Hygienic behaviour in the honeybee (Apis mellifera) has been shown to be an effective control mechanism against brood diseases such as chalkbrood and AFB. Chalkbrood has proven to be problematic for the Australian honey industry since it was identified here in 1993. Hygienic behaviour is a much studied trait. Rothenbuhler investigated the genetic basis of hygienic behaviour, proposing a two-gene model to explain the uncapping and removal of dead brood. His elegant experiment remains the textbook example of a behavioural genetic study. Although this model has been challenged, it is still generally agreed that a small number of unlinked genes produce a large effect on hygienic behaviour, that hygienic alleles are recessive and are inherited in a Mendelian manner. Experimental backcross colonies were produced from an inbred hygienic line and an inbred non-hygienic line, both provided by Dr. Marla Spivak, University of Minnesota. These backcross colonies were assessed for hygienic behaviour using a standard assay. Statistical analyses of the field data indicated that the genetic basis of the trait was more complex than either the simple Mendelian and widely accepted two-gene or three-gene models that have been proposed previously. Molecular techniques, linkage mapping and QTL analysis then were employed to determine how many loci directly influence hygienic behaviour and the relative level of influence and location of each locus within the genome of A. mellifera. Full multipoint linkage analysis by Mapmaker v3.0 software produced a new genetic map of the honeybee comprised of 358 marker loci ordered over 25 linkage groups spanning a total distance of 3406.2 cM. The average distance between each marker was 9.5 cM. QTL analysis of the experimental data identified seven putative genetic markers associated with hygienic behaviour. QTLs located on linkage groups 2, 4, 6 and 22 were detected for both overall hygienic behaviour and uncapping behaviour only. Individually, each QTL is of relatively small effect with each explaining only 9% � 15% of the variance in hygienic levels observed. Collectively, the putative QTLs identified here explain 79.4% of the observed variance in the expression of hygienic behaviour. These results indicate that there are many genes of low to moderate effect rather than few genes of large effect involved in this complex behavioural trait. This is typical of inherited quantitative traits which do not exhibit Mendelian phenotypic ratios. DNA extracted from the brood samples taken during testing of commercial stock, and from individual bees identified as either highly hygienic or non-hygienic in a reciprocal backcross experiment, were screened with the candidate markers associated with putative QTLs to test their diagnostic power. Unfortunately, none have produced reliably diagnostic DNA profiles. As we have now shown that hygienic behaviour is a polygenic, quantitative trait, simple diagnostic markers for Rothenbuhler's 'uncapping' and 'removal' genes are unlikely to be achieved. Our results show that the most likely way to improve disease resistance in Australian stock is via traditional methods of recurrent selection. The project was responsible for the importation of new genetic material into Australia from the United States. This hygienic stock has been well received by industry, has been widely disseminated, and incorporated into local breeding programs. We hope that it has lead to a general improvement in the level of disease resistance in Australian commercial bees.

Hygienic behaviour in the honeybee (Apis mellifera) has been shown to be an effective control mechanism against brood diseases such as chalkbrood and AFB. Chalkbrood has proven to be problematic for the Australian honey industry since it was identified here in 1993. Hygienic behaviour is a much studied trait. Rothenbuhler investigated the genetic basis of hygienic behaviour, proposing a two-gene model to explain the uncapping and removal of dead brood. His elegant experiment remains the textbook example of a behavioural genetic study. Although this model has been challenged, it is still generally agreed that a small number of unlinked genes produce a large effect on hygienic behaviour, that hygienic alleles are recessive and are inherited in a Mendelian manner. Experimental backcross colonies were produced from an inbred hygienic line and an inbred non-hygienic line, both provided by Dr. Marla Spivak, University of Minnesota. These backcross colonies were assessed for hygienic behaviour using a standard assay. Statistical analyses of the field data indicated that the genetic basis of the trait was more complex than either the simple Mendelian and widely accepted two-gene or three-gene models that have been proposed previously. Molecular techniques, linkage mapping and QTL analysis then were employed to determine how many loci directly influence hygienic behaviour and the relative level of influence and location of each locus within the genome of A. mellifera. Full multipoint linkage analysis by Mapmaker v3.0 software produced a new genetic map of the honeybee comprised of 358 marker loci ordered over 25 linkage groups spanning a total distance of 3406.2 cM. The average distance between each marker was 9.5 cM. QTL analysis of the experimental data identified seven putative genetic markers associated with hygienic behaviour. QTLs located on linkage groups 2, 4, 6 and 22 were detected for both overall hygienic behaviour and uncapping behaviour only. Individually, each QTL is of relatively small effect with each explaining only 9% � 15% of the variance in hygienic levels observed. Collectively, the putative QTLs identified here explain 79.4% of the observed variance in the expression of hygienic behaviour. These results indicate that there are many genes of low to moderate effect rather than few genes of large effect involved in this complex behavioural trait. This is typical of inherited quantitative traits which do not exhibit Mendelian phenotypic ratios. DNA extracted from the brood samples taken during testing of commercial stock, and from individual bees identified as either highly hygienic or non-hygienic in a reciprocal backcross experiment, were screened with the candidate markers associated with putative QTLs to test their diagnostic power. Unfortunately, none have produced reliably diagnostic DNA profiles. As we have now shown that hygienic behaviour is a polygenic, quantitative trait, simple diagnostic markers for Rothenbuhler's 'uncapping' and 'removal' genes are unlikely to be achieved. Our results show that the most likely way to improve disease resistance in Australian stock is via traditional methods of recurrent selection. The project was responsible for the importation of new genetic material into Australia from the United States. This hygienic stock has been well received by industry, has been widely disseminated, and incorporated into local breeding programs. We hope that it has lead to a general improvement in the level of disease resistance in Australian commercial bees.

The discovery of the honeybee-specific ectoparasitic mite Varroa destructor in South Africa in October 1997 raised the spectre of massive honeybee colony losses as has occurred in most parts of the world where the varroa mite has been found. This was particularly concerning in Africa because of the importance of honeybees in the pollination of indigenous and commercial crops, and because of the numbers of small-scale beekeepers in Africa. The mite has now spread throughout South Africa and is found in almost all honeybee populations, both commercial and wild, and is also now present in most neighbouring countries. Varroa has not left a trail of destruction in South Africa as had been expected and no large scale collapse of the honeybee population occurred, despite the majority of beekeepers deciding not to protect their hives with chemical varroacides. Some colony losses did occur at the front of the varroa spread, and all colonies were found to be deleteriously affected by the mite which developed populations of 50 000 and more in some colonies. Infected colonies were also not as efficient as pollinators as uninfected colonies. Colonies exhibited all the same varroa effects witnessed in other parts of the world, with the exception that the majority of colonies did not die as a result of the infestation. The relative tolerance of African bees to the varroa mite has been confirmed by the long-term monitoring of both wild honeybee populations and commercial stock, and by population dynamic studies of the mites. In both wild and managed honeybee populations varroa appears to have been reduced to the status of an incidental pest. The development of mite tolerance took 3-5 years in the Cape honeybee (Apis mellifera capensis) and 6-7 years in the Savanna honeybee (Apis mellifera scutellata). The rapid development of mite tolerance in the Cape bee is thought to be due to the well developed removal of varroa-infested brood and the short post-capping period of worker brood. Together these resulted in a very rapid increase in infertile mites in the colony, the collapse of the mite population, and varroa tolerance. Tolerance does not develop as rapidly in Savanna honeybees as the post-capping period in these bees is similar to that of European bees and does not result in as many infertile mites. Nonetheless, varroa tolerance in Savanna bees develops more rapidly than would be the case in European bees because of more effective hygienic removal of varroa-infested brood. In both Cape and Savanna bees, the absence of varroacide applications and a “live-and-let-die” approach to the wild and commercial honeybee populations was crucial to the developed of population-wide varroa tolerance, in contrast to the selective breeding and pesticide treadmill practised in most parts of the world in an effort to get rid of the varroa mite. Varroa destructor is concluded not to be a serious threat to honeybees and beekeeping in Africa, and efforts should be made to prevent the use of pesticides and techniques that could hinder the development of natural mite tolerance in Africa. / Dissertation (MSc (Entomology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted

Pollination is an essential ecosystem service, increasing reproductive success of many crops, which can be provided by managed pollinators, wild bees (including honeybees) and other insect pollinators. However, the pollination services and the economic value of wild pollinators are often underestimated. Better understanding of the factors that influence honeybee foraging behaviour and pollination efficiency can contribute to the improvement of management practices that aim to enhance crop pollination and ecosystem services. The objectives of this study were to investigate the importance of managed honeybees and wild honeybees to sunflower pollination as well as to evaluate the response of honeybees to different levels of floral rewards and to behavioural interactions with wild flower visitors. The study was conducted in 16 commercial sunflower farms and one experimental farm of South Africa during the 2009 sunflower flowering season. The results showed that insects, particularly honeybees, were efficient pollinators, improving sunflower production in all self-fertile sunflower cultivars used in this study. Furthermore, wild honeybee colonies were found to be as efficient as managed honeybee colonies in sunflower pollination near to natural habitat. Both sunflower yield and the abundance of pollinators decreased with distance from natural habitat, suggesting that sunflower yield is directly correlated with the abundance of pollinators. The amount of nectar present in the florets of sunflower significantly affected pollinator behaviour, influencing honeybee visitation length and foraging rate which prefer to exploit floral rewards from the same source if they find the higher amount per foraging trip, possibly having a negative impact on cross-pollination. Moreover, the concentration of nectar collected from honeybees was significantly lower than the nectar concentration from florets, suggesting that honeybees diluted highly concentrated sunflower nectar with their saliva to their optimum concentration level. Interspecific exploitative competition between honeybees and wild pollinators (wild bees, butterflies and moths) significantly increased the movement of honeybees among sunflower heads, which enhances cross-pollination. Furthermore, behavioural interactions influenced the length of foraging time spent by individual honeybees per sunflower head. Butterflies were the most influential in enhancing honeybee foraging movement, followed by wild bees and then moths. The importance of a given flower visitor species to honeybee movement is likely related to the size of the visitor, as the bigger size of butterflies and movement of their wings increases the chance of disturbing a neighbouring honeybee. Conservation of natural habitat is important to maintain the diversity of flower visitors which indirectly contribute to crop production by enhancing honeybee foraging activity and consequent direct pollination service. Furthermore, the pollination effectiveness of wild pollinators, density of wild honeybees surrounding sunflower fields and effects of human activities on pollination disruption are suggested as topics for future research. / Dissertation (MScAgric)--University of Pretoria, 2010. / Zoology and Entomology / unrestricted

Thesis (MScConsEcol)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Apis mellifera, the honeybee, is regarded as the most crucial insect pollinator to South African agriculture as it is the only managed pollinator used in the pollination of commercial agricultural crops. Essential to sustaining managed honeybees is the supply of adequate and sustainable forage resources upon which managed honeybee colonies can forage throughout the year. In most instances agricultural pollination services are only required for a brief period of the year, and consequently managed honeybee colonies need to be sustained on a variety of alternate forage resources for the remaining months of the year. As an essential resource in maintaining managed honeybee colonies, honeybee forage can subsequently be linked to the maintenance of agricultural crop pollination. Exotic honeybee forage species have always been an important part of managed honeybee foraging patterns, however recent pressure to control exotic plant species in South Africa has put this type of honeybee forage under threat. This studies’ first aim was focused on identifying the historic honeybee forage use pattern in South Africa, thereby identifying which forage species have maintained managed beekeeping up until this point. A comprehensive literature review of the South African Bee Journal, dating back to the journals first publication in the 1910’s documented both the exotic and indigenous forage species that have sustained the beekeeper industry in the past. Significance ratings of individual species were determined according to the number of times a species was cited in the literature throughout the review period. Although indigenous species where cited in the literature, the predominately used forage species was found to be exotic, highlighting the role these species played in the development of South African beekeeping. Secondly, this study identifies and highlights the current honeybee forage usage pattern in South Africa. By means of a country wide honeybee forage questionnaire, honeybee forage usage patterns were determined based on forage species usage by beekeepers in different provincial regions. Important forage species were highlighted in each region on the basis of number of colonies using individual forage species. In addition to identifying current forage usage, this questionnaire was able to help estimate the number of managed honeybee colonies in South Africa at present, given that census data is not yet available. Even though there is currently a greater awareness and usage of indigenous forage species, it remains that the predominantly used forage source are exotic forage species. Whilst there appears to be a movement and awareness towards the use of indigenous forage species across South Africa, forage species usage patterns have not shift dramatically in the last century. In order to fulfill their foraging requirements, managed honeybee colonies remain heavily dependent on exotic species, especially that of Eucalyptus and certain agricultural crop species. The removal of Eucalyptus should thus just be done in sensitive environments, while all woodlots should be demarcated and managed to ensure continued forage availability. In turn growers of forage crops should be made aware of their contribution to provincial honeybee forage resources. / AFRIKAANSE OPSOMMING: Apis mellifera, die heuningby, word beskou as die belangrikste insek bestuiwer vir kommersiële boerdery in Suid Afrika, aangesien dit die enigste bestuurde bestuiwer is wat vir kommersiële landbou-gewasse gebruik word. Die beskikbaarheid van voldoende en volhoubare voedselbronne vir bestuurde heuningby kolonies is noodsaaklik vir hul voortbestaan. Bestuiwing deur hierdie insekte is in die meeste gevalle net nodig vir ʼn kort tydperk elke jaar, dus benodig bestuurde heuningby kolonies ʼn verskeidenheid van alternatiewe voedselbronne vir die oorblywende maande. Heuningby voedselbronne is noodsaaklik vir die handhawing van heuningby kolonies, en dus kan die beskikbaarheid van hierdie bronne gekoppel word aan die onderhouding van landbougewas bestuiwing. Uitheemse heuningby voedsel spesies is belangrik vir die voortbestaan van die heuningby, maar ’n toename in uitheemse plant spesies bestuur bedreig hierdie heuningby voedselbronne. Die eerste doel van hierdie studie was om die historiese heuningby voer gebruik patrone in Suid Afrika te identifiseer, om vas te stel watter plant spesies tot nou toe belangrik was vir byboerdery. ʼn Omvattende literatuuroorsig van die South African Bee Journal, vanaf die eerste publikasie in die 1910’s, het bevestig watter inheemse en uitheemse spesies belangrik was vir die voortbestaan van byboerdery in die verlede. Betekenis gradering van individuele spesies was bepaal volgens die aantal kere wat ʼn spesies aangehaal is in die literatuur binne die oorsigtydperk. Alhoewel inheemse plant spesies aangehaal was in die literatuur, was die meerderheid van die spesies uitheems. Dit dui dus die belangrikheid van uitheemse spesies aan vir die ontwikkeling en voortbestaan van Suid Afrikaanse byboerdery. Die tweede doel van hierdie studie was om die huidige kos soek patrone van die heuningby in Suid Afrika aan te wys. Die heuningby voer gebruik patrone is bepaal deur ʼn landwye vraelys, wat die voedselbron spesies van byeboere in die verskillende provinsies ondersoek het. Belangrike voedselbron spesies in elke streek was uitgelig in terme van die aantal by kolonies wat daardie spesie gebruik. Hierdie vraelys was ook gebruik om vas te stel hoeveel bestuurde heuningby kolonies daar tans in Suid Afrika is, aangesien sensus data nog nie beskikbaar is nie. Alhoewel daar tans ʼn groter bewustheid is van die gebruik van inheemse spesies as ʼn voedselbron, word uitheemse spesies steeds die meeste gebruik. In die laaste eeu was daar nie ʼn dramatiese verskuiwing vanaf uitheemse na inheemse spesies nie, ten spyte van die toeneemde bewustheid. Ten einde hul voedsel vereistes te voldoen, bly bestuurde heuningby kolonies afhanklik van uitheemse spesies, veral Eucalyptus spesies en sekere landbou-gewasse. Eucalyptus moet net in sensitiewe omgewings verwyder word, en bebosde gebiede moet afgebaken en bestuur word om te verseker dat hul as volhoubare voedselbronne beskikbaar bly. Verder moet produsente van gewasse wat byeboere kan gebruik bewus gemaak word van hul bydrae tot die voedselbronne van bestuurde heuningbye in hul streek.

The dissertation on the influence of temperature and humidity of the environment on the reproduction of the honey bee (Apis mellifera) describes the effect of the observed physical quantities on the entire bee during the growing season. Three habitats were monitored under different conditions. The measuring devices were always located inside and outside one colony of each habitat. In cooperation with colleagues from the Faculty of Electrical Engineering, ČVUT in Prague, the physical parameters monitoring was extended by monitoring the sound and weight of the hives - hive assemblies at the site located at the Agricultural Faculty of the University of South Bohemia. The data collection system in beehives was designed as a fully autonomous modular system. Measured data was processed and evaluated by statistical programs. The results showed that the hives observed differ in the number of bee queens found in the growing season and also in the number of frames found. Near-fetal temperatures were measured for correct development of the bee (32 °C to 36 °C). Colonies in the observed periods of 2014, 2015 and 2016 had to actively increase the relative humidity inside the hive in spring and summer. The colony reacts to changes in air temperature by varying intensity of sound. The results revealed the differences between the intensity of bee sounds in different temperature conditions. The highest sound intensity was detected at temperatures below 10 ° C (36.71 W.m-2), the lowest being at temperatures above 29.4 °C (26.25 W.m-2). The correlation coefficients were very low (r = 0.180) to medium (r = 0.463) and the correlation coefficient (r = 0.555) changed with a change in the temperature group. In order to evaluate the optimal conditions for honeybee rearing, the temperature and humidity monitoring can be used. The most suitable temperatures were in the range (29.5-34.3 °C) and temperatures above 34.4 °C. In terms of humidity, the temperature range (20-29.4 °C) and (29.5-34.3 °C) are the most appropriate. Changes in the observed values also affect the queen's bee in the colony. The data obtained from the long-term monitoring of these variables can help us to construct a THI index for bees, which would be a suitable tool to evaluate the optimal conditions for bees.

We analyzed a total of 760 worker bees, two samples per colony, 390 colonies in 26 provinces in Turkey to determine and compare the genetic variation of Turkish honey bee (Apis mellifera L.) populations using 10 primers for RAPD and 6 microsatellite loci. Mean gene diversity levels ranged from 0.035 (Sanliurfa) to 0.175 (Antalya) for RAPD and 0.449 (Mugla) to 0.739 (Artvin) for microsatellite markers. Private band patterns and alleles, pairwise FST values support that the Anatolian honey bees belong to C lineage except for Hatay and Sanliurfa populations illustrated from previous findings of mitochondrial DNA studies. Genetic differentiation (GST) from RAPD data ranged from 0.060 (Bilecik and Mugla) to 0.395 (G&ouml / k&ccedil / eada and Sanliurfa). The genetic diversity (FST) for microsatellites ranged from -0.068 (G&ouml / k&ccedil / eada and &amp / #272 / zmir) to 0.347 (Konya and Mugla). The results of the present research are in agreement to that of previous study in Turkish honey bee populations which used different microsatellite loci. That is the genetic variation was the highest in African, the lowest in European and intermediate in the Mediterranean honey bee populations. The data presented here indicate that in spite of extensive migratory beekeeping, there is still a large genetic differentiation among honey bee populations. These results should be considered in establishment of conservation plans particularly in moving of colonies between regions. The most importantly introduction of bees with foreign origin and distribution queen bees from one center to all over the country which will homogenize the gene pool of the populations should be prevented

We analyzed the genetic structures of 11 honeybee (Apis mellifera) populations from T&uuml / rkiye and one population from Cyprus using 9 microsatellite loci. Average gene diversity levels were found to change between 0,542 and 0,681. Heterozygosity levels, mean number of alleles per population, presence of diagnostic alleles and pairwise FST values confirmed the mitochondrial DNA finding that Anatolian honeybees belong to north Mediterranean (C) lineage. We detected a very high level of genetic divergence among populations of T&uuml / rkiye and Cyprus based on pairwise FST levels (between 0,0 and 0,2). Out of 66 population pairs 52 were found to be genetically different significantly. This level of significant differentiation has not been reported yet in any other study conducted on European and African honeybee populations. High allelic ranges, and high divergence indicate that Anatolia is a genetic centre for C lineage honeybees. We suggest that certain precautions should be taken to limit or forbid introduction and trade of Italian and Carniolan honeybees to T&uuml / rkiye and Cyprus in order to preserve genetic resources formed in these territories in thousands of years. Effectivity at previously isolated regions in Artvin, Ardahan and Kirklareli was confirmed by the high genetic differentiation in honeybees of these regions. Genetically differentiated Karaburun and Cyprus honeybees v and geographical positions of the regions make these zones first candidates as new isolation areas.

The initial phase in the development of a biological control strategy is screening of biological control agents. Secondary to this phase is the establishment of accurate, effective application techniques. However, successful control requires a thorough understanding of all factors affecting the relationship between host plant, pathogen and other microbes. The purpose of this study was to screen and identify potential bacterial antagonists against Alternaria, a fungal citrus pathogen, attachment of the antagonists to bees, and bee dissemination of the antagonist to citrus flowers. A total of 568 bacterial epiphytes were screened on agar plates for antagonism against Alternaria. Only eight of these isolates, which were identified as Bacillus subtilis, B licheniformis, B. melcerons, B. polymyxa, B. thermoglycodasius, B. sphaericus, B. amiloliquefaciens, and B. coagulans, showed inhibitory effects on the growth of Alternaria. The most effective isolates were B. subtilis and B. licheniformis. Further screening was done with B. subtilis and B. subtilis commercial powder (Avogreen). These bacteria were sprayed on citrus flowers for colonisation studies. Mean populations of B. subtilis and the commercial powder recovered from the flowers were 104 and 103 cfu/stamen respectively. The organisms colonised the styler end and ovary of the flowers when observed under scanning electron microscope (SEM). Avogreen was placed in an inoculum dispenser, which was attached to the entrance of the hive. Honeybees emerging from the beehive acquired 104 cfu/bee. The powder attached to the thorax and thoracic appendages, as revealed by SEM. One active beehive was placed in an enclosure with fifteen flowering citrus nursery trees in pots for dissemination trials. Mean populations of commercial B. subtilis recovered from the flowers visited by bees were 104 cfu/stamen. Electron microscope studies revealed that the antagonist was colonising the styler end and ovary of the flowers. Field dissemination studies were unsuccessful due to low yields. / Dissertation (Magister Institutiones Agrariae)--University of Pretoria, 2003. / Plant Production and Soil Science / unrestricted

One of the benefits of colonial living in insect societies is the ability to build a nest which enables the maintenance of a homeostatic microenvironment. The detrimental and uncertain effects of fluctuating ambient conditions are thus avoided. An extensive amount of work has documented the regulation of respiratory gases and temperature by honeybee (Apis mellifera) colonies but relatively little is known of their water relations. Nest humidity influences the fitness of the honeybee colony by affecting adult and brood mortality, microbial and parasitic growth, nectar concentration and thermoregulation. This study aims at determining whether honeybee colonies are able to actively regulate humidity within their nest or whether humidity is stabilised merely as consequence of other socially regulated parameters. As a first step in understanding water relations in a hive, the daily, seasonal and two-dimensional humidity patterns are described in diverse contexts: various subspecies, nest architectures, ambient climates and colony conditions. The humidity in the brood nest of a healthy honeybee colony does not show a daily pattern: mean hourly RH remains between 50 and 60 % and high vapour pressure deficit results in a large evaporative capacity. Two-dimensional humidity patterns show that a vapour pressure gradient exists from the central brood area to the periphery of a hive. This finding suggests possible active regulation by workers and to test this idea we determined the behavioural response of a group of workers to a humidity gradient. Young honeybee workers in the absence of brood exhibit a weak hygropreference for approximately 75% RH. When brood is present the expression of this preference is further weakened, suggesting that workers tend to the brood by distributing evenly in the gradient. In addition, fanning behaviour is shown to be triggered by increasing humidity adding to our understanding of this behaviour. Although these results suggest that humidity in honeybee colonies is actively controlled by workers, passive mechanisms are also involved in the observed patterns. Cocoons that are spun by the larvae accumulate in cells and these hygroscopic cocoons contribute to passive stabilisation of humidity. Old comb containing cocoons absorb 11 % of its own mass in water when placed in high humidity and this water can readily evaporate into the atmosphere when humidity decreases. This buffering effect may increase brood survivorship by maintaining a high and stable humidity in the brood cells. This study contributes to our understanding of the complex mechanisms that govern microclimatic regulation in social insect nests and specifically the active and passive mechanisms that ensure homeostasis of honeybee nest humidity. Copyright / Dissertation (MSc)--University of Pretoria, 2008. / Zoology and Entomology / unrestricted