Showing papers on "Varroa sensitive hygiene published in 2015"
TL;DR: It is demonstrated for the first time that exposure to field-realistic concentrations of neonicotinoid pesticides during development can severely affect queens of western honey bees and further strengthens the need for stringent risk assessments to safeguard biodiversity and ecosystem services that are vulnerable to these substances.
Abstract: Queen health is crucial to colony survival of social bees. Recently, queen failure has been proposed to be a major driver of managed honey bee colony losses, yet few data exist concerning effects of environmental stressors on queens. Here we demonstrate for the first time that exposure to fieldrealistic concentrations of neonicotinoid pesticides during development can severely affect queens of western honey bees (Apis mellifera). In pesticide-exposed queens, reproductive anatomy (ovaries) and physiology (spermathecal-stored sperm quality and quantity), rather than flight behaviour, were compromised and likely corresponded to reduced queen success (alive and producing worker offspring). This study highlights the detriments of neonicotinoids to queens of environmentally and economically important social bees, and further strengthens the need for stringent risk assessments to safeguard biodiversity and ecosystem services that are vulnerable to these substances.
185 citations
TL;DR: A testable model is developed to explain how multiple factors may be acting synergistically to regulate this complex transition in honey bees in temperate regions and provide suggestions to beekeepers aiming to improve their colonies' overwintering success.
Abstract: In temperate climates, honey bees (Apis mellifera) survive the winter by entering a distinct physiological and behavioral state. In recent years, beekeepers are reporting unsustainably high colony losses during the winter, which have been linked to parasitization by Varroa mites, virus infections, geographic location, and variation across honey bee genotypes. Here, we review literature on environmental, physiological, and social factors regulating entrance, maintenance, and exit from the overwintering state in honey bees in temperate regions and develop a testable model to explain how multiple factors may be acting synergistically to regulate this complex transition. We also review existing knowledge of the factors affecting overwintering survival in honey bees and providing suggestions to beekeepers aiming to improve their colonies’ overwintering success.
126 citations
TL;DR: Comparisons with the antennal transcriptome of nurse and forager bees suggest that VSH profile is more similar to that of nurse bees than foragers, and indicates that antennae likely play a key role in the expression of VSH behaviour.
Abstract: In honey bees, Varroa sensitive hygiene (VSH) behaviour, which involves the detection and removal of brood parasitised by the mite Varroa destructor, can actively participate in the survival of colonies facing Varroa outbreaks. This study investigated the mechanisms of VSH behaviour, by comparing the antennal transcriptomes of bees that do and do not perform VSH behaviour. Results indicate that antennae likely play a key role in the expression of VSH behaviour. Comparisons with the antennal transcriptome of nurse and forager bees suggest that VSH profile is more similar to that of nurse bees than foragers. Enhanced detection of certain odorants in VSH bees may be predicted from transcriptional patterns, as well as a higher metabolism and antennal motor activity. Interestingly, Deformed wing virus/Varroa destructor virus infections were detected in the antennae, with higher level in non-VSH bees; a putative negative impact of viral infection on bees’ ability to display VSH behaviour is proposed. These results bring new perspectives to the understanding of VSH behaviour and the evolution of collective defence by focusing attention on the importance of the peripheral nervous system. In addition, such data might be useful for promoting marker-assisted selection of honey bees that can survive Varroa infestations.
75 citations
TL;DR: A large-scale controlled trial is described, in which different bee pathogens, bee population, and weather conditions across winter were monitored at three locations across the USA, to show that Varroa destructor, along with bee viruses, mainly DWV replication, contributes to approximately 70% of colony losses.
Abstract: Over the last decade, unusually high losses of colonies have been reported by beekeepers across the USA Multiple factors such as Varroa destructor, bee viruses, Nosema ceranae, weather, beekeeping practices, nutrition, and pesticides have been shown to contribute to colony losses Here we describe a large-scale controlled trial, in which different bee pathogens, bee population, and weather conditions across winter were monitored at three locations across the USA In order to minimize influence of various known contributing factors and their interaction, the hives in the study were not treated with antibiotics or miticides Additionally, the hives were kept at one location and were not exposed to potential stress factors associated with migration Our results show that a linear association between load of viruses (DWV or IAPV) in Varroa and bees is present at high Varroa infestation levels (>3 mites per 100 bees) The collection of comprehensive data allowed us to draw a predictive model of colony losses and to show that Varroa destructor, along with bee viruses, mainly DWV replication, contributes to approximately 70% of colony losses This correlation further supports the claim that insufficient control of the virus-vectoring Varroa mite would result in increased hive loss The predictive model also indicates that a single factor may not be sufficient to trigger colony losses, whereas a combination of stressors appears to impact hive health
42 citations
TL;DR: A transient model based on differential equations accounts for the effects of pheromones in slowing the maturation of hive bees to foraging bees, the increased mortality of larvae in the absence of sufficient hive bees, and the effect of food scarcity.
Abstract: Eusocial honey bee populations (Apis mellifera) employ an age stratification organization of egg, larvae, pupae, hive bees and foraging bees. Understanding the recent decline in honey bee colonies hinges on understanding the factors that impact each of these different age castes. We first perform an analysis of steady state bee populations given mortality rates within each bee caste and find that the honey bee colony is highly susceptible to hive and pupae mortality rates. Subsequently, we study transient bee population dynamics by building upon the modeling foundation established by Schmickl and Crailsheim and Khoury et al. Our transient model based on differential equations accounts for the effects of pheromones in slowing the maturation of hive bees to foraging bees, the increased mortality of larvae in the absence of sufficient hive bees, and the effects of food scarcity. We also conduct sensitivity studies and show the effects of parameter variations on the colony population.
41 citations
TL;DR: Australia’s Varroa-free status provides a rare and likely brief window of opportunity for the global bee research community to gain understanding of honey bee-native pollinator community dynamics prior toVarroa invasion.
Abstract: The Varroa mite (Varroa destructor) is implicated as a major disease factor in honey bee (Apis mellifera) populations worldwide. Honey bees are extensively relied upon for pollination services, and in countries such as New Zealand and Australia where honey bees have been introduced specifically for commercial pollinator services, the economic effects of any decline in honey bee numbers are predicted to be profound. V. destructor established in New Zealand in 2000 but as yet, Australia remains Varroa-free. Here we analyze the history of V. destructor invasion and spread in New Zealand and discuss the likely long-term impacts. When the mite was discovered in New Zealand, it was considered too well established for eradication to be feasible. Despite control efforts, V. destructor has since spread throughout the country. Today, assessing the impacts of the arrival of V. destructor in this country is compromised by a paucity of data on pollinator communities as they existed prior to invasion. Australia’s Varroa-free status provides a rare and likely brief window of opportunity for the global bee research community to gain understanding of honey bee-native pollinator community dynamics prior to Varroa invasion.
38 citations
TL;DR: Africanized bees are characterized by presenting higher resistance to V. destructor than European bees, and this study shows that such difference can be, partly due to grooming behavior.
Abstract: The ectoparasitic mite Varroa destructor is one of the main plagues of honey bees Apis mellifera. Grooming behavior is a resistance mechanism through which parasitized bees can dislodge mites by th...
37 citations
TL;DR: The results indicate that exposure to miticides during development severely compromises queen’s reproductive health, and demonstrate the importance of the potentially detrimental combined effects of common in-hive miticides on colony health.
Abstract: The honey bee, Apis mellifera L., plays a pivotal role in the US economy, contributing an estimated $17 billion annually, primarily through crop pollination. Despite their importance, the number of managed honey bee colonies available for pollination services has dropped dramatically during the last decade, threatening crop yields across the country. One of the main culprits of such declines is the varroa mite, Varroa destructor, a pest of honey bees that, when present in high numbers inside a hive, causes colonies to collapse and die. For almost 20 years, varroa mites have been controlled primarily with two in-hive miticides: the pyrethroid tau-fluvalinate (Apistan) and the organophosphate coumaphos (Checkmite+). Various studies have revealed that the exposure of honey bee colonies to sublethal levels of these chemicals can lead to colony-wide health problems. In this study, we looked at the combined effects of fluvalinate and coumaphos on the reproductive health of honey bee queens. We did so by raising...
35 citations
TL;DR: Daily Varroa mite fall decreased over the experimental period with different dynamics in treated and untreated colonies, indicating a minimal benefit of treatment thereby suggesting that A. m.
Abstract: The devastating effects of Varroa destructor Anderson & Trueman on European honeybee colonies (Apis mellifera L.) have been well documented. Not only do these mites cause physical damage to parasitised individuals when they feed on them, they also transmit viruses and other pathogens, weaken colonies and can ultimately cause their death. Nevertheless, not all honeybee colonies are doomed once Varroa mites become established. Some populations, such as the savannah honeybee, A. m. scutellata, have become tolerant after the introduction of the parasite and are able to withstand the presence of these mites without the need for acaricides. In this study, we measured daily Varroa mite fall, Varroa infestation rates of adult honeybees and worker brood, and total Varroa population size in acaricide treated and untreated honeybee colonies. In addition, honeybee colony development was compared between these groups in order to measure the cost incurred by Varroa mites to their hosts. Daily Varroa mite fall decreased over the experimental period with different dynamics in treated and untreated colonies. Varroa infestation rates in treated adult honeybees and brood were lower than in untreated colonies, but not significantly so. Thus, indicating a minimal benefit of treatment thereby suggesting that A. m. scutellata have the ability to maintain mite populations at low levels. We obtained baseline data on Varroa population dynamics in a tolerant honeybee over the winter period. Varroa mites appeared to have a low impact on this honeybee population, given that colony development was similar in the treated and untreated colonies.
34 citations
TL;DR: An integrated strategy for controlling mites that includes chemotherapy and suitable beekeepers management is needed to keep mite populations low during winter.
Abstract: The treatment against Varroa destructor has become a basic tool in beekeeping practices, mainly during autumn. The treatment effectiveness should be improved by identifying variables affecting the final outcome. The aim of this study was to identify the risk factors associated with the treatment outcome achieved during autumn control of Varroa destructor. The mite infestation after treatment was evaluated in 62 apiaries and data regarding management practices were collected by means of a questionnaire. A mixed-effects model was constructed to associate management variables with the risk of treatment failure occurrence. Colonies with high mite levels prior to treatment (P = 0.002) and owned by beekeepers who did not frequently replace queens (P = 0.001) were associated with a higher risk of treatment failure. Other beekeeping practices indirectly improved treatment effectiveness. An integrated strategy for controlling mites that includes chemotherapy and suitable beekeepers management is needed to keep mite populations low during winter.
32 citations
TL;DR: A survival field test was initiated in 1999 to observe the effects of no treatment against Varroa destructor on European honey bee colony survival, and mite populations were very low in 2013.
Abstract: A survival field test was initiated in 1999 to observe the effects of no treatment against Varroa destructor on European honey bee colony survival. After losses of over two-thirds of the 268 original colonies, new colonies were made from the survivors. In 2002, genetic material from these survivors was bred into an independent group of 60 colonies. In 2013, 519 non-treated colonies from both groups were being used for commercial beekeeping, and mite populations were very low. This indicates that under commercial beekeeping conditions, simple methods can be used to select for reduced mite populations.
TL;DR: In this study, RHB colonies showed high levels of hygienic behaviour towards Varroa -infested brood, indicating a stable recombination event before the selection of the VSH stock.
Abstract: Varroa destructor continues to threaten colonies of European honey bees. General hygiene, and more specific Varroa Sensitive Hygiene (VSH), provide resistance towards the Varroa mite in a number of stocks. In this study, 32 Russian (RHB) and 14 Italian honey bee colonies were assessed for the VSH trait using two different assays. Firstly, colonies were assessed using the standard VSH behavioural assay of the change in infestation of a highly infested donor comb after a one-week exposure. Secondly, the same colonies were assessed using an “actual brood removal assay” that measured the removal of brood in a section created within the donor combs as a potential alternative measure of hygiene towards Varroa-infested brood. All colonies were then analysed for the recently discovered VSH quantitative trait locus (QTL) to determine whether the genetic mechanisms were similar across different stocks. Based on the two assays, RHB colonies were consistently more hygienic toward Varroa-infested brood than Italian honey bee colonies. The actual number of brood cells removed in the defined section was negatively correlated with the Varroa infestations of the colonies (r2 = 0.25). Only two (percentages of brood removed and reproductive foundress Varroa) out of nine phenotypic parameters showed significant associations with genotype distributions. However, the allele associated with each parameter was the opposite of that determined by VSH mapping. In this study, RHB colonies showed high levels of hygienic behaviour towards Varroa -infested brood. The genetic mechanisms are similar to those of the VSH stock, though the opposite allele associates in RHB, indicating a stable recombination event before the selection of the VSH stock. The measurement of brood removal is a simple, reliable alternative method of measuring hygienic behaviour towards Varroa mites, at least in RHB stock.
TL;DR: The results are unique for identifying the highest levels of polyandry yet detected that confer colony-level benefit and for showing a benefit ofpolyandry in particular toward the parasitic mite V. destructor.
Abstract: A honey bee queen mates on wing with an average of 12 males and stores their sperm to produce progeny of mixed paternity. The degree of a queen’s polyandry is positively associated with measures of her colony’s fitness, and observed distributions of mating number are evolutionary optima balancing risks of mating flights against benefits to the colony. Effective mating numbers as high as 40 have been documented, begging the question of the upper bounds of this behavior that can be expected to confer colony benefit. In this study we used instrumental insemination to create three classes of queens with exaggerated range of polyandry– 15, 30, or 60 drones. Colonies headed by queens inseminated with 30 or 60 drones produced more brood per bee and had a lower proportion of samples positive for Varroa destructor mites than colonies whose queens were inseminated with 15 drones, suggesting benefits of polyandry at rates higher than those normally obtaining in nature. Our results are consistent with two hypotheses that posit conditions that reward such high expressions of polyandry: (1) a queen may mate with many males in order to promote beneficial non-additive genetic interactions among subfamilies, and (2) a queen may mate with many males in order to capture a large number of rare alleles that regulate resistance to pathogens and parasites in a breeding population. Our results are unique for identifying the highest levels of polyandry yet detected that confer colony-level benefit and for showing a benefit of polyandry in particular toward the parasitic mite V. destructor.
TL;DR: It is observed that infested bees are less involved in tending larvae and dealing with hive duties compared to their uninfested mates, and some hypotheses which could be tested using the infestation method presented here are drawn.
Abstract: Honeybee colonies (Apis mellifera) host a number of parasites, among which the mite Varroa destructor has been implicated in colony losses recorded around the world in recent years. Although many studies have been carried out on the direct and indirect damage caused by the mite to its host, the possible influence of mite infestation on the in-hive behaviour of honeybees has received little attention so far; moreover, to our knowledge, no behavioural study has been performed on adult bees infested during the pupal stage, which is when the mite causes most of its detrimental effects. In order to assess any possible consequence of infestation on the in-hive behaviour of honeybees, we carried out detailed observations on adult bees artificially infested during the pupal stage. We recorded a higher proportion of inactive bees among the infested ones; moreover, we observed that infested bees are less involved in tending larvae and dealing with hive duties compared to their uninfested mates. These results allow to draw some hypotheses which could be tested using the infestation method presented here.
TL;DR: Fumagillin was effective at mitigating Nosema intensities only over the short term, suggesting that biannual application is essential, and V. destructor intensities were higher in colonies that had been previously treated with miticides, reasons for this warrant further investigation.
Abstract: Nosema spp. and Varroa destructor are common parasites of honey bee colonies. Beekeepers routinely treat colonies with the fungicide fumagillin to control Nosema and an array of miticides to control V. destructor. Interactions between these parasites and chemical treatments are poorly understood. We allocated honey bee colonies to distinct chemical treatment regimes and monitored parasite intensities in the subsequent year. Infections of Nosema and infestations of V. destructor were positively correlated. Fumagillin was effective at mitigating Nosema intensities only over the short term, suggesting that biannual application is essential. V. destructor intensities were higher in colonies that had been previously treated with miticides, reasons for this warrant further investigation.
TL;DR: Natural plant compounds (hop acids) as active ingredients for a new veterinary drug for Varroa control proved to be safe for bees and effective against mites, and did not affect the adult bee population and winter survival of colonies.
Abstract: The development of new veterinary medicinal products to control Varroa destructor is very important for the successful management of honey bee colonies. We tested natural plant compounds (hop acids) as active ingredients for a new veterinary drug for Varroa control. Tolerability of bees and efficacy against mites was tested in the laboratory and in the field. In laboratory tests, hop beta acids were proven to be safe for bees (5 % mortality) and effective against mites (93.3 % mortality); there is a six-fold safety margin for bees after individual dermal application compared to the lowest dosage highly toxic to mites. In a clinical study, these results were confirmed: bee colonies tolerated the treatment (<10 % mortality), while most of the mites were killed (efficacy up to 88 %). The treatment did not affect the adult bee population and winter survival of colonies.
TL;DR: It is found that most worker bees do not tolerate the mite on their bodies, and A. m.
Abstract: Grooming behavior by honey bees is regarded as an important trait that contributes to the defense against the parasitic mite Varroa destructor. We carried out an assay to investigate how effective autogrooming by honey bees is in removing V. destructor mites. We compared the behavior of the Carniolan bee (Apis mellifera carnica), represented by two lines: Kortowka and Dobra; the Caucasian bee (Apis mellifera caucasica) of the Woźnica line; the black bee (Apis mellifera mellifera) of the Augustowska line; and the crossbreed of two subspecies: Apis mellifera capensis × A. m. carnica. We found that most worker bees do not tolerate the mite on their bodies. The most intense reaction, manifested by strong motor activity, was observed in A. m. mellifera worker bees; as many as 98% of worker bees in this group made an attempt to remove mites. In the remaining groups, a response was observed in 86% for Caucasian bees to 89.3% for Carniolan bees, Dobra line. The attempts made by bees of different origins to remove...
TL;DR: This study describes a novel observational methodology using infrared camera technology for the long-term, undisturbed investigation of behavioral traits of honey bee, and shows that honey bee workers exhibit a systematic sequence of behavioral activities during the performance of hygienic behavior.
Abstract: Honey bees manifest a rich repertoire of behavioral traits. These traits contribute to the successful establishment of a highly evolved social organization in the honey bee. In this study, we describe a novel observational methodology using infrared camera technology for the long-term, undisturbed investigation of behavioral traits of honey bee. An illustration of this methodology is provided through observations of hygienic behavior in response to varroa infestation. Using our method, we show that honey bee workers exhibit a systematic sequence of behavioral activities during the performance of hygienic behavior. The results of this study support the hypothesis that the uncapping of varroa-parasitized brood cells is driven by abnormal odors from the parasitized pupae.
TL;DR: In this article, the effects of honey bees with different grooming ability and queen pheromone status on mortality rates of Varroa mites (Varroa destructor Anderson and Trueman), mite damage, and mortality rates in honey bees were assessed.
Abstract: The objective of this study was to assess the effects of honey bees (Apis mellifera L.) with different grooming ability and queen pheromone status on mortality rates of Varroa mites (Varroa destructor Anderson and Trueman), mite damage, and mortality rates of honey bees. Twenty-four small queenless colonies containing either stock selected for high rates of mite removal (n = 12) or unselected stock (n = 12) were maintained under constant darkness at 5 °C. Colonies were randomly assigned to be treated with one of three queen pheromone status treatments: (1) caged, mated queen, (2) a synthetic queen mandibular pheromone lure (QMP), or (3) queenless with no queen substitute. The results showed overall mite mortality rate was greater in stock selected for grooming than in unselected stock. There was a short term transitory increase in bee mortality rates in selected stock when compared to unselected stock. The presence of queen pheromone from either caged, mated queens or QMP enhanced mite removal from clusters of bees relative to queenless colonies over short periods of time and increased the variation in mite mortality over time relative to colonies without queen pheromone, but did not affect the proportion of damaged mites. The effects of source of bees on mite damage varied with time but damage to mites was not reliably related to mite mortality. In conclusion, this study showed differential mite removal of different stocks was possible under low temperature. Queen status should be considered when designing experiments using bioassays for grooming response.
11 Feb 2015
TL;DR: Compared the main components of infested and parasite free pupae, harvested from the same colonies, it was found that Varroa mites decreased the mean fresh weight from 124±6.9 to 118±4.1 mg and elevated the intensity of one protein band (50.2 KDa...
Abstract: The impact of parasites on the nutritional value of their hosts may be an important issue that has to be studied in considering insects as future food and feed for humans and animals. The ectoparasite Varroa mite (Varroa destructor) was chosen as an experimental model: it affects bee colonies and largely endangers the honey production. Honey bee (Apis mellifera) brood is largely used as human food in tropical regions and has a great potential to become a future source of proteins and other nutritional and health components, in particular because beekeeping is based on deep knowledge and well developed technologies in great parts of the world. The impact of infestation of Varroa on the nutritive qualities of honey bee brood is barely known. We compared the main components of infested and parasite free pupae, harvested from the same colonies. We found that Varroa mites decreased the mean fresh weight from 124±6.9 to 118±4.1 mg (mean ± standard deviation), elevated the intensity of one protein band (50.2 KDa...
TL;DR: Different diagnostic methods to quantify mite population levels in beehives were evaluated and Recording the number of mites that fell naturally onto the screened bottom board was the only method that showed a significant correlation with the total number of varroa in beEHives.
Abstract: Varroa destructor is the main health problem in Western beekeeping. The quantification of this mite in beehives is an important factor in veterinary inspections and for beekeepers to apply treatments, monitor their success, or assess varroa mite control efforts. In this paper were evaluate different diagnostic methods to quantify mite population levels in beehives: i) mites dislodged with sugar powder and with ethyl alcohol from adult bees samples brushed from honey combs and from brood combs, ii) mites removed from worker brood cells and iii) mite fallen on a screening bottom board for a period of four days. Recording the number of mites that fell naturally onto the screened bottom board was the only method that showed a significant correlation with the total number of varroa in beehives. Quantification in adult bee samples or bee brood samples can only be used for indicative diagnoses. Sugar powder only dislodge a third of the mites from adult bees.
TL;DR: The results indicate that varroa mites were present in all the districts and agroecological regions sampled and bee farmers and beekeeping extension workers were completely unaware of the presence of the varroA mites.
Abstract: Varroa mites are important honey bee ecto-parasites that have caused disaster to the beekeeping industry in Europe and America. The extent of spread of these mites in Africa is not clearly known, but several sub-Saharan African countries including Uganda have been on the varroa-suspect list. We surveyed 16 districts falling in eight agroecological zones in Uganda with the aim of establishing the presence of varroa mites. Within each district, at least two subcounties were visited for honey bee sample collection and varroa detection between September 2011 and April 2013. Honey bee samples collected were screened for varroa mites by dusting with thymol. Farmers and beekeeping extension workers were interviewed on their knowledge of varroa. The results indicate that varroa mites were present in all the districts and agroecological regions sampled. Bee farmers and beekeeping extension workers were completely unaware of the presence of the varroa mites. The farmers reported no changes in honey production and h...
Journal Article•
TL;DR: A relatively shorter capping period of brood cells was observed in one of the provinces compared to others, corresponding with slightly lower mite levels in the same colonies, which might suggest that reducing capping duration may beone of the factors which can potentially affect mite populations in honey bee colonies and therefore should be considered in breeding programs.
Abstract: The aim of this study was to assess infestation levels of Varroa destructor in some honey bee colonies from the National breeding program in the central part of Iran, and the relationship between mite infestation levels and postcapping period (PCP) of worker brood cells. Shortening the PCP is an important parameter limiting the success of varroa mite reproduction in honey bee colonies. In the present study, four pure-bred line colonies from isolated areas were selected to investigate the brood capping durations and mite infestation levels. Cages were used to synchronize egg laying of the queens and the time of capping and emerging of the brood cells was recorded at two-hour intervals. The results did not show any significant differences on the average of PCP of brood cells and mite infestation levels among test colonies. In addition, non-significant correlations were found between mite infestation and the capping period during the experiment. A relatively shorter capping period of brood cells was observed...
Journal Article•
TL;DR: Two important traits that contribute to honey bee (Apis mellifera) colony survival are resistance to varroa and longevity of worker bees and one gene (Orct) is related to improved lifespan in both humans and Drosophila, which provide possible avenues to be pursued for further development for eventual marker-assisted selection.
Abstract: Two important traits that contribute to honey bee (Apis mellifera) colony survival are resistance to varroa and longevity of worker bees. We investigated the relationship between a panel of single nucleotide polymorphism markers and three phenotypic measurements of colonies: (a) percentage of mites in brood (MIB); (b) proportion of fallen injured mites; and (c) longevity of workers. We used single marker analysis to identify genetic intervals that may confer resistance and increased lifespan. One gene related to memory and learning, Ddc was identified for MIB, as was acj6, which functions for olfactory perception. These genes may contribute to elevated levels of mite detection and removal. Three genes were identified with high relevance for mite injury. CYP315A1 and Ptp69D function in motor neuron axon guidance in response to chemical stimuli. RabGAP11 is also involved in sensory function, specifically sensory organ development. Evidence for the longevity quantitative trait locus was also strong and one g...
TL;DR: A mathematical model of the coexistence dynamics of these two species, the bee and the mite, is proposed to analyze the role of resistance behaviors in the overall health of the colony, and, as a consequence, its ability to face epidemiological challenges.
Abstract: Colony Collapse Disorder has become a global problem for bee-keepers and for the crops which depend on bee polination. Multiple factors are known to increase the risk of colony colapse, and the ectoparasitic mite Varroa destructor that parasitizes honey bees is among the main threats to colony health. Although this mite is unlikely to, by itself, cause the collapse of hives, it plays an important role as it is a vector for many viral diseases. Such diseases are among the likely causes for Colony Collapse Disorder. The effects of V. destructor infestation are disparate in different parts of the world. Greater morbidity-in the form of colony losses-has been reported in colonies of European honey bees (EHB) in Europe, Asia and North America. However, this mite has been present in Brasil for many years and yet there are no reports of Africanized honey bee (AHB) colonies losses. Studies carried out in Mexico showed that some resistance behaviors to the mite-especially grooming and hygienic behavior-appear to be different in each subspecies. Could those difference in behaviors explain why the AHB are less susceptible to Colony Collapse Disorder? In order to answer this question, we propose a mathematical model of the coexistence dynamics of these two species, the bee and the mite, to analyze the role of resistance behaviors in the overall health of the colony, and, as a consequence, its ability to face epidemiological challenges.
01 Jan 2015
TL;DR: Population dynamics of Varroa destructor were studied for two years in 20 Apis mellifera intermissa colonies located in Blida (center of Algeria) and the number of bees, the amount of open brood and capped, daily natural mortality, level of infestation of adult bees and level ofinfestation of the brood, was monitored.
Abstract: Population dynamics of Varroa destructor were studied for two years (septembre 2012–2014) in 20 Apis mellifera intermissa colonies located in Blida (center of Algeria). The number of bees, the amount of open brood and capped, daily natural mortality, level of infestation of adult bees and level of infestation of the brood, was monitored.
TL;DR: Rate of invasion of Varroa mite into worker brood cells, the infestation rate on adult worker honeybees, total and effective reproduction rates of the mite in Africanized honeybee colonies under royal jelly or honey production confirm the greater resistance of these honeybees toVarroa destructor than European honeybees.
Abstract: This study evaluated the level of invasion of Varroa mite into worker brood cells, the infestation rate on adult worker honeybees, total and effective reproduction rates of the mite in Africanized honeybee colonies under royal jelly or honey production. Invasion and infestation rates were not statistically different between honeybee colonies producing honey or royal jelly and the averages for these parameters were 5.79 and 8.54%, respectively. Colonies producing honey presented a higher (p < 0.05) total and effective reproduction of Varroa than colonies producing royal jelly. There was a negative correlation between levels of invasion and infestation with minimum external temperature, relative humidity and rainfall. The variables month and season influenced the development of the mite, but rates were low and within the range normally found in Brazil for Africanized honeybee colonies, which confirm the greater resistance of these honeybees to Varroa destructor than European honeybees.
01 Aug 2015
TL;DR: After four years without treatment, the surviving hives of the natural selection apiary showed Varroa infestation rates below the threshold of danger and lower than those in the controlled apiaries.
Abstract: Varroosis of honey bee continues being the main sanitary problem of the apiculture worldwide. The chemical control has been the most used method but it may lead to the development of acaricide resistant mite strains, increases of production costs, toxicity for honeybee and man, and contamination of hive products, with consequent difficulties for its commercialization. In order to know the behaviour of the infestation rates by Varroa mite in untreated hives, adult honeybees and fragments of worker and drone brood combs were sampled monthly from a natural selection apiary for 13 months. As controls, adult honeybees from six conventional apiaries were sampled at different post treatment times. The mean infestation rate by Varroa in not treated hives was: adult honeybees = 3.61% (2.10% - 5.56%), worker brood = 4.89% (1.43% - 15.72%) and drone brood = 34.94% (12.30% - 51.27%). The mean infestation rate in adult bees of the control apiaries was 5.36%. In March and April, when drone brood increases, the higher rates of Varroa destructor infestation were observed in both adult bees and brood. After four years without treatment, the surviving hives of the natural selection apiary showed Varroa infestation rates below the threshold of danger and lower than those in the controlled apiaries.