Showing papers on "Varroa sensitive hygiene published in 2011"

Characteristics of honey bee colonies (Apis mellifera) in Sweden surviving Varroa destructor infestation

Abstract: A population of European honey bees (Apis mellifera) surviving Varroa destructor mite infestation in Sweden for over 10 years without treatment, demonstrate that a balanced host–parasite relationship may evolve over time. Colony-level adaptive traits linked to Varroa tolerance were investigated in this population to identify possible characteristics that may be responsible for colony survival in spite of mite infestations. Brood removal rate, adult grooming rate, and the mite distribution between brood and adults were not significantly different in the untreated population compared with treated control colonies. However, colony size and the reproductive success of the mite were significantly reduced in surviving colonies compared with control colonies. Our data suggest that colony-level adaptive traits may limit mite population growth by reducing mite reproduction opportunities and also by suppressing the mite reproductive success.

Infestation of Japanese native honey bees by tracheal mite and virus from non-native European honey bees in Japan.

Abstract: Invasion of alien species has been shown to cause detrimental effects on habitats of native species. Insect pollinators represent such examples; the introduction of commercial bumble bee species for crop pollination has resulted in competition for an ecological niche with native species, genetic disturbance caused by mating with native species, and pathogen spillover to native species. The European honey bee, Apis mellifera, was first introduced into Japan for apiculture in 1877, and queen bees have been imported from several countries for many years. However, its effects on Japanese native honey bee, Apis cerana japonica, have never been addressed. We thus conducted the survey of honey bee viruses and Acarapis mites using both A. mellifera and A. c. japonica colonies to examine their infestation in native and non-native honey bee species in Japan. Honey bee viruses, Deformed wing virus (DWV), Black queen cell virus (BQCV), Israeli acute paralysis virus (IAPV), and Sacbrood virus (SBV), were found in both A. mellifera and A. c. japonica colonies; however, the infection frequency of viruses in A. c. japonica was lower than that in A. mellifera colonies. Based on the phylogenies of DWV, BQCV, and SBV isolates from A. mellifera and A. c. japonica, DWV and BQCV may infect both honey bee species; meanwhile, SBV has a clear species barrier. For the first time in Japan, tracheal mite (Acarapis woodi) was specifically found in the dead honey bees from collapsing A. c. japonica colonies. This paper thus provides further evidence that tracheal-mite-infested honey bee colonies can die during cool winters with no other disease present. These results demonstrate the infestation of native honey bees by parasite and pathogens of non-native honey bees that are traded globally.

Dynamics of Persistent and Acute Deformed Wing Virus Infections in Honey Bees, Apis mellifera

Abstract: The dynamics of viruses are critical to our understanding of disease pathogenesis Using honey bee Deformed wing virus (DWV) as a model, we conducted field and laboratory studies to investigate the roles of abiotic and biotic stress factors as well as host health conditions in dynamics of virus replication in honey bees The results showed that temperature decline could lead to not only significant decrease in the rate for pupae to emerge as adult bees, but also an increased severity of the virus infection in emerged bees, partly explaining the high levels of winter losses of managed honey bees, Apis mellifera, around the world By experimentally exposing adult bees with variable levels of parasitic mite Varroa destructor, we showed that the severity of DWV infection was positively correlated with the density and time period of Varroa mite infestation, confirming the role of Varroa mites in virus transmission and activation in honey bees Further, we showed that host conditions have a significant impact on the outcome of DWV infection as bees that originate from strong colonies resist DWV infection and replication significantly better than bee originating from weak colonies The information obtained from this study has important implications for enhancing our understanding of host‑pathogen interactions and can be used to develop effective disease control strategies for honey bees

Three QTL in the honey bee Apis mellifera L. suppress reproduction of the parasitic mite Varroa destructor

Abstract: Varroa destructor is a highly virulent ectoparasitic mite of the honey bee Apis mellifera and a major cause of colony losses for global apiculture. Typically, chemical treatment is essential to control the parasite population in the honey bee colony. Nevertheless a few honey bee populations survive mite infestation without any treatment. We used one such Varroa mite tolerant honey bee lineage from the island of Gotland, Sweden, to identify quantitative trait loci (QTL) controlling reduced mite reproduction. We crossed a queen from this tolerant population with drones from susceptible colonies to rear hybrid queens. Two hybrid queens were used to produce a mapping population of haploid drones. We discriminated drone pupae with and without mite reproduction, and screened the genome for potential QTL using a total of 216 heterozygous microsatellite markers in a bulk segregant analysis. Subsequently, we fine mapped three candidate target regions on chromosomes 4, 7, and 9. Although the individual effect of these three QTL was found to be relatively small, the set of all three had significant impact on suppression of V. destructor reproduction by epistasis. Although it is in principle possible to use these loci for marker-assisted selection, the strong epistatic effects between the three loci complicate selective breeding programs with the Gotland Varroa tolerant honey bee stock.

The habitat disruption induces immune‐suppression and oxidative stress in honey bees

Abstract: The honey bee is a major insect used for pollination of many commercial crops worldwide. Although the use of honey bees for pollination can disrupt the habitat, the effects on their physiology have never been determined. Recently, honey bee colonies have often collapsed when introduced in greenhouses for pollination in Japan. Thus, suppressing colony collapses and maintaining the number of worker bees in the colonies is essential for successful long-term pollination in greenhouses and recycling of honey bee colonies. To understand the physiological states of honey bees used for long-term pollination in greenhouses, we characterized their gene expression profiles by microarray. We found that the greenhouse environment changes the gene expression profiles and induces immune-suppression and oxidative stress in honey bees. In fact, the increase of the number of Nosema microsporidia and protein carbonyl content was observed in honey bees during pollination in greenhouses. Thus, honey bee colonies are likely to collapse during pollination in greenhouses when heavily infested with pathogens. Degradation of honey bee habitat by changing the outside environment of the colony, during pollination services for example, imposes negative impacts on honey bees. Thus, worldwide use of honey bees for crop pollination in general could be one of reasons for the decline of managed honey bee colonies.

Invasion of Varroa destructor mites into mite-free honey bee colonies under the controlled conditions of a military training area

Abstract: SummaryThe honey bee mite Varroa destructor can be spread between colonies by vertical transmission, particularly when heavily infested colonies are robbed by foraging bees from neighbouring hives. We quantified the invasion of V. destructor into mite free colonies on a military training area not accessible to other beekeepers. Ten “mite receiver colonies” continuously treated against V. destructor were placed at distances of one to 1.5 km from four heavily infested “mite donor colonies”. Over a two month period from August to October, the population of bees, brood, and V. destructor in the donor colonies were estimated at three week intervals and the invasion of V. destructor into the receiver colonies was recorded every 7–12 days. During the experimental period, between 85 and 444 mites per colony were introduced into the receiver colonies. There were no significant differences in the invasion rates in relation to the distance between donor and receiver colonies. In total, 2,029 mites were found in the ...

Asynchronous Development of Honey Bee Host and Varroa destructor (Mesostigmata: Varroidae) Influences Reproductive Potential of Mites

Abstract: A high proportion of nonreproductive (NR) Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae), is commonly observed in honey bee colonies displaying the varroa sensitive hygienic trait (VSH). This study was conducted to determine the influence of brood removal and subsequent host reinvasion of varroa mites on mite reproduction. We collected foundress mites from stages of brood (newly sealed larvae, prepupae, white-eyed pupae, and pink-eyed pupae) and phoretic mites from adult bees. We then inoculated these mites into cells containing newly sealed larvae. Successful reproduction (foundress laid both a mature male and female) was low (13%) but most common in mites coming from sealed larvae. Unsuccessful reproductive attempts (foundress failed to produce both a mature male and female) were most common in mites from sealed larvae (22%) and prepupae (61%). Lack of any progeny was most common for mites from white-eyed (83%) and pink-eyed pupae (92%). We also collected foundress mites from sealed larvae and transferred them to cells containing newly sealed larvae, prepupae, white-eyed pupae, or pink-eyed pupae. Successful reproduction only occurred in the transfers to sealed larvae (26%). Unsuccessful reproductive attempts were most common in transfers to newly sealed larvae (40%) and to prepupae (25%). Unsuccessful attempts involved the production of immature progeny (60%), the production of only mature daughters (26%) or the production of only a mature male (14%). Generally, lack of progeny was not associated with mites having a lack of stored sperm. Our results suggest that mites exposed to the removal of prepupae or older brood due to hygiene are unlikely to produce viable mites if they invade new hosts soon after brood removal. Asynchrony between the reproductive status of reinvading mites and the developmental stage of their reinvasion hosts may be a primary cause of NR mites in hygienic colonies. Even if reinvading mites use hosts having the proper age for infestation, only a minority of them will reproduce.

Effects of honey bee virus prevalence, Varroa destructor load and queen condition on honey bee colony survival over the winter in Belgium

Abstract: SummarySince 1999, European beekeepers have reported increased mortality in overwintering honey bee, Apis mellifera L. colonies. Viral infections are often cited as the potential cause for increased mortality. Many honey bee viruses commonly occur within bee populations and in many cases infected colonies appear asymptomatic. There is increasing evidence that the global spread of Varroa destructor has resulted in a significant change in the prevalence, distribution and/or virulence of viruses causing mortality in honey bee colonies. We report here the first survey of the prevalence of five RNA bee viruses and their effect on overwintering survival of Belgian honey bee colonies. In the autumn of 2006, samples of adult bees were removed from 36 apiaries. Adult bee samples were analyzed by using RT-PCR for virus identification. Varroa mite prevalence in these samples was also quantified. A follow up visit of colonies in the spring permitted us to assess colony survivorship which permitted the effect, if any,...

Age-related changes in the behavioural response of honeybees to Apiguard®, a thymol-based treatment used to control the mite Varroa destructor.

Abstract: The parasitic mite Varroa destructor is responsible for heavy losses in honey bee colonies and represents a major threat to the beekeeping industry. Essential oils offer an attractive alternative to the use of synthetic chemicals for the control of varroa. Amongst them, thymol appears to be particularly promising. However, treatments using thymol as their active substance, such as the gel formulation Apiguard(®), are suspected to have adverse effects on honey bee colonies. In this study, laboratory assays are used to investigate the effects of Apiguard(®) exposure on honey bee behaviour. Our results reveal that honey bee responses to this anti-varroa treatment change with honey bee age. While 2-day-old bees respond neutrally to Apiguard(®), older bees generally avoid the Apiguard(®) gel. Responses of forager bees were particularly striking. Foragers appear to be repelled by Apiguard(®). Touching their antennae with Apiguard(®) induces robust fanning behaviour. Our data suggest, however, that forager bees exposed to Apiguard(®) in the hive can become habituated to this treatment. These results offer interesting new perspectives on the effects of Apiguard(®) on honey bee behaviour and serve to highlight age-related changes in honey bee responses to gustatory, as well as olfactory cues.

Expression of Varroa Sensitive Hygiene (VSH) in Commercial VSH Honey Bees (Hymenoptera: Apidae)

Abstract: We tested six commercial sources of honey bees, Apis mellifera L. (Hymenoptera: Apidae), whose breeding incorporated the trait of Varroa sensitive hygiene (VSH). VSH confers resistance to the parasitic mite Varroa destructor Anderson & Trueman by enhancing the ability of the bees to hygienically remove mite-infested brood. VSH production queens (i.e., queens commercially available for use in beekeepers' production colonies) from the six sources were established in colonies which later were measured for VSH. Their responses were compared with those of colonies with three other types of queens, as follows: VSH queens from the selected closed population maintained by USDA-ARS for research and as a source of breeding germplasm, queens from the cooperating commercial distributor of this germplasm, and queens of a commercial, mite-susceptible source. The reduction of mite infestation in brood combs exposed to test colonies for 1 wk differed significantly between groups. On average, colonies with VSH production queens reduced infestation by 44%. This group average was intermediate between the greater removal by pure ARS VSH (76%) and the cooperators' breeding colonies (64%), and the lesser removal by susceptible colonies (7%). VSH production colonies from the different sources had variable expression of hygiene against mites, with average reduced infestations ranging from 22 to 74%. In addition, infertility was high among mites that remained in infested cells in VSH breeder colonies from ARS and the commercial distributor but was lower and more variable in VSH production colonies and susceptible colonies. Commercial VSH production colonies supply mite resistance that generally seems to be useful for beekeeping. Resistance probably could be improved if more VSH drones sources were supplied when VSH production queens are being mated.

Varroa destructor infestation of honey bee (Apis mellifera adansonii) colonies in Benin

Abstract: (2011). Varroa destructor infestation of honey bee (Apis mellifera adansonii) colonies in Benin. Journal of Apicultural Research: Vol. 50, No. 4, pp. 321-322.

The Effects of Varroa (Varroa destructor) Infestation Level on Wintering Ability and Survival Rates of Honeybee (Apis mellifera L.) Colonies

Abstract: Summary This study was carried out to determine the eff ects of the Varroa (Varroa destructor) infestation level (in fall) on the wintering ability and survival rates of honeybee (A. mellifera) colonies. Four diff erent infestation levels of Varroa in honeybee colonies were tested in this study. Ten honeybee colonies, in which infestation levels were similar, were used for each group. The average wintering abilities in low, medium, high and extreme groups were found to be 94.28%, 91.42%, 63.92% and 23.28% respectively. An average survival rate for the low, medium, high and extreme groups were found to be 100%, 100%, 80% and 40% respectively. Diff erences among the groups for wintering ability (P<0.01) were significant.

Regular dorsal dimples and damaged mites of Varroa destructor in some Iranian honey bees (Apis mellifera).

Abstract: The frequency of damaged Varroadestructor Anderson and Trueman (Mesostigmata: Varroidae) found on the bottom board of hives of the honey bee, Apis mellifera L. (Hymenoptera: Apidae) has been used as an indicator of the degree of tolerance or resistance of honey bee colonies against mites. However, it is not clear that this measure is adequate. These injuries should be separated from regular dorsal dimples that have a developmental origin. To investigate damage to Varroa mites and regular dorsal dimples, 32 honey bee (A. mellifera) colonies were selected from four Iranian provinces: Isfahan, Markazi, Qazvin, and Tehran. These colonies were part of the National Honey bee Breeding Program that resulted in province-specific races. In April, Varroa mites were collected from heavily infested colonies and used to infest the 32 experimental colonies. In August, 20 of these colonies were selected (five colonies from each province). Adult bees from these colonies were placed in cages and after introducing mites, damaged mites were collected from each cage every day. The average percentage of injured mites ranged from 0.6 to 3.0% in four provinces. The results did not show any statistical differences between the colonies within provinces for injuries to mites, but there were some differences among province-specific lines. Two kinds of injuries to the mites were observed: injuries to legs and pedipalps, and injuries to other parts of the body. There were also some regular dorsal dimples on dorsal idiosoma of the mites that were placed in categories separate from mites damaged by bees. This type of classification helps identifying damage to mites and comparing them with developmental origin symptoms, and may provide criteria for selecting bees tolerant or resistant to this mite.

Methods for controlling varro mites

Abstract: The present invention relates to methods and compositions comprising spirodiclofen and/ or spiromesifen for the control of bee mites and for the reduction of bee mite infestations, such as the control and reduction of infestations of parasitic bee mites, such as Varroa destructor in bee, preferably honey bee, colonies, and to the treatment of varroatosis in bees.

Epidemiological Study in Varoosis and in other Bees Brood Pathogens in Western Romania

Abstract: Samples of adult bees (Apis mellifera) and bees brood collected from 31 apiaries in western Romania have been examined for diagnosis in varroasis and in bees brood infectious and contagious diseases: ascosferosis, aspergillosis, European foulbrood and American foulbrood. For this study were used rapid immunoassay tests and microscopic examination. Varroa destructor mite was identified in all apiaries, 72% of adult bee samples and 96% of the samples of bees brood was infested. Ascosferosis was identified in 10% of the samples of bees brood and American foulbrood only 2% of the bees brood samples. No cases of aspergillosis and European foulbrood were identified during the study.

Methods for controlling mites

Abstract: The present invention relates to the use of pymetrozine, and salts and compositions thereof, as a miticide, to methods and compositions comprising pymetrozine for the control of bee mites and for the reduction of bee mite infestations, such as the control and reduction of infestations of parasitic bee mites, such as Varroa destructor in bee, preferably honey bee, colonies, and to the treatment of varroatosis in bees.

Biological control of varroa with entomopathogenic fungi : a sustainable solution for a globally important pest?

Abstract: There is a very worrying decline in the number of colonies of the Western honeybee, Apis mellifera, in the northern hemisphere. This comes at a time when the worldwide demand for crops pollinated by bees and other insects is increasing as never before. While no single factor accounts for the loss of all colonies over the world, there is now overwhelming scientific evidence that the varroa mite, Va Varroa destructor, is the primary cause for bee decline in Europe and is a key participant in bee declines in North America. Why is varroa is such a problem and is there a micro biologically based opinion for its management.

Behavioral Defenses of Iranian Honey Bees (Apis mellifera meda)Against Varroa destructor

Abstract: Applying pesticides against Varroa destructor mite in most part of Iranian apiculture is inevitable. Therefore, we tried to investigate the resistance mechanisms of Iranian honeybees (Apis mellifera meda) against Varroa destructor. In this research, records of 50 colonies of the honeybees collected from five different regions of East Azarbayjan province. Recorded traits of each hive were number of adult bees, number of sealed brood, number of mites in phoretic phase, number of Varroa infestation brood, and number of Varroa mites falling on the hive bottom board (major variable). A multiple regression model studied effect of noise variables on the interested major variable. Then, Principal Component Analysis (PCA) was used to survey variables in different regions of apiculture in terms of number of Varroa fallen down on the bottom board of hives together with four above mentioned variables to examine all variables simultaneously. Results of variance analysis showed significance differences among different regions of apiculture in terms of number of Varroa mites down on the hives bottom board. In addition, results of correlation survey indicated that there is no significance correlation between number of the mites on the hive floor and population of adult bees of colonies and number of the sealed brood. However, there is a positive and significance correlation between number of Varroa fallen down on the bottom board of hives and number of mites in phoretic phase (r = 0.575); and number of Varroa infestation brood (r = 0.625). These results indicate the presence of a high variance of resistance behavior against Varroa destructor; and verify the possibility of breeding and producing bees of Iranian honeybee stocks which are resistant against Varroa.

Genetic Basis of Disease Resistance in the Honey Bee ( Apis mellifera L.)

Abstract: Honey bees play a crucial role in pollinating wild and cultivated plants, with substantial implications for our economy and food supply, as well as for natural ecosystems. But the unexplained death of more than one-third of honey bee colonies in North America during each of the past 3 years, termed colony collapse disorder, has endangered the continuous supply of honey bees as pollinators of flowering plants. Among the factors more frequently associated with these die-offs are the ectoparasitic mite Varroa destructor and the endoparasitic microsporidia Nosema apis and Nosema ceranae . Honey bees and their parasites are good models for studies of host–pathogen interactions and disease resistance. This article gives a description of studies conducted during the past several decades that have contributed to our knowledge of specific behavioral and immune-based defenses of honey bees to diseases and parasites. Despite recent advancements at the behavioral level, the study of the genetic basis of disease resistance at the molecular level is still in its infancy and remains poorly understood. More research is needed linking disease resistance traits and candidate genes affecting behavioral and immune-based defenses.

Research regarding bee behavior during the blooming time of melliferous plants.

Abstract: Highly toxic chemicals are widely used in agriculture to combat diseases and pests of crop plants or forest area. This paper aims to demonstrate he impact on the bees of the pesticides treatment used on agricultural entomophilous crops, bees that are their main pollinator. It is also researching measures to protect bee families and humans against poisoning with pesticides. The honey bee has considerable economic importance and is indirectly of great interest, through the benefits it brings to the agricultural field through through crop pollination (rape, mustard, sun flower, etc.).Bees play an important role in the pollination of the most crop batches destined for seed production. From the conducted research, the year 2006 was the most favorable for the bees, because in April, the melliferous plants benefited from better weather conditions, compared to the other years. In the third week after the pesticide treatment, the number of bees has fallen sharply from a maximum of 313 bees recorded in the second week to a minimum of 52 bees in the third week and after another 12 days, after insecticide application, that is, in the fourth week, there was again a maximum of 382 bees. The amount of brood reared in the reference period ranged from 1090 cm 2 and 544 cm 2 and was dependent on the pesticides used in the rape culture and on climate. After the statistical processing of the data a link is observed between the amount of brood as a dependent variable and the number of bees, a proven low value of Pearson correlation coefficients (0.598 to 0.615) and determination of R-Square (0.358-0.378), with the guarantee of experimental results within the acceptable coefficient of 5% given by the Sig. coefficient, i.e. 4%.