, they have to deal themselves with the parasites, which sometimes could be very successful. A huge advantage is on the honey bee side, because there are thousands of individuals inside a colony, so they can unify their effort to eliminate the intruders on one hand. On the other hand, based on the honey bee – human relationship too, the honey bees have developed an evolutionary capacity of diagnose the disease and take some action. We here show that despite the virulence of some pathogens, the honey bees are capable of defend themselves and, sometimes, they can even resort to self medication.

Variability of the production characteristics of the isolated traits of the honey bee in the area of trebinje

Abstract: To obtain high yield in beekeeping and to exploit potential of the honeybee pasture in the region of the Republic of Srpska it is necessary to use carefully chosen honeybee queens with a good biological potential. Protection of the local subpopulations of the honeybees in order to preserve biodiversity of this kind in the Republic of Srpska is the second important factor for the choice of the honeybees mother queens and their further selection. In the paper we have examined 4 bee traits situated in the selection centre nearby Trebinje. This area is on the border of BH, Montenegro and Croatia in the zone of Mediterranean climate and it is additionally interesting for the isolation of the honeybee traits in order to have new honeybee queens in the earlier phases of beekeeping seasons than in other areas of the RS. The amount of bees, brood, honey, pollen, brood quality and behaviour was investigated in two spring and one autumn survey. All data have been carefully collected, statistically processed and analysed. Trait V2 had the biggest amount of bees in the first and second spring examination (2.26 and 4.84 frames) and statistically it is importantly different from other traits by this characteristic (P< 0.01). The same trait had the biggest amount of brood in spring examinations and it was importantly different from the other traits (P< 0.01). The best brood quality (mark 3) in all 3 examinations during the year had traits V2 and G2. All examined traits showed variability that provides successful improvement of wanted characteristics and selection of suitable mother queens in order to get high productivity in beekeeping.