Journal of Apicultural Research

Published by International Bee Research Association
Online ISSN: 2078-6913
Print ISSN: 0021-8839
Chalkbrood and stonebrood are two fungal diseases associated with honey bee brood. Chalkbrood, caused by Ascosphaera apis, is a common and widespread disease that can result in severe reduction of emerging worker bees and thus overall colony productivity. Stonebrood is caused by Aspergillus spp. that are rarely observed, so the impact on colony health is not very well understood. A major concern with the presence of Aspergillus in honey bees is the production of airborne conidia, which can lead to allergic bronchopulmonary aspergillosis, pulmonary aspergilloma, or even invasive aspergillosis in lung tissues upon inhalation by humans. In the current chapter we describe the honey bee disease symptoms of these fungal pathogens. In addition, we provide research methodologies and protocols for isolating and culturing, in vivo and in vitro assays that are commonly used to study these host pathogen interactions. We give guidelines on the preferred methods used in current research and the application of molecular techniques. We have added photographs, drawings and illustrations to assist bee-extension personnel and bee scientists in the control of these two diseases.
Average loss experienced by all responding beekeepers who managed bees in one or more than one state.
Average loss in operations reporting and not reporting various factors as a major reason for colony mortality. Only those operations that responded to the appropriate question are represented.
This study records the third consecutive year of high winter losses in managed honey bee colonies in the USA. Over the winter of 2008-9 an estimated 29 % of all US colonies died. Operations which pollinated Californian almond orchards over the survey period had lower average losses than those which did not. Beekeepers consider normal losses to be 17.6 %, and 57.9 % of all responding beekeepers suffered losses greater than that which they considered to be acceptable. The proportion of operations with the Colony Collapse Disorder (CCD) symptom of "no dead bees in the colony or apiary" decreased in this period as compared to the previous years. The proportion of colonies dying from apparently manageable conditions, however, such as starvation or a weak condition in the fall increased as compared to previous surveys.
Although the hypopharyngeal glands of overwintering worker honeybees (Apis mellifera) are hypertrophied, glands isolated from such bees were found to display low rates of protein synthesis in vitro. In the presence of brood, protein synthesis was activated to a maximum within 3 days; in the absence of brood, however, neither pollen consumption nor juvenile hormone treatment of workers stimulated protein synthesis. When the colony was transferred to a flight room, workers' hypopharyngeal glands remained activated for several weeks while the first brood was being reared. Later, only newly emerged bees were involved in rearing brood.
Commercially available pollen substitute diets for honey bees (Apis mellifera L.) were evaluated for consumption and colony growth (brood and adult populations) and compared with pollen cake and high fructose corn syrup (HFCS). Two trials were conducted; the first for 3 months during the fall and winter and a second for 2 months in the summer. Three diets were tested in Trial 1 (Diet-1, Diet-2, and Diet-3 (liquid and patty form)) and Diet-2 and Diet-3 (patty) in Trial 2. In both Trials, Diet-2 and Diet-3 patty were consumed at rates that were comparable to pollen cake. Colonies consumed significantly less Diet-1 than the other diets. There was a significant relationship between the amount of diet consumed and the change in brood area and adult population size in both Trials. Colonies fed Diet-3 patty produced significantly more brood than those fed pollen cake or any other diet in Trial 1. The lowest brood production occurred in colonies fed Diet-1 or HFCS. Adult populations in colonies fed Diet-3 liquid or patty did not differ from those fed pollen cake, and were significantly larger than colonies fed Diet-1 or Diet-2. In Trial 1, when some pollen was being collected by colonies, Diet-2 and Diet-3 did not differ from pollen cake in brood or adult population growth.
body length, width and weight (mean ± SE) of newly-emerged adults of Aethina tumida reared individually inside the incubator and at room temperature. 
The effects of temperature on several life history parameters of small hive beetles (SHB), Aethina tumida, were investigated under laboratory conditions. Our results showed that the development, body size and weight of SHB were dependent on temperature. Egg incubation was about two days at higher temperature (34°C) and three days at lower (room) temperature (24-28°C). Exposure of larvae to lower temperature resulted in a 15-day extension to their development to adult emergence with a mean of 36.31 ± 0.08 days as opposed to 20.68 ± 0.08 days at higher temperature (34°C). At lower temperature, the developmental time (first instar to adult emergence) of males was about one-half day longer (36.63 ± 0.12 days) than that of females (36.02 ± 0.15 days). Higher temperature supported larger (length = 6.30 ± 0.07mm, width = 3.48 ± 0.02mm) and heavier (12.95 ± 0.22mg) adult females than did the lower temperature (length = 5.30 ± 0.04mm, width = 3.39 ± 0.02mm, weight = 11.40 ± 0.20mg). Weight and width similarities between males exposed to higher temperature (weight = 11.53 ± 0.14 mg, width = 3.43 ± 0.02mm) and females reared under room temperature (weight = 11.40 ± 0.20mg, width = 3.39 ± 0.02mm) were also observed. From this study, we can deduce that the abundance and impact of SHB on honey bee colonies may be influenced by their rate of development in different thermic regimes. A new technique for rearing individual SHB is also described.
Honey bee colony infestation by the small hive beetle (SHB) is associated with fermentation of hive materials. Pollen, beetles, and robbing bees (ten of each) were collected from hives infested with SHB in both Florida and Kenya. Plating of homogenized bodies of beetles and bees and comb swabs resulted in smooth cream-colored yeast colonies that formed pseudomycelial cells as they aged. Fatty acid profiles of yeast isolates from Florida and Kenya most closely matched the profiles of Candida krusei and C. sake, respectively. The DNA sequence of the 28S and 5.8S-ITS2 of both the Florida and Kenya isolates were, however, 99-100 % homologous to Kodamaea ohmeri. The ITS1 region differed between the two geographic strains. The two strains produced similar volatile profiles which were attractive to SHB and contained compounds also found in honey bee alarm pheromone.
The guard age and duration of European (Apis mellifera) and Cape (A. m. capensis) honey bees guarding small hive beetles (Aethina tumida) were determined using 3-frame observation hives, noting the commencement and termination of beetle guarding by individually labelled honey bees. European honey bees in the USA began guarding small hive beetles significantly earlier (beginning age 18.55 ± 0.52 days; mean ± s.e.), guarded beetles significantly longer (duration 2.36 ± 0.31 days), and stopped guarding beetles significantly sooner (ending age 19.91 ± 0.57 days) than Cape honey bees in South Africa (beginning age 20.61 ± 0.38 days; duration 1.43 ± 0.12 days; and ending age 21.04 ± 0.37 days). Although the timing of beetle guarding behaviour between the two subspecies is significantly different, it does not explain the differential damage to European and Cape honey bee colonies caused by small hive beetles.
The small hive beetle (SHB) is a parasite and scavenger of honey bee colonies, but may also be able to exploit alternative food sources. We conducted experiments to shed further light on the role of alternative foods for SHB. 1) Laboratory choice experiments showed that adult SHB oviposit on fruit and even on decaying meat and that SHB larvae feed on it despite the presence of bee products. 2) In the laboratory, SHB reproduced on mango, banana and grapes at lower rates than on a pollen and honey mixture. 3) Adult SHB were rarely observed on fruit buckets in the field. They reproduced only when caged and in much smaller numbers than Drosophilidae and other Nitidulidae. 4) While Aethina concolor was repeatedly observed during a field survey, no adult SHB were found on any flowers. 5) Less than 2% of adult SHB survived on blooming pot plants and no reproduction was recorded, suggesting that flowers are unlikely to serve as an alternative food and breeding substrate. Nevertheless, the high degree of opportunism displayed, supports the view that honey bee nests are not essential for SHB survival and reproduction. Despite the observed high degree of SHB opportunism, it appears as if alternative food sources play a minor role only for reproduction in the field when host colonies are available. Even though SHB may use alternative food sources in the absence of bee hives (e.g. after migratory beekeeping), it is unclear whether this is likely to contribute to SHB population build up.
The response of Russian honey bees to brood infested with small hive beetle (SHB) eggs and larvae was compared to that of a commercial stock (predominantly of A. m. ligustica). Test brood was grouped as follows: a) NoP = no perforation either of capping or cell wall; b) PWall = perforation of cell wall only; c) PCap = perforation of capping only; and d) PBoth = capping and cell wall perforations. All perforations were made by SHB. Our results showed that brood cells with perforations of the cell wall (PWall and PBoth) had the highest infestation (76.53 ± 2.10%) and number of eggs (58.46 ± 2.85 eggs). Because PCap showed low levels of infestation (29.17 ± 3.31% and 15.60 ± 1.31 eggs per infested cell), we calculated brood removal based on data from PWall and PBoth groups. Within 6 h, both stocks removed the contents of 39.24 ± 4.94% of PWall cells. A higher removal rate of 50.51 ± 5.80% was observed in PBoth cells. These two groups of brood had the highest numbers of eggs per infested cell (50-70 eggs). Eggs hatched after the 6 h observation and subsequent hygienic removal was of brood infested with larvae. At 20 h, additional 56.41 ± 4.62% (PWall) and 42.04 ± 4.91% (PBoth) removal rates were observed. Overall, the cumulative removal rates for both stocks were similar with means of 85.11 ± 2.98% and 84.32 ± 4.29% for the commercial and Russian honey bees, respectively. In conclusion, we observed that both honey bee stocks were able to detect eggs inside the sealed brood cells and remove them with the infested brood.
Average number of adult SHB per colony regardless of honey bee strain from 2005 to 2008 for Site 1. Bars with different letters are significantly different (P < 0.05). Colony divisions were made in July 2004, but beetle counts began in February 2005.
Average number of adult SHB per colony regardless of honey bee strain from 2005 to 2008 for Site 2. Bars with different letters are significantly different (P < 0.05). Colony divisions were made in July 2004, but beetle counts began in February 2005. * By April 2008 the majority of the queens in the colonies had been superseded and were not included in the analysis thereby making the data too small to accurately compare with the others.
Average number of adult SHB per colony as affected by the proportion of hot days over time.
The population of small hive beetles, Aethina tumida (SHB), was monitored from 2005 to 2008 in colonies of Italian and Russian honey bees located near St. Gabriel, Louisiana, USA. SHB populations differed between honey bee strains (only in one site out of two), with Italian colonies supporting more beetles (7.45 ± 0.98 SHB per colony) than the Russian colonies (4.48 ± 0.51 SHB per colony). No difference between the two strains was observed at site 1 where the SHB population was generally low (Italian = 2.73 ± 0.36 SHB; Russian = 2.69 ± 0.57 SHB per colony). Our results also revealed that SHB populations varied throughout the year, with peak infestations observed in the autumn (September and November). SHB abundance was significantly correlated with the proportion of hot days, but not with the proportions of cool, dry, or humid days, or the percentage of days with rainfall. Our results suggest that in-hive autumn trapping of SHB in the south eastern USA may reduce springtime numbers of SHB.
The volumes of brains and major brain regions were compared between European (EHB) and African (AHB) honey bee workers. The brain volume was not significantly different between the two bee races. The overall composition of major brain regions appeared similar except for the lobes of the mushroom bodies, which were significantly larger in EHB. Discriminant analysis indicated that brains from EHB could be distinguished from those of AHB based on the volumes of the central body together with either the mushroom body lobe or the mushroom body calyx. Whether learning and memory capacities differ between AHB and EHB based on the size of mushroom body lobes and whether the differences are adaptive due to the environments where EHB and AHB originated are discussed.
From February to July 2001, the reproductive ability of Varroa destructor in artificially infested worker brood cells of Africanized honey bees (AHB) (Apis mellifera) and hybrids (HF1) of AHB x European honey bees was investigated in Costa Rica. No significant differences were found between AHB and HF1 in the percentage of fertile foundress mites (AHB = 69.8%, HF1 = 76.5%), the percentage of foundress mites that produced mature female offspring (AHB = 28%, HF1 = 25.4%), the mean number of offspring per foundress (AHB = 3.4, HF1 = 3.5) and the percentage of foundress mites that produced only immature stages (AHB = 17.3%, HF1 = 18.2%). Nevertheless, the percentage of foundress mites that did not reproduce at all tended to be greater in AHB than in HF1 colonies (AHB = 30.2%, HF1 = 23.5%; P = 0.06). In both groups of bees, the number of fertile varroa mites was higher than that reported in other studies for AHB in Brazil (49-55%). Furthermore, the percentage of non-reproducing mites was greater than the percentage reported for mites in European bees and lower than the percentage reported for mites in AHB in Brazil. Thus, the AHB population we monitored in this study may be less tolerant to varroa than AHB populations in Brazil.
The collection of pollen by high and low alfalfa pollen collecting lines of honeybees was studied at Baton Rouge, Louisiana, where no alfalfa (Medicago sativd) is grown. The high line collected significantly more pollen than the low line from Trifolium repens, Cornus drummondii, Ampelopsis arborea, Polygonum spp., Lippia lanceolata and Geranium carolinianum. The low line collected significantly more than the high line from Tradescantia bracteata, Rhus radicans, Ambrosia spp. and Solidago spp. Twenty-four pollen sources were studied.
Four groups of honeybees were tested for their tendency to collect alfalfa pollen in south-western Idaho (where honeybees do not normally collect alfalfa pollen) and in northern Utah (where they do). In the seventh generation of the line with a strong tendency to collect alfalfa pollen (high line), the percentage of pollen collectors returning to the hive with alfalfa pollen was 35·6 % in Idaho and 87·4 % in Utah; the average percentage in the line with a low tendency to collect alfalfa pollen (low line) was 9·9% in Idaho and 36·4% in Utah. The percentages of alfalfa pollen collectors in the two mating groups of line B (an unrelated strain) occupied an intermediate position, at 15·7 and 17·7% respectively in Idaho and 77·0 and 64·1 % in Utah.In Idaho, the high line possessed the highest mean number of alfalfa pollen collectors per sample (15); line B (average for both groups) had an intermediate number (9); and the low line the lowest (4). In Utah, the three corresponding groups of colonies occupied the same positions in relation to the mean number of alfalfa pollen collectors per sample, but there was much less difference between them (respectively, 18, 14 and 13). The yield of honey was greatest from the line B colonies, which were the least inbred.
Morphometric analyses of Apis florea F. in Thailand were carried out in order to detect differences within this species. The nine body parts selected for analysis were: proboscis, antenna, forewing, hindwing, hind leg, the third and sixth sternites, and the third and fourth tergites. Twenty-two characters, consisting of widths, lengths or angles, were measured. Factor analysis sorted 14 characters of worker bees into four factors. Factor 1: characters associated with size, hind leg and antenna; Factor 2: length of wing venation and forewing; Factor 3: number of hamuli and venation angle 37; and Factor 4: venation angle 34. The results of factor and cluster analyses using these 22 characters revealed that the A. florea of Thailand are distributed as one group. Four characters: forewing radial cell length, metatarsus length, 3rd sternite length and antenna length; can be used to separate the A. florea of Samui and Pha-ngan Islands from the mainland samples by Student'Newman'Keuls Statistics.
Essential oils were fed to honey bees to determine whether the components were absorbed into bee larvae. The oils were added in either sucrose syrup (origanum and 2-heptanone) or in a liquid protein diet (origanum oil, cinnamon oil, thymol, and 2-heptanone), because sugar and protein sources are differentially utilized in food fed to larvae of different ages. The volatiles emitted by isolated larvae from oilsupplemented colonies were sampled at three different ages (Day 4, Day 6 and Day 9) by Solid Phase Micro-Extraction (SPME) and analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). The only oil volatiles recovered in larvae were the origanum oil components carvacrol and thymol; neither 2-heptanone nor the cinnamon oil components were detected in any larvae. For larvae from colonies fed oilsupplemented sugar syrup, carvacrol volatiles were emitted at higher amounts in younger larvae (Day 4) than in older larvae (Day 9). In contrast, carvacrol and thymol volatiles were detected only in older larvae (Day 6 and Day 9) in colonies reared on oil-supplemented liquid protein diet. Carvacrol was also detected in the cocoons of Day 9 larvae from colonies fed oil-supplemented liquid protein diet, but not oilsupplemented sugar syrup diet. We believe that the age-related differences in oil incorporation by bee larvae reflect the relative importance of supplemental sugars and protein as food sources for bee larvae of these ages. Supplementation in a liquid protein diet represents a more efficacious route for the incorporation of origanum oils in fifth instar bee larvae targeted for invasion by Varroa destructor mites.
In 20 colonies of Apis cerana in northern Vietnam, colony growth, production of drones and queens (sexuals), and swarming and supersedure were related to available flower forage and climate. Despite the tropical setting of the study with year-round forage, production of sexuals was restricted to two periods from March to July and from September to December. Most swarming occurred in May when forage was most abundant. Positive correlations between available forage, colony growth, and production of sexuals suggest that the synchronized production of drones and queens is defined by nutrient flow into the colony. If flow is high, the colony starts growing; when the colony is large enough drones and queens are produced, and eventually the colony swarms. Production of sexuals is synchronized because foraging conditions are sufficient to allow growth for only part of the year. Patterns in drone and queen rearing by A. cerana are similar to patterns found in Apis mellifera. Variation may reflect differences in environment and between species
In order to decipher the assumed scent signals from diploid drone larvae which release the cannibalism behaviour of nursing worker honey bees, cuticular extracts of newly hatched and unfed live larvae were made by brief washes in pentane. The first instars were sexed using a recently improved method. The extracted cuticular substances of diploid drones, diploid workers and haploid drones were analysed by gas chromatography-mass spectrometry. Greater quantities of cuticular compounds were obtained from male than from female larvae, with the diploid drones having a little less than the haploids. The main components in the first instar larval spectrum were identified as four alkanes and squalene, present in the extracts of all three larval types, but in different amounts. No substance was found to occur exclusively on the diploid drones. Our analyses clearly indicate pronounced quantitative but no qualitative peculiarities in the pattern of cuticular secretions on first instar diploid drone larvae. The pattern differs from both the worker and the normal drone composition and is presumably perceived as odd by the nursing worker bees. This assumption was bioassayed with dummies impregnated with blends copying the quantitative pattern of the five main components as determined for the three types of larvae. The brood cells containing diploid drone 'dummies' (shaped from paraffin) were emptied significantly faster than those with the worker and haploid drone odour or the controls. According to these within-colony test results, the adult bees can recognize diploid drones by their particular pattern of cuticular secretions. Neither the previous notion of a cannibalism substance nor that of a diminished production of pheromones could be confirmed. Implications of this infanticide on inclusive fitness of the superorganism bee colony and evolutionary aspects in relation to the hymenopteran sex determination are discussed.
Biotechnical methods of varroa (Varroa jacobsoni) control are based on the idea that mites inside brood cells are trapped and can then easily be removed from a honey bee (Apis mellifera) colony. Trapping is most efficient using drone brood in otherwise broodless colonies. In theory, one trap-comb with drone brood is enough to achieve control. We designed and tested two methods using trap-combs with drone brood. In the first experiment, effectiveness of the control method varied considerably, from 67% to 96%. However, the observed effectiveness in each separate colony was similar to the prediction based on knowledge of behaviour of mites invading brood cells. Effectiveness depended on the number of drone cells that had been available for mite trapping. In the second experiment, we adjusted the method to improve production of trap-combs with drone brood, since this appeared to be crucial for trapping efficiency. The observed effectiveness of 93.4% demonstrates that trap-combs with drone brood can effectively trap mites, thereby offering a non-chemical method of varroa control. The use of knowledge on invasion behaviour of mites for evaluating trap-comb methods and modelling varroa population dynamics is discussed.
Biotechnical varroa (Varroa jacobsoni) control methods are based on the principle that mites inside brood cells are trapped and then removed from the bee colony. In our experiments trapped mites were killed with formic acid. Worker brood used for trapping was retained and returned to the colonies. The observed percentage of mites trapped and killed by formic acid treatment was 87% and 89% in two experiments. The effectiveness could be predicted using prior knowledge on brood cell invasion behaviour, which thus proved to be valid for the design and improvement of trap-comb methods for ecological varroa control.
As a preliminary to the use of bumble bee colonies in greenhouse pollination in Turkey, research was initiated on the relevant characteristics of the native bumble bee Bombus terrestris dalmatinus. The same methodology was used that has been successful in the rearing of B. t. terrestris colonies. Queens were collected in four coastal localities (Bodrum, Antalya, Alata and Adana) and characterized by the different dates of the young queen's emergence from diapause. This emergence varied from the end of November to February. Despite the variation in collecting dates, the patterns of development of the colonies produced were similar, indicating that, in this respect, no ecotypes existed. As in B. t. terrestris, the relative timing of the switch point, i.e. when mainly haploid eggs are laid by the queen, is the determining factor for the number of workers and the investment sex ratio of the B. t. dalmatinus colonies. The colonies of these two subspecies develop according to the same principles. The colonies from all four regions had, on average, a male-biased investment sex ratio (0.21, queen fraction), which is a common feature for bumble bees. On the basis of the number of workers produced (c. 150 workers), the colonies from these four Turkish areas are very well suited for pollination purposes.
The pollen component of the larval food of Colletes halophilus, studied in four nature reserves in the Netherlands, was strongly dominated by Aster tripolium. The liquid component of the larval food contained high concentrations of sugars (glucose and fructose), far more than could be supplied by A. tripolium pollen present in the food. This indicates that in addition to pollen, considerable amounts of nectar were collected from this plant. The larval food showed hydrogen peroxide production. We did not, however, find this in pollen collected directly from A. tripolium flowers. We conclude that females of C halophilus produce the enzyme glucose oxidase and add this to larval food. This is the first such finding for solitary bees. The apparent dependency of C halophilus on A. tripolium has implications for the conservation management of this solitary bee.
In honey bees, both the allocation of foragers to pollen collecting and the behaviour of the pollen foragers depends on the colony's need for pollen, the mortality rate of foragers and the input of information regarding pollen availability in the field. The response of stingless bees to these factors is not known. Therefore, we studied the response of Melipona beecheii to experimental pollen deprivation, worker loss and controlled information input. Following pollen stress M. beecheii did not increase its forager force, but allocated more foragers to pollen foraging. There was an indication that individual foraging was intensified. During the first 10 days after the reduction of the pollen reserve, pollen availability in the field was low and pollen foraging almost stopped. The increase in pollen foraging occurred after these 10 days. M. beecheii did not respond to daily variation in worker mortality or experimentally induced 50% worker loss. Behaviour of pollen foragers was related to previous day foraging experience and not to colony foraging parameters such as the total number of pollen loads and the size of the work force. More foragers were allocated to pollen foraging when more information on pollen availability (returning successful foragers) came into the hive. This study indicates that in M. beecheii the allocation of foragers to pollen collecting depends both on the availability of pollen sources and on colony needs. Their response to pollen stress was similar to that reported for Apis mellifera, except for the more conservative response to low pollen availability in the environment. This conservative reaction may be typical for stingless bees, that due to the mass provisioning of brood cells, do not suffer immediate brood loss when pollen is lacking.
Map showing states of the USA and regions of Italy from which samples of Italian honey bees were obtained for genetic analysis.  
Microsatellite allele frequencies at 6 loci used in genetic diversity analyses of Italian honey bees in the USA and Italy. Loci are grouped according to repeat unit length as follows: A) trinucleotide repeats, B) tetranucleotide repeat.  
Neighbour-joining phenogram of Italian bees in the USA and Italy. The phenogram was generated from chord distances (Cavalli-Sforza and Edwards, 1967) based on genotypes of 6 microsatellite loci. Letters represent queen breeders from which samples were collected.  
Summary Declines in the numbers of breeder honey bee queens and the concomitant loss of genetic diversity could potentially result in inbreeding, and increased susceptibility to pests and diseases. Genetic diversity of commercial Italian bee colonies in the United States and Italy was assessed using six variable microsatellite DNA loci. Worker bees were sampled from colonies of queen breeders in both countries (USA, n = 18; Italy, n = 24). Overall, allelic richness (mean alleles/locus), gene diversity (heterozygosity), and FIS (inbreeding coefficient) did not differ between the two groups. A total of 48 alleles were present among all colonies. Sampled colonies from each country had a total of 38 alleles, although alleles were present that were unique to each group. There were a total of 10 unique alleles among USA bees and 10 among Italian bees. Estimates of the level of genetic differentiation based on different allele frequency patterns among the USA and Italian bees were measured with the population genetic parameter FST. These estimates showed that bees from the USA and Italy were measurably distinct relative to the frequencies of the microsatellite alleles present in samples from each country. Overall allelic diversity levels were sufficiently high indicating that inbreeding does not appear to be an immediate threat to existing honey bee populations.
Mite resistance that we had earlier called suppression of mite reproduction (SMR) is a form of hygienic behaviour that we have named Varroa Sensitive Hygiene (VSH). With VSH, adult worker bees (Apis mellifera) disrupt the reproduction of parasitic mites (Varroa destructor) by removing mite infested bee pupae from their cells. This study determines which brood cells are targeted by bees with VSH and which are not, and describes the relationship between brood removal and the sudden prevalence of sterile mites. We produced 26 colonies with different levels of VSH by backcrossing 14 queens from a high line, H (100% expression of VSH), and 12 queens from a low line, L (no VSH), to drones produced by an HL (high x low) queen. Because each of the 26 queens was mated to one drone, the resulting colonies were expected to represent the complete range of variability (0 to 100% of the alleles for VSH). To estimate brood removal, we measured mite populations in capped worker brood that was 0 - 3 days postcapping and again 7 days later when the cohort was aged 7 - 10 days postcapping. We correlated removal of mite-infested brood with the relative presence (at 7 - 10 days postcapping) of three classes of foundress mites: (1) viable: those with at least one daughter that could mature before emergence of the host bee; (2) nonviable: those with progeny but with no daughters that could reach maturity; and (3) no eggs: those with dead or nonovipositing foundress mites. As the rate of removal increased, both classes 1 and 2 showed significant declines, whereas class 3 was unchanged. Therefore, oviposition of the mite or something associated with mite oviposition provides the stimulus for bees with the VSH trait to remove mite infested pupae.
This study compared brood production, honey consumption (in winter only), population growth of honey bees (Apis mellifera), and population growth of parasitic mites (Varroa destructor) in hives with open screen or wood as floor material. Two experiments were conducted in Baton Rouge, Louisiana, USA, one in winter (19 colonies) and one in summer (22 colonies). In both experiments, we established uniform colonies of honey bees by subdividing 30 kg of mite-infested bees. Each colony began with about 11 000 bees, no brood, and uniform populations of mites (127 and 480 mites per colony in winter and summer, respectively). The summer test included a third treatment (8 colonies) where a wooden tray (5 cm deep) closed the space beneath a screen floor. After the first 20 days of the experiments, when no adult bees or mites had yet been produced in any of the colonies, the treatments showed no differences in brood production, honey consumption, or survival of adult bees. At nine weeks, colonies with screen floors had fewer mites, a lower percentage of their mite population residing in brood cells (open screen only), and more cells of capped brood. These results suggest that colonies with open-screen floors may hold back the growth of mite populations by decreasing the rate at which mites invade brood cells.
The whole lipid fraction of fresh bee-collected pollen was encapsulated in a starch polymer and added to a whey-yeast pollen substitute. Honeybee colonies fed pollen substitute supplemented with 2, 4, 6 or 8% (dry weight) of the lipid reared significantly more brood to the sealed stage than did colonies fed the substitute without lipid. Colonies fed 2 or 4% lipid reared as much brood as colonies fed pollen. Addition of the starch-coated pollen lipid to the pollen substitute also improved its consumption, but not in proportion to the improvement in brood production; thus the pollen lipid may have influenced brood production directly as well as by increasing protein intake.
Varroa sensitive hygiene (VSH) is a trait of honey bees, Apis mellifera, that supports resistance to varroa mites, Varroa destructor. Components of VSH were evaluated to identify simple methods for selection of the trait. Varroa mite population growth was measured in colonies with variable levels of VSH in two field trials using 24 and 16 colonies. Mite population growth was significantly lower in VSH and hybrid colonies than in control (i.e., unselected) colonies. In resident brood with mite infestations below 5%, the percentage of uncapped pupal cells did not differ significantly among VSH, hybrid and control colonies, but the percentage of recapped cells was highest in VSH colonies (P = 0.03). When brood from more highly infested colonies (9-49% of pupae infested) was introduced for 40 h, VSH colonies reduced infestation more than control colonies (P < 0.01) but final mite fertility was similar (P = 0.12). When infested brood was exposed in colonies for one week, VSH colonies reduced both mite fertility (P = 0.05) and mite infestation (P = 0.02). When highly infested brood was exposed to a subset of colonies for 2 h, control colonies uncapped no or few cells while uncapping in VSH colonies was variable but on average was much higher. Mite population growth in individual colonies was negatively correlated with reduced infestation after 40-h of brood exposure and with reduced mite fertility after one week. The simpler and shorter-term measures (relative to measuring mite population growth) of uncapping, recapping, and reductions in infestation and mite fertility may facilitate selection of VSH by more bee breeders.
Select colony-associated fungi (bee isolates), Absidia sp., Ascosphaera apis, Aspergillus flavus, Fusarium sp., Penicillium glabrum, Mucor sp., showed a 40% reduction in radial growth rate with formic acid, a 28% reduction with oxalic acid, and a 15% reduction with fructose and high fructose corn syrup (HFCS) when grown on supplemented media at 30°C to mimic colony conditions. No effect, suppressing or promoting growth, was observed on other colony-associated fungi, Alternaria sp., Aspergillus niger, Cladosporium cladosporioides, Rhizopus sp. and Trichoderma sp., except 0.1M formic and oxalic acid. Sensitivity to these compounds did not correlate with the fungus species being a slow- or fast-grower and sensitivity to one compound did not translate to sensitivity to another compound. Given the competitive nature and high-sporing (conidia) activity of these species, our results suggest that alteration or disruption of the colony mycoflora can occur by use of these compounds. This may indicate a possible link between compound application and incidence of bee fungal pathogens.
A method is described for measuring rate of protein synthesis in vitro by hypopharyngeal glands of honeybees. No direct correlation was apparent between rate of synthesis and size of the acini of the glands. Full-grown glands of summer bees showed highly variable synthetic activity. Glands of known nurse bees demonstrated the highest rates of protein synthesis. Winter bees with completely filled acini showed reduced activity, but protein synthesis increased in spring when brood rearing started.
(Z)-ll-eicosen-l-ol, a recently discovered volatile component of the sting apparatus, is attractive to foragers trained to collect sugar syrup and to scout bees, but does not enhance the attractiveness of the Nasonov pheromone.
We analyzed the effect of mercury (Hg) on the hepato-nephrocitic system (HNS) of Bombus atratus workers exposed to an estimated concentration similar to that found in honey stores of neotropical bees (110 ppb). The bees were divided into control and experimental groups. A solid mixture of honey, pollen and organic soy was offered to both experimental groups, ad libitum. The control group received distilled water and the exposed group received a 110 µg.L⁻¹ (110 ppb) Hg solution. After 48 h of exposure, the bees were cryo-anesthetized, and the dorsal vessel was dissected directly in 4% paraformaldehyde. The samples were prepared for routine morphological analysis (HE), fluorescent histochemical staining (Acridine Orange and F-actin + DAPI), and in situ immunohistochemical labeling (Hsp70 and Hsp90). Our results showed that both the trophocytes and oenocytes of bees exposed to mercury exhibited chromatin damages. The Hg exposure also induced trophocytes deactivation of the nucleus-cytoplasm exchange as a result of branched contour loss of the nuclei. The pericardial cells were predominantly found at stage IV with pyknotic nuclei. Although the fluorescence intensity of both Hsp70 and Hsp90 was reduced in the exposed group compared to the control group, there was an indication of misfolded proteins. In conclusion, our results showed that the concentration of 110 µg.L⁻¹Hg, which can be found in the honey stores of B. atratus colonies, has severely damaged the HNS of B. atratus workers. These effects can trigger major damage to their populations, contributing to bee declines in natural environments worldwide.
Values of the ratio 13C to 12C are given for 84 representative honeys from the United States and 35 honeys imported into the United States. Remarkably uniform results were obtained; the average δ13C for all samples was—25·4%, and the coefficient of variation only 3·86%.The values are those expected from plants with the C3 (Calvin) photosynthetic pathway. They provide the basis for the detection of corn-derived syrups in honey.
Honey bee pollen is a good source of nourishing substances with a wide range of potential therapeutic properties. The aim of the present study was to evaluate the composition and antioxidant activities of bee pollens collected from commercial hives in Poland. Plant sources were buckwheat and rapeseed. The pollen loads differed in color, so samples were separated into color fractions. The highest content of minerals (K, Ca, P) was in samples from: buckwheat (S1) and rapeseed (S7). The rapeseed pollen had significantly higher amounts of polyphenols and flavonoids, and higher values of antioxidant capacities as measured by DPPH, FRAP and ORAC assays. 13C CPMAS NMR spectra revealed the presence of carbohydrates (including polymers), lipids, polyphenols and amino acids. Solid-state 1H MAS spectra showed the resonances of lipids, sugars and different amounts of water. Our results indicate that 1H and 13C MAS NMR spectroscopy can be very useful to characterize bee pollen types.
The study was carried out in order to characterize honeys produced in the Yucatan peninsula by analysis of the delta C-13 isotope and to detect whether adulterants were present. A total of 234 honey samples, the harvesting of which coincided with the main flowering season of tajonal (Viguiera dentata) and tzitzilche (Gymnopodium floribundum), were collected from the Mexican states of Yucatan, Campeche and Quintana Roo. Two types of samples were taken: honeycomb honey (for characterization) and honey obtained from the main honey processing plants (to detect possible adulterations). The analyses were performed using stable carbon isotope ratio analysis. The isotopic values of pure honeys extracted from combs at the laboratory were: -26.3 +/- 0.32 delta parts per thousand (n = 28) for tajonal and -24.5 +/- 0.30 delta parts per thousand (n = 33) for tzitzilche. Adulterations were not detected in tajonal honeys; however, the tzitzilche honeys had 25.3% samples within the range of suspected adulteration and 5.7% within the range of adulterated.
The water-soluble antioxidant capacity of 19 samples of honey from 14 different floral sources was determined by a spectrophotometric assay. The highest concentration of antioxidants measured was 20.3 times that of the lowest, showing that great variation exists in the chemical nature of honey from different floral sources. Antioxidant content was positively correlated with both water content and honey colour. Because of the health benefits of dietary antioxidants, floral source should be a factor in evaluating the potential of honey as an antioxidant-containing food supplement.
Map showing relative risk of overwinter loss at regional level (where sufficient beekeepers were represented in a region, taken as 6 or more beekeepers here).
In this short note we present comparable loss rates of honey bee colonies during winter 2015/16 from 29 countries, obtained with the COLOSS questionnaire. Altogether, we received valid answers from 19,952 beekeepers. These beekeepers collectively wintered 421,238 colonies, and reported 18,587 colonies with unsolvable queen problems and 32,048 dead colonies after winter. This gives an overall loss rate of 12.0% (95% confidence interval 11.8–12.2%) during winter 2015/16, with marked differences among countries. Beekeepers in the present study assessed 7.6% (95% CI 7.4–7.8%) of their colonies as dead or empty, and 4.4% (95% CI 4.3–4.5%) as having unsolvable queen problems after winter. The overall analysis showed that small operations suffered higher losses than larger ones. A table with detailed results and a map showing response and relative risks at regional level are presented.
In this research, for the first time, 16 polycyclic aromatic hydrocarbons (PAHs) in 33 types of honey samples have been analyzed using an efficient, sensitive and rapid high-density solvent-microextraction (HDS-ME) technique coupled to gas chromatography-mass spectrometry (GC-MS). Important parameters in the extraction process were optimized using central composite design (CCD). Good linear relationships were chosen for 16 PAHs in the range of 1–200 ng g⁻¹, with a correlation coefficient (R²) higher than 0.94. The limits of detection and limits of quantification were 0.3–0.8 ng g⁻¹ and 0.9–2.4 ng g⁻¹, respectively. The relative standard deviations for six similar analyses at the optimized point were less than 9%. The recoveries of the proposed method were obtained between 86% and 102%. High recovery, low consumption of the solvent, speed, ease of use and good elimination of matrix interference compared to other methods are the advantages of the proposed method. The performance of the present work was confirmed by the standard addition method and satisfactory results were obtained. The concentrations of PAHs in honey samples were found lower than 11 ng g⁻¹.
The diet of several European bee-eater Merops apiaster colonies was studied in the Murcia Region (SE Spain) during the spring and summer of 2009, in order to assess their predation on the honey bee Apis mellifera. The examination of invertebrate remains found in pellets revealed the dominance of Hymenoptera and Coleoptera in the average diet, and a similar consumption of honey bees compared to other species of Hymenoptera. The number of honey bees and other Hymenoptera recorded in the pellets varied both spatially (between locations) and temporally (along the main reproductive phases). On average, it was estimated that a single bee-eater consumed 1333.39 ± 759.8 honey bees during its complete stay in the region, far below the theoretical regeneration capacity of a single honey bee colony (36,000–45,000 honey bees per month from April to July). Consequently, under normal circumstances the effect of bee-eater predation on local apiaries appears negligible, and partially dependent on the availability of alternative prey.
The number of apiaries and bee hives infected with Nosema in the districts of Hatay region (NP; Nosema positive).
Visual of 218-219 PCR product (bp) particular to N. ceranae in the agarose gel (M; Marker 100 bp, 1-5; Honey bee samples positive for N. ceranae, 6; N. ceranae and N. apis positive control (mix), 7; N. apis positive control, 8; Negative control (distilled water)).
The aim of this study is to determine the prevalence of nosemosis by using microscopic and molecular (Polymerase Chain Reaction (PCR)) methods in honey bees of Hatay province, and to investigate the effects of beekeepers' attitudes and behaviors and apiary conditions on the spread of disease through a survey study. In the study, adult bee samples were collected from 450 hives in 75 apiaries in 6 districts of the Hatay region between March 2019 and May 2019. This particular area was chosen because many beekeepers overwinter their hives here and movement of colonies in and out of the region is common. As a result, it was determined that there was Nosema ceranae infection in 45% of the apiaries; overall, 20% of the total hives were infected in Hatay province. However, Nosema apis was not detected. In the statistical evaluation of the survey study that determines the effects of apiary conditions and beekeepers' attitudes and behaviors on the spread of the disease, the infection rate in Caucasian (Hybrid) bee race (53.7%) was found to be significantly higher than that of the native (Hatay) bee race (23.8%) (p < 0.05). In addition, the rate of disease (50.0%) in apiaries that use the same beekeeping equipment like frames, bee brush and frame scraper among different hives was found to be significantly higher than those that do not use the same equipment among different hives (18.2%) (p < 0.05).
Temporal polyethism is based on physiological differences related to the honey bee activities into the colony, suggesting a different requirement of antioxidant activity in each honey bee development stage. The superoxide dismutase (SOD), the catalase and the glutathione S transferase (GST) activities were investigated in ventriculus, thorax and wings of pupae with dark brown eyes newly emerged, nurse, guardian and forager bees. SOD activity resulted significantly higher in ventriculus of newly emerged bees than the others investigated development stages, while in the thorax, newly emerged and guardian bees reported significantly higher SOD activity than pupae in dark brown eyes stage, nurses and forager bees. No, statistically differences in catalase activity resulted among honey bee ages. In pupae, nurse, guardian, and forager bees, GST activity resulted higher in the wings than in the other honey bee organs. Further investigations are desirable to clarify the distribution of the antioxidant enzymes in the different organs of the honey bee.
The laboratory LD50 values of organophosphate, carbamate, organochlorine including cyclodienes and pyrethroid insecticides were determined for workers of Trigona spinipes (F., 1793). Determinations used topical application techniques from which dose-mortality was derived using Bliss’ method (1935). In order of decreasing toxicity the LD50 values for workers, in ug bee were as follows: heptachlor, 0.0168; dieldrin, 0.0289; Cypermethrin, 0.0704; permethrin, 0.0724; parathion, 0.0956; lindane, 0.1331; methomyl, 0.1402; dicrotophos, 0.1685; endosulfan, 0.2097; malathion, 0.2649; acephate, 0.4234; carbaryl, 0.7472; fenvalerate, 1.0880. The insecticides tested were highly toxic to T. spimpes.
Top-cited authors
Ernesto Guzman
  • University of Guelph
Jay Evans
  • United States Department of Agriculture
Jozef Van der Steen
  • Alveus AB Consultancy
Maria Bouga
  • Agricultural University of Athens
Keith S Delaplane
  • University of Georgia