Varroa-tolerant Italian honey bees introduced from Brazil were not more efficient in defending themselves against the mite Varroa destructor than Carniolan bees in Germany

In Europe and North America honey bees cannot be kept without chemical treatments against Varroa destructor. Nevertheless, in Brazil an isolated population of Italian honey bees has been kept on an island since 1984 without treatment against this mite. The infestation rates in these colonies have decreased over the years. We looked for possible varroa-tolerance factors in six Italian honey bee colonies prepared with queens from this Brazilian island population, compared to six Carniolan colonies, both tested at the same site in Germany. One such factor was the percentage of damaged mites in the colony debris, which has been reported as an indicator of colony tolerance to varroa. A mean of 35.8% of the varroa mites collected from the bottoms of the Italian bee colonies were found damaged, among which 19.1% were still alive. A significantly greater proportion of damaged mites were found in the Carniolan bees (42.3%) and 22.5% were collected alive. The most frequent kind of damage found was damaged legs alone, affecting 47.4% of the mites collected from debris in Italian bees, which was similar to the amount found in Carniolan colonies (46%). The mean infestation rate by the varroa mite in the worker brood cells in the Italian bee colonies was 3.9% in June and 3.5% in July, and in drone brood cells it was 19.3% in June. In the Carniolan honey bee colonies the mean infestation rates in worker brood cells were 3.0 and 6.7%, respectively in the months of June and July and 19.7% in drone brood cells in June. In conclusion, the 'Varroa-tolerant' Italian honey bees introduced from Brazil produced lower percentages of damaged mites (Varroa destructor) in hive debris and had similar brood infestation rates when compared to 'susceptible' Carniolan bees in Germany. In spite of the apparent adaptation of this population of Italian bees in Brazil, we found no indication of superiority of these bees when we examined the proportions of damaged mites and the varroa-infestation rates, compared to Carniloan bees kept in the same apiary in Germany.     

Honey bee colony collapse disorder is possibly caused by a dietary pyrethrum deficiency

Industrialized farming relies on bee keepers transporting hives to the vicinity of large areas of mono-crops for crop pollination. Hives are typically moved multiple times per growing season to satisfy the pollination need. A phenomenon wherein colonies of honey bees collapse in large numbers has been threatening crops in North America. Honey bees are hosts to at least two pathogenic mites; Varroa destructor and Acarapis woodi (a tracheal mite). Pyrethrums are a group of flowering plants which include Chrysanthemum coccineum, Chrysanthemum cinerariifolium, Chrysanthemum marschallii, and related species. These plants produce potent insecticides, also named pyrethrums, which are powerful mite toxins. We believe that a honey bee dietary deficiency of pyrethrums and other micro-nutrients from pyrethrum producing plants allows parasitic mites to either kill the honey bees directly or reduce honey bee resistance to other pathogens. Intermittent feeding of honey bees on pyrethrum producing plants might reverse or prevent colony collapse disorder.     

Genotypic variability and relationships between mite infestation levels, mite damage, grooming intensity, and removal of Varroa destructor mites in selected strains of worker honey bees (Apis mellifera L.)

The objective of this study was to demonstrate genotypic variability and analyze the relationships between the infestation levels of the parasitic mite Varroa destructor in honey bee (Apis mellifera) colonies, the rate of damage of fallen mites, and the intensity with which bees of different genotypes groom themselves to remove mites from their bodies. Sets of paired genotypes that are presumably susceptible and resistant to the varroa mite were compared at the colony level for number of mites falling on sticky papers and for proportion of damaged mites. They were also compared at the individual level for intensity of grooming and mite removal success. Bees from the "resistant" colonies had lower mite population rates (up to 15 fold) and higher percentages of damaged mites (up to 9 fold) than bees from the "susceptible" genotypes. At the individual level, bees from the "resistant" genotypes performed significantly more instances of intense grooming (up to 4 fold), and a significantly higher number of mites were dislodged from the bees' bodies by intense grooming than by light grooming (up to 7 fold) in all genotypes. The odds of mite removal were high and significant for all "resistant" genotypes when compared with the "susceptible" genotypes. The results of this study strongly suggest that grooming behavior and the intensity with which bees perform it, is an important component in the resistance of some honey bee genotypes to the growth of varroa mite populations. The implications of these results are discussed.     

Population growth of Varroa destructor (Acari: Varroidae) in commercial honey bee colonies treated with beta plant acids

Varroa (Varroa destuctor Anderson and Trueman) populations in honey bee (Apis mellifera L.) colonies might be kept at low levels by well-timed miticide applications. HopGuard^® (HG) that contains beta plant acids as the active ingredient was used to reduce mite populations. Schedules for applications of the miticide that could maintain low mite levels were tested in hives started from either package bees or splits of larger colonies. The schedules were developed based on defined parameters for efficacy of the miticide and predictions of varroa population growth generated from a mathematical model of honey bee colony–varroa population dynamics. Colonies started from package bees and treated with HG in the package only or with subsequent HG treatments in the summer had 1.2–2.1 mites per 100 bees in August. Untreated controls averaged significantly more mites than treated colonies (3.3 mites per 100 bees). By October, mite populations ranged from 6.3 to 15.0 mites per 100 bees with the lowest mite numbers in colonies treated with HG in August. HG applications in colonies started from splits in April reduced mite populations to 0.12 mites per 100 bees. In September, the treated colonies had significantly fewer mites than the untreated controls. Subsequent HG applications in September that lasted for 3 weeks reduced mite populations to levels in November that were significantly lower than in colonies that were untreated or had an HG treatment that lasted for 1 week. The model accurately predicted colony population growth and varroa levels until the fall when varroa populations measured in colonies established from package bees or splits were much greater than predicted. Possible explanations for the differences between actual and predicted mite populations are discussed.     

Effects of Imidacloprid and Varroa destructor on survival and health of European honey bees,Apis mellifera

There has been growing concern over declines in populations of honey bees and other pollinators which are a vital part to our food security. It is imperative to identify factors responsible for accelerated declines in bee populations and develop solutions for reversing bee losses. While exact causes of colony losses remain elusive, risk factors thought to play key roles are ectoparasitic mites Varroa destructor and neonicotinoid pesticides. The present study aims to investigate effects of a neonicotinoid pesticide Imidacloprid and Varroa mites individually on survivorship, growth, physiology, virus dynamics and immunity of honey bee workers. Our study provides clear evidence that the exposure to sublethal doses of Imidacloprid could exert a significantly negative effect on health and survival of honey bees. We observed a significant reduction in the titer of vitellogenin (Vg), an egg yolk precursor that regulates the honey bees development and behavior and often are linked to energy homeostasis, in bees exposed to Imidacloprid. This result indicates that sublethal exposure to neonicotinoid could lead to increased energy usage in honey bees as detoxification is a energy‐consuming metabolic process and suggests that Vg could be a useful biomarker for measuring levels of energy stress and sublethal effects of pesticides on honey bees. Measurement of the quantitative effects of different levels of Varroa mite infestation on the replication dynamic of Deformed wing virus (DWV), an RNA virus associated with Varroa infestation, and expression level of immune genes yields unique insights into how honey bees respond to stressors under laboratory conditions.     

The resistance mechanism of the Asian honey bee,Apis cerana Fabr., to an ectoparasitic mite,Varroa jacobsoni Oudemans

A behavioral and physiological resistance mechanism of the Asian honey bee (Apis cerana) to an ectoparasitic mite, Varroa jacobsoni, which causes severe damage to the European honey bee (Apis mellifera) in the beekeeping industry worldwide, is reported here for the first time. Parasitism by the mite induced Asian worker bees to perform a series of cleaning behaviors that effectively removed the mites from the bodies of the adult host bees. The mites were subsequently killed and removed from the bee hives in a few seconds to a few minutes. The grooming behavior consists of self-cleaning, grooming dance, nestmate cleaning, and group cleaning. Worker bees can also rapidly and effectively remove the mites from the brood. The European bee showed cleaning behavior at low frequency and generally failed to remove the mites from both the adult bees and the brood.     

Acaricide treatment affects viral dynamics in Varroa destructor-infested honey bee colonies via both host physiology and mite control

Honey bee (Apis mellifera) colonies are declining, and a number of stressors have been identified that affect, alone or in combination, the health of honey bees. The ectoparasitic mite Varroa destructor, honey bee viruses that are often closely associated with the mite, and pesticides used to control the mite population form a complex system of stressors that may affect honey bee health in different ways. During an acaricide treatment using Apistan (plastic strips coated with tau-fluvalinate), we analyzed the infection dynamics of deformed wing virus (DWV), sacbrood virus (SBV), and black queen cell virus (BQCV) in adult bees, mite-infested pupae, their associated Varroa mites, and uninfested pupae, comparing these to similar samples from untreated control colonies. Titers of DWV increased initially with the onset of the acaricide application and then slightly decreased progressively coinciding with the removal of the Varroa mite infestation. This initial increase in DWV titers suggests a physiological effect of tau-fluvalinate on the host's susceptibility to viral infection. DWV titers in adult bees and uninfested pupae remained higher in treated colonies than in untreated colonies. The titers of SBV and BQCV did not show any direct relationship with mite infestation and showed a variety of possible effects of the acaricide treatment. The results indicate that other factors besides Varroa mite infestation may be important to the development and maintenance of damaging DWV titers in colonies. Possible biochemical explanations for the observed synergistic effects between tau-fluvalinate and virus infections are discussed.     

Gut microbiota composition is associated with environmental landscape in honey bees

There is growing recognition that the gut microbial community regulates a wide variety of important functions in its animal hosts, including host health. However, the complex interactions between gut microbes and environment are still unclear. Honey bees are ecologically and economically important pollinators that host a core gut microbial community that is thought to be constant across populations. Here, we examined whether the composition of the gut microbial community of honey bees is affected by the environmental landscape the bees are exposed to. We placed honey bee colonies reared under identical conditions in two main landscape types for 6 weeks: either oilseed rape farmland or agricultural farmland distant to fields of flowering oilseed rape. The gut bacterial communities of adult bees from the colonies were then characterized and compared based on amplicon sequencing of the 16S rRNA gene. While previous studies have delineated a characteristic core set of bacteria inhabiting the honey bee gut, our results suggest that the broad environment that bees are exposed to has some influence on the relative abundance of some members of that microbial community. This includes known dominant taxa thought to have functions in nutrition and health. Our results provide evidence for an influence of landscape exposure on honey bee microbial community and highlight the potential effect of exposure to different environmental parameters, such as forage type and neonicotinoid pesticides, on key honey bee gut bacteria. This work emphasizes the complexity of the relationship between the host, its gut bacteria, and the environment and identifies target microbial taxa for functional analyses.     

PCR-based detection of a tracheal mite of the honey bee Acarapis woodi

The effects of the tracheal mite Acarapis woodi on the health of honey bees have been neglected since the prevalence of Varroa mites to Apis mellifera colonies. However, tracheal mite infestation of honey bee colonies still occurs worldwide and could impose negative impact on apiculture. The detection of A. woodi requires the dissection of honey bees followed by microscopic observation of the tracheal sacs. We thus developed PCR methods to detect A. woodi. These methods facilitate rapid and sensitive detection of A. woodi in many honey bee samples for epidemiologic surveys.     

Efficacy of strips coated with Metarhizium anisopliae for control of Varroa destructor (Acari: Varroidae) in honey bee colonies in Texas and Florida

Strips coated with conidia of Metarhizium anisopliae (Metschinkoff; Deuteromycetes: Hyphomycetes) to control the parasitic mite, Varroa destructor (Anderson and Trueman) in colonies of honey bees, Apis mellifera (Hymenoptera: Apidae) were compared against the miticide, tau-fluvalinate (Apistan) in field trials in Texas and Florida (USA). Apistan and the fungal treatments resulted in successful control of mite populations in both locations. At the end of the 42-day period of the experiment in Texas, the number of mites per bee was reduced by 69-fold in bee hives treated with Apistan and 25-fold in hives treated with the fungus; however mite infestations increased by 1.3-fold in the control bee hives. Similarly, the number of mites in sealed brood was 13-fold and 3.6-fold higher in the control bee hives than in those treated with Apistan and with the fungus, respectively. Like the miticide Apistan, the fungal treatments provided a significant reduction of mite populations at the end of the experimental period. The data from the broodless colonies treated with the fungus indicated that optimum mite control could be achieved when no brood is being produced, or when brood production is low, such as in the early spring or late fall. In established colonies in Florida, honey bee colony development did not increase under either Apistan or fungal treatments at the end of the experimental period, suggesting that other factors (queen health, food source, food availability) play some major role in the growth of bee colonies. Overall, microbial control of Varroa mites with fungal pathogens could be a useful component of an integrated pest management program for the honey bee industry.     

Microalgae as a promising and sustainable nutrition source for managed honey bees

Managed honey bee colony losses are attributed to a number of interacting stressors, but many lines of evidence point to malnutrition as a primary factor. Commercial beekeepers have become increasingly reliant on artificial pollen substitute diets to nourish colonies during periods of forage scarcity and to bolster colony size before pollination services. These artificial diets may be deficient in essential macronutrients (proteins, lipids, prebiotic fibers), micronutrients (vitamins, minerals), and antioxidants. Therefore, improving the efficacy of pollen substitutes can be considered vital to modern beekeeping. Microalgae are prolific sources of plant-based nutrition with many species exhibiting biochemical profiles that are comparable to natural pollen. This emerging feed source has been employed in a variety of organisms, including limited applications in honey bees. Herein, I introduce the nutritional value and functional properties of microalgae, extrapolating to central aspects of honey bee physiology and health. To conclude, I discuss the potential of microalgae-based feeds to sustainably provision managed colonies on an agricultural scale.     

The effects of temperature and dose of formic acid on treatment efficacy against Varroa destructor (Acari: Varroidae), a parasite of Apis mellifera (Hymenoptera: Apidae)

In order to decrease the variability of formic acid treatments against the honey bee parasite the varroa mite, Varroa destructor, it is necessary to determine the dose-time combination that best controls mites without harming bees. The concentration × time (CT) product is a valuable tool for studying fumigants and how they might perform under various environmental conditions. This laboratory study is an assessment of the efficacy of formic acid against the varroa mite under a range of formic acid concentrations and temperatures. The objectives are 1) to determine the effect of temperature and dose of formic acid on worker honey bee and varroa mite survival, 2) to determine the CT₅₀ products for both honey bees and varroa mites and 3) to determine the best temperature and dose to optimize selectivity of formic acid treatment for control of varroa mites. Worker honey bees and varroa mites were fumigated at 0, 0.01, 0.02, 0.04, 0.08, and 0.16 mg/L at 5, 15, 25, and 35 °C for 12 d. Mite and bee mortality were assessed at regular intervals. Both mite and bee survival were affected by formic acid dose. Doses of 0.08 and 0.16 mg/L were effective at killing mites at all temperatures tested above 5 °C. There was a significant interaction between temperature, dose, and species for the CT₅₀ product. The difference between the CT₅₀ product of bees and mites was significant at only a few temperature-dose combinations. CT product values showed that at most temperatures the greatest fumigation efficiency occurred at lower doses of formic acid. However, the best fumigation efficiency and selectivity combination for treatments occurred at a dose of 0.16 mg/L when the temperature was 35 °C. This revised version was published online in July 2006 with corrections to the Cover Date.     

Russian honey bee (Hymenoptera: Apidae) colonies: Acarapis woodi (Acari: Tarsonemidae) infestations and overwintering survival

Honey bee, Apis mellifera L. (Hymenoptera: Apidae), colonies infested by parasitic mites are more prone to suffer from a variety of stresses, including cold temperature. We evaluated the overwintering ability of candidate breeder lines of Russian honey bees, most of which are resistant to both Varroa destructor Anderson & Trueman and Acarapis woodi (Rennie), during 1999-2001. Our results indicate that Russian honey bee colonies (headed by original and supersedure queens) can successfully overwinter in the north, even during adverse weather conditions, owing to their frugal use of food stores and their resistance to tracheal mite infestations. In contrast, colonies of Italian honey bees consumed more food, had more mites, and lost more adult bees than Russian honey bees, even during unusually mild winter conditions.     

A sequential sampling scheme for detecting infestation levels of tracheal mites (Heterostigmata: Tarsonemidae) in honey bee (Hymenoptera: Apidae) colonies

The introduction of parasitic honey bee mites, the tracheal mite, Acarapis woodi (Rennie) in 1984 and the Varroa mite, Varroa jacobsoni, in 1987, has dramatically increased the winter mortality of honey bee, Apis mellifera L., colonies in many areas of the United States. Some beekeepers have minimized their losses by routinely treating their colonies with menthol, currently the only Environmental Protection Agency-approved and available chemical for tracheal mite control. Menthol is also expensive and can interfere with honey harvesting. Because of inadequate sampling techniques and a lack of information concerning treatment, this routine treatment strategy has increased the possibility that tracheal mites will develop resistance to menthol. It is important to establish economic thresholds and treat colonies with menthol only when treatment is warranted rather than treating all colonies regardless of infestation level. The use of sequential sampling may reduce the amount of time and effort expended in examining individual colonies and determining if treatment is necessary. Sequential sampling also allows statistically based estimates of the percentage of bees in standard Langstroth hives infested with mites while controlling for the possibility of incorrectly assessing the amount of infestation. On the average, sequential sampling plans require fewer observations (bees) to reach a decision for specified probabilities of type I and type II errors than are required for fixed sampling plans, especially when the proportion of infested bees is either very low or very high. We developed a sequential sampling decision plan to allow the user to choose specific economic injury levels and the probability of making type I and type II errors which can result inconsiderable savings in time, labor and expense.     

Single and dual parasitic mite infestations on the honey bee, Apis mellifera L.

Summary: The onset of foraging, proportion of pollen collectors, and weight of pollen loads were compared in individual honey bees (Apis mellifera) infested by zero, one (Acarapis woodi, the honey bee tracheal mite, or Varroa jacobsoni,varroa), or both species of parasitic mites. Phoretic varroa host choice also was compared between bees with and without tracheal mites, and tracheal mite infestation of hosts was compared between bees parasitized or not by varroa during development. The proportion of pollen collectors was not significantly different between treatments, but bees parasitized by both mites had significantly smaller pollen loads than uninfested bees. Mean onset of foraging was earliest for bees parasitized by varroa during development, 15.9 days. Bees with tracheal mites began foraging latest, at 20.5 days, and foraging ages were intermediate in bees with no mites and both, 17.6 and 18.0 days respectively. Phoretic varroa were found equally on bees with and without tracheal mite infestations, but bees parasitized by varroa during development were almost twice as likely to have tracheal mite infestations as bees with no varroa parasitism, 63.9 % and 35.5 %, respectively. These results indicate that these two parasites can have a biological interaction at the level of individual bees that is detrimental to their host colonies.     

Varroa destructor infestation in untreated honey bee (Hymenoptera: Apidae) colonies selected for hygienic behavior

Honey bee (Apis mellifera L.) colonies bred for hygienic behavior were tested in a large field trial to determine if they were able to resist the parasitic mite Varroa destructor better than unselected colonies of"Starline" stock. Colonies bred for hygienic behavior are able to detect, uncap, and remove experimentally infested brood from the nest, although the extent to which the behavior actually reduces the overall mite-load in untreated, naturally infested colonies needed further verification. The results indicate that hygienic colonies with queens mated naturally to unselected drones had significantly fewer mites on adult bees and within worker brood cells than Starline colonies for up to 1 yr without treatment in a commercial, migratory beekeeping operation. Hygienic colonies actively defended themselves against the mites when mite levels were relatively low. At high mite infestations (>15% of worker brood and of adult bees), the majority of hygienic colonies required treatment to prevent collapse. Overall, the hygienic colonies had similar adult populations and brood areas, produced as much honey, and had less brood disease than the Starline colonies. Thus, honey bees bred for hygienic behavior performed as well if not better than other commercial lines of bees and maintained lower mite loads for up to one year without treatment.     

Maize pollen foraging by honey bees in relation to crop area and landscape context

The increasing demand for insect pollinated crops and high recent losses of honey bee colonies raise concerns about food security. Systemic insecticides are recognized as one of the drivers of worldwide honey and wild bee declines. Particularly honey bees in agricultural environments are exposed to pesticides when they collect crop pollen and nectar. However, landscape scale studies which analyze pollen use and foraging distances of honey bees on mass-flowering crops like maize to evaluate potential exposure risks are currently lacking. In an experimental approach on a landscape scale we took advantage of intra-colonial dance communication to gather information about the location of utilized pollen resources. During maize flowering, four observation hives were placed in and rotated between 11 different landscapes which covered a gradient from low to high maize acreage. A higher frequency of dances for foraging locations on maize fields compared to other land use types shows that maize is an intensively used pollen resource for honey bee colonies. Mean foraging distances were significantly shorter for maize pollen than for other pollen origins. The percentage of maize pollen foragers did not increase with maize acreage in the landscape. The proportion of grassland area providing alternative pollen sources did not reduce the percentage of maize pollen foragers. Our findings allow estimating the distance-related exposure risk of honey bee colonies to pollen from surrounding maize fields treated with systemic insecticides. Similarly, the results can be used to estimate the exposure to transgenic maize pollen, which is relevant for honey production in European countries. Provision of alternative pollen resources within agri-environmental schemes could potentially reduce exposure risk to pesticide contaminated crop pollen.     

Direct effect of acaricides on pathogen loads and gene expression levels in honey bees Apis mellifera

The effect of using acaricides to control varroa mites has long been a concern to the beekeeping industry due to unintended negative impacts on honey bee health. Irregular ontogenesis, suppression of immune defenses, and impairment of normal behavior have been linked to pesticide use. External stressors, including parasites and the pathogens they vector, can confound studies on the effects of pesticides on the metabolism of honey bees. This is the case of Varroa destructor, a mite that negatively affects honey bee health on many levels, from direct parasitism, which diminishes honey bee productivity, to vectoring and/or activating other pathogens, including many viruses. Here we present a gene expression profile comprising genes acting on diverse metabolic levels (detoxification, immunity, and development) in a honey bee population that lacks the influence of varroa mites. We present data for hives treated with five different acaricides; Apiguard (thymol), Apistan (tau-fluvalinate), Checkmite (coumaphos), Miteaway (formic acid) and ApiVar (amitraz). The results indicate that thymol, coumaphos and formic acid are able to alter some metabolic responses. These include detoxification gene expression pathways, components of the immune system responsible for cellular response and the c-Jun amino-terminal kinase (JNK) pathway, and developmental genes. These could potentially interfere with the health of individual honey bees and entire colonies.     

Reproductive biology of <Emphasis Type="Italic">Varroa destructor</Emphasis> in Africanized honey bees (<Emphasis Type="Italic">Apis mellifera</Emphasis>)

Since its first contact with Apis mellifera, the population dynamics of the parasitic mite Varroa destructor varies from one region to another. In many regions of the world, apiculture has come to depend on the use of acaricides, because of the extensive damage caused by varroa to bee colonies. At present, the mite is considered to contribute to the recent decline of honey bee colonies in North America and Europe. Because in tropical climates worker brood rearing and varroa reproduction occurs all year round, it could be expected that here the impact of the parasite will be even more devastating. Yet, this has not been the case in tropical areas of South America. In Brazil, varroa was introduced more than 30 years ago and got established at low levels of infestation, without causing apparent damage to apiculture with Africanized honey bees (AHB). The tolerance of AHB to varroa is apparently attributable, at least in part, to resistance in the bees. The low fertility of this parasite in Africanized worker brood and the grooming and hygienic behavior of the bees are referred as important factors in keeping mite infestation low in the colonies. It has also been suggested that the type of mite influences the level of tolerance in a honey bee population. The Korea haplotype is predominant in unbalanced host-parasite systems, as exist in Europe, whereas in stable systems, as in Brazil, the Japan haplotype used to predominate. However, the patterns of varroa genetic variation have changed in Brazil. All recently sampled mites were of the Korea haplotype, regardless whether the mites had reproduced or not. The fertile mites on AHB in Brazil significantly increased from 56% in the 1980s to 86% in recent years. Nevertheless, despite the increased fertility, no increase in mite infestation rates in the colonies has been detected so far. A comprehensive literature review of varroa reproduction data, focusing on fertility and production of viable female mites, was conducted to provide insight into the Africanized bee host-parasite relationship.     

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

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.