Insects are considered to be responsible for 80-85% of all pollination, with honeybees being well known for their pollination services for many crops. The effect of managed honeybee pollination on sunflower seed yield and quality (germination percentage and oil content) was investigated at the University of Pretoria experimental farm and in commercial sunflower fields at Settlers. This was done through pollinator exclusion and pollinator surveys on sunflower field plots located at different distances from managed honeybee colonies. Observations on the foraging behaviour and activity of honeybees throughout the day were also made. The data presented in this thesis reveal that seed quantity and quality of sunflower increased significantly as a result of insect visits. Insect pollination improved the mass of 100 seeds (by 38%), as well as their germination percentage (by 38%) and oil content (by 36%). Moreover, visitation frequency, seed yield and quality were negatively correlated with distance to the honeybee hives, suggesting that the distribution of honeybee colonies is not enough to maintain an adequate pollination service throughout the large sunflower fields at Settlers. Honeybee foraging activity varied throughout the day, the highest activity being from 9h00 until 16h00, and activity was correlated with temperature. The results of this study suggest that the use of managed honeybees in sunflower crop production can effectively increase the seed quality and quantity, but additional management measures should be considered to improve production in large monocropping farms that are currently isolated from pollinator sources. Additional provision of honeybee colonies is needed in sunflower production areas during the flowering period. Furthermore, as our results show that in the presence of pollinators other than honeybees seed yield was also improved, management measures that promote the biodiversity of sunflower visitors may also have an important contribution. / Dissertation (MScAgric)--University of Pretoria, 2010. / Zoology and Entomology / unrestricted

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy / In this dissertation the physical and chemical alterations induced by mastication and manipulation of wax by the worker bee in honeycomb construction, and the subsequent contribution afforded the structural integrity of the nest, are elucidated. In comb building, the freshly secreted wax scales are mandibulated together with a frothy salivary emulsion, and added piece-meal to form honeycomb. Textural modifications were revealed using X-ray crystallography. While virgin scale wax is highly structured, with the crystallites aligned approximately perpendicular to the planar surface, comb wax has a random crystallographic arrangement. This reflects a disruption of the crystallite structure following the mechanical insult of mastication. Chemical analyses included investigation of both lipid and proteinaceous elements. Lipid composition was evaluated by enzyme-catalyzed as well as thin-layer and gas-liquid chromatographic methods. The results indicate a reduction in scale diacylglycerols with a corresponding increase in comb saturated monoaeylglycerols. Such modifications are highly suggestive of lipase activity within the salivary addition. The proteins of comb and scale wax were analyzed electrophoretically, under reduced conditions. Each wax possesses unique polypeptide fractions, in addition to sharing common protein species, It is speculated that those in common represent integral proteins, such as transport molecules, while the disparities noted may be due to salivary enzymatic degradation, or even glycosylation. The effects of these textural and chemical alterations on the mechanical behaviour of the waxes was assessed. Tensile tests were performed on a variety of scale and comb wax preparations over the range of temperatures likely to impinge on the honeybee nest. These investigations reveal the specific structural contributions made by each of the physico-chemical alterations described. Further, they demonstrate that while scales are ideal moulding materials due to their high distensibility and low stiffness, the greater resistance to deformation and lower potential for extension makes comb wax a superior structural material. The mechanical advantage for including propolis and cocoon silk within the comb structure was also investigated. Tensile testing indicates that the resultant composite material is structurally superior, largely due to the presence of silk reinforcement. / Andrew Chakane 2018

Summary Bees, like many other organisms, evolved an endogenous circadian clock, which enables them to foresee daily environmental changes and exactly time foraging flights to periods of floral resource availability. The social lifestyle of a honey bee colony has been shown to influence circadian behavior in nurse bees, which do not exhibit rhythmic behavior when they are nursing. On the other hand, forager bees display strong circadian rhythms. Solitary bees, like the mason bee, do not nurse their offspring and do not live in hive communities, but face the same daily environmental changes as honey bees. Besides their lifestyle mason and honey bees differ in their development and life history, because mason bees overwinter after eclosion as adults in their cocoons until they emerge in spring. Honey bees do not undergo diapause and have a relatively short development of a few weeks until they emerge. In my thesis, I present a comparison of the circadian clock of social honey bees (Apis mellifera) and solitary mason bees (Osmia bicornis and Osmia cornuta) on the neuroanatomical level and behavioral output level. I firstly characterized in detail the localization of the circadian clock in the bee brain via the expression pattern of two clock components, namely the clock protein PERIOD (PER) and the neuropeptide Pigment Dispersing Factor (PDF), in the brain of honey bee and mason bee. PER is localized in lateral neuron clusters (which we called lateral neurons 1 and 2: LN1 and LN2) and dorsal neuron clusters (we called dorsal lateral neurons and dorsal neurons: DLN, DN), many glia cells and photoreceptor cells. This expression pattern is similar to the one in other insect species and indicates a common ground plan of clock cells among insects. In the LN2 neuron cluster with cell bodies located in the lateral brain, PER is co-expressed with PDF. These cells build a complex arborization network throughout the brain and provide the perfect structure to convey time information to brain centers, where complex behavior, e.g. sun-compass orientation and time memory, is controlled. The PDF arborizations centralize in a dense network (we named it anterio-lobular PDF hub: ALO) which is located in front of the lobula. In other insects, this fiber center is associated with the medulla (accessory medulla: AME). Few PDF cells build the ALO already in very early larval development and the cell number and complexity of the network grows throughout honey bee development. Thereby, dorsal regions are innervated first by PDF fibers and, in late larval development, the fibers grow laterally to the optic lobe and central brain. The overall expression pattern of PER and PDF are similar in adult social and solitary bees, but I found a few differences in the PDF network density in the posterior protocerebrum and the lamina, which may be associated with evolution of sociality in bees. Secondly, I monitored activity rhythms, for which I developed and established a device to monitor locomotor activity rhythms of individual honey bees with contact to a mini colony in the laboratory. This revealed new aspects of social synchronization and survival of young bees with indirect social contact to the mini colony (no trophalaxis was possible). For mason bees, I established a method to monitor emergence and locomotor activity rhythms and I could show that circadian emergence rhythms are entrainable by daily temperature cycles. Furthermore, I present the first locomotor activity rhythms of solitary bees, which show strong circadian rhythms in their behavior right after emergence. Honey bees needed several days to develop circadian locomotor rhythms in my experiments. I hypothesized that honey bees do not emerge with a fully matured circadian system in the hive, while solitary bees, without the protection of a colony, would need a fully matured circadian clock right away after emergence. Several indices in published work and preliminary studies support my hypothesis and future studies on PDF expression in different developmental stages in solitary bees may provide hard evidence. / Zusammenfassung Bienen, sowie viele andere Organismen, evolvierten eine innere circadiane Uhr, die es ihnen ermöglicht, tägliche Umweltveränderungen voraus zu sehen und ihre Foragierflüge zu Tageszeiten durchzuführen, wenn sie möglichst viele Blüten besuchen können. Es zeigte sich, dass der soziale Lebensstil der Honigbiene Einfluss auf das rhythmische Verhalten der Ammenbienen hat, die während der Brutpflege keinen täglichen Rhythmus im Verhalten aufweisen. Sammlerbienen auf der anderen Seite zeigen ein stark rhythmisches Verhalten. Solitäre Bienen, wie die Mauerbiene, betreiben keine Brutpflege und leben nicht in einer Staatengemeinschaft, aber sind den gleichen Umweltveränderungen ausgesetzt. Nicht nur Lebensstil, sondern auch Entwicklung und Lebenszyklus unterscheiden sich zwischen Honig- und Mauerbienen. Mauerbienen überwintern als adulte Insekten in einem Kokon bis sie im Frühjahr schlüpfen. Honigbienen durchleben keine Diapause und schlüpfen nach wenigen Wochen der Entwicklung im Bienenstock. In meiner Dissertation vergleiche ich die circadiane Uhr von sozialen Honigbienen (Apis mellifera) und solitären Mauerbienen (Osmia bicornis und Osmia cornuta) auf Ebene der Neuroanatomie und das durch die innere Uhr verursachte rhythmische Verhalten. Erstens charakterisierte ich detailliert die Lage der circadianen Uhr im Gehirn von Honig- und Mauerbiene anhand des Expressionsmusters von zwei Uhrkomponenten. Diese sind das Uhrprotein PERIOD (PER) und das Neuropeptid Pigment Dispersing Factor (PDF). PER wird exprimiert in lateralen Neuronen-Gruppen (die wir laterale Neurone 1 und 2 nannten: LN1 und LN2) und dorsalen Neuronen-Gruppen (benannt dorsal laterale Neurone und dorsale Neurone: DLN und DN), sowie in vielen Gliazellen und Fotorezeptorzellen. Dieses Expressionsmuster liegt ähnlich in anderen Insektengruppen vor und deutet auf einen Grundbauplan der Inneren Uhr im Gehirn von Insekten hin. In der LN2 Neuronen-Gruppe, deren Zellkörper im lateralen Gehirn liegen, sind PER und PDF in den gleichen Zellen co-lokalisiert. Diese Zellen bilden ein komplexes Netzwerk aus Verzweigungen durch das gesamte Gehirn und liefern damit die perfekte Infrastruktur, um Zeitinformation an Gehirnregionen weiterzuleiten, die komplexe Verhaltensweisen, wie Sonnenkompass-Orientierung und Zeitgedächtnis, steuern. Alle PDF Neuriten laufen in einer anterior zur Lobula liegenden Region zusammen (sie wurde ALO, anterio-lobular PDF Knotenpunkt, genannt). Dieser Knotenpunkt ist in anderen Insekten mit der Medulla assoziiert und wird akzessorische Medulla (AME) genannt. Wenige PDF Zellen bilden bereits im frühen Larvalstadium diesen ALO und die Zellzahl sowie die Komplexität des Netzwerks wächst die gesamte Entwicklung der Honigbiene hindurch. Dabei werden zuerst die dorsalen Gehirnregionen von PDF Neuronen innerviert und in der späteren Larvalentwicklung wachsen die Neurite lateral in Richtung der optischen Loben und des Zentralgehirns. Das generelle Expressionsmuster von PER und PDF in adulten sozialen und solitären Bienen ähnelt sich stark, aber ich identifizierte kleine Unterschiede in der PDF Netzwerkdichte im posterioren Protocerebrum und in der Lamina. Diese könnten mit der Evolution von sozialen Bienen assoziiert sein. Zweitens entwickelte und etablierte ich eine Methode, Lokomotionsrhythmen von individuellen Bienen im Labor aufzunehmen, die in Kontakt mit einem Miniaturvolk standen. Diese Methode enthüllte neue Aspekte der sozialen Synchronisation unter Honigbienen und des Überlebens von jungen Bienen, die indirekten sozialen Kontakt zu dem Miniaturvolk hatten (Trophalaxis war nicht möglich). Für Mauerbienen etablierte ich eine Methode Schlupf- und lokomotorische Aktivitätsrhythmik aufzuzeichnen und konnte damit zeigen, dass tägliche Rhythmen im Schlupf durch Synchronisation der circadianen Uhr in Mauerbienen durch Tagestemperatur-Zyklen erzielt werden kann. Des Weiteren präsentiere ich die ersten lokomotorischen Aktivitätsrhythmen von solitären Bienen, die sofort nach ihrem Schlupf einen starken circadianen Rhythmus im Verhalten aufwiesen. Honigbienen brauchten in meinen Experimenten mehrere Tage, um circadiane Rhythmen in Lokomotion zu entwickeln. Ich erstellte die Hypothese, dass Honigbienen zum Zeitpunkt des Schlupfes im Bienenvolk ein noch nicht vollständig ausgereiftes circadianes System besitzen, während solitäre Bienen, die ohne den Schutz eines Volkes sind, direkt nach dem Schlupf eine vollständig ausgereifte Uhr brauchen. Mehrere Hinweise in Publikationen und Vorversuchen unterstützen meine Hypothese. Zukünftige Studien der Entwicklung des PDF Neuronen-Netzwerkes in solitären Bienen unterschiedlicher Entwicklungsstufen könnten dies nachweisen.

Honey bees play an important role in pollination ecology but the conditions of health and genetic purity in North Sweden are not very clear because most honey bees are not native to boreal environments. Emerging studies on insect microbiomes are focusing on the role of lactobacillus as a health factor, given its connection with nectar digestion processes. The aim of this thesis is an assessment of the genetic purity of the western honey bee (Apis mellifera mellifera) and the understanding of implications between non-pathogenic microorganisms and the honey bee's health status. Additionally, the relationships between hive’s colony size, environment, and health status are tested to understand any possible linkages, following the idea that different environments might affect the quantity of lactobacillus and thus immunity and resistance patterns in honey bees. For this project, 15 beehives were sampled in the region of Västerbotten in the summer of 2019/2020, in different types of habitats, with different purposes: analyzing the genetic purity with the wing morphometry method, cultivating the microorganisms that are present in the guts of bees, and comparing the results between urban and agricultural environments. The wing morphometry genetic assessment results showed that up to 80% of the bee keepers who took part in this study breed the subspecies A. mellifera mellifera with no significant level of hybridization with other subspecies. Therefore, honey bee purity status depends on the beekeeper’s choices. Microscopy and the analysis of the microbiomes showed the presence of lactobacillus and minor microorganisms. Cultivable lactic acid bacteria are more present in healthy honey bees in locations with higher plant biodiversity. In fact, the bacillus microbiomes are present in both agricultural and semi-urban areas but are more abundant and diverse in long-lived honey bees from hives in semi-urban area. This could depend on the higher plant diversity in these sites. Finally, the purity of subspecies does not influence adaptive responses or resistance in boreal environments.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21467号 / 農博第2310号 / 新制||農||1064(附属図書館) / 学位論文||H31||N5162(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 平井 伸博, 准教授 赤松 美紀, 教授 森 直樹 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Insects are not mere reflex machines. Instead, they adapt their behaviour flexibly to changing environmental contingencies. Among the insects, honeybees (Apis mellifera) possess an impressive repertoire of cognitive abilities, despite their limited number of neurons. Thanks to the standardization of behavioral, neurobiological, neuroimaging, and genetic methods, bees became a widely used invertebrate model in research. Importantly, the study of their capacities allows us to integrate evidence from an invertebrate species into broader scientific frameworks - often based on vertebrate studies - supporting a deeper understanding of the evolution of certain cognitive mechanisms and their universality. Honeybees can process different information from their environment, such as the numerousness of an array or the relationships – both perceptual and abstract – between objects. Once identified, such relationships allow bees to form distinct categories to which they will refer to implement adaptive choices. An ongoing debate focused on whether numerical abilities in bees are supported by a unified neural mechanism – as for vertebrates - or if multiple segregated mechanisms are involved. Additionally, there is interest in further expanding our knowledge about the extent of bees’ categorization capacities in different contexts. This thesis aims to address these questions, providing evidence that can shed light on the neural organization and limits of honeybees’ cognitive abilities, as well as on potential similarities or differences with other species. In the first two studies, the existence of a general mechanism for the estimation of quantity in honeybees was investigated. Specifically, I addressed the issue of whether bees’ numerical abilities are supported by a general magnitude mechanism that estimates continuous (e.g., space, time, size) and discrete (i.e., number) quantities. In the first study, we investigated the bees' ability to transfer learning from numerical to size dimension. Using appetitive-aversive conditioning, independent groups of free-flying foragers were trained to discriminate between larger and smaller visual numerousness (i.e., 2 vs. 4, 2 vs. 3, 4 vs. 8, 4 vs. 6; 0.5 or 0.67 ratio difference). We then tested the bee's generalization ability with a comparison between stimuli with different sizes and identical numerosity (e.g., 4 larger elements vs. 4 smaller elements). Honeybees spontaneously chose the congruent size with respect to their training. No effect of numerical contrast and ratio difference experienced was found as bees previously reinforced toward the larger numerosity, chose the relatively larger size, and vice versa. These results demonstrated the ability of this insect species to make a transfer from the numerical to the size dimension. Given the possibility of asymmetric relationships between magnitudes, we sought to explore whether honeybees possess the capacity to make the reverse transfer as well, from a continuous (size) to a discrete (number) dimension. Similar to the previous study, free-flying foragers were trained to discriminate between relatively larger vs. smaller squares or diamonds. Their generalization ability over novel shapes (i.e., circles) and novel dimensions (i.e., number) was subsequently tested. Our results confirmed the ability of bees to transfer size discrimination to novel shapes. Moreover, when presented with a 4 vs. 8 elements comparison, bees spontaneously selected the congruent numerosity with respect to their training (i.e., bees trained to select the smaller/larger size, selected the smaller/larger numerosity, respectively). To check for any perceptual cue involvement in bees’ decision-making, different continuous variables covarying with numerosity were controlled for (i.e., total area, contour length, stimulus size, convex hull). Subsequent analyses also revealed no role of spatial frequency in the bees’ behavior. The results revealed a bee’s capacity to transfer between numerical and size dimensions, suggesting the universality of the magnitudes coding mechanism and highlighting the presence of a unified circuit supporting discrete and continuous quantity processing. The second aim of this thesis was to enlarge our knowledge of the ability of bees to spontaneously encode regularities from the physical world. To this purpose, I tested bees' ability to extrapolate the structure of temporally defined odor sequences. In a series of six experiments, the spontaneous and trained ability of bee foragers to learn, memorize, and generalize an odor sequence composed of three distinct odors was tested. A proboscis extension response (PER) conditioning paradigm was employed (i.e., absolute, differential, and generalization). The first two experiments investigated honeybees’ ability to learn an arbitrary odor sequence. Bees were trained to respond to a specific sequence of three odors and then tested for their spontaneous ability to generalize their response to novel sequences with a similar structure but composed of novel odors and to reject novel configurations although composed of familiar odors. The role of a particular odor position in the sequence, the odor-reward temporal closeness, and their possible effects on memory were also investigated in the third experiment. The fourth and fifth experiments aimed to understand the effect of differential conditioning on bees’ learning ability. Lastly, we determined whether a conditioning procedure favouring a generalization strategy could lead to the spontaneous encoding of the internal sequence structure. In general, the results highlighted an early tendency of bees to encode the single odor properties, instead of learning the entire sequence structure, together with a significantly increased response towards the novel odor configurations composed of familiar odors. No effect of the odor’s position or temporal closeness with the reward was apparent. During absolute and differential conditioning, bees likely employed two strategies to memorize the dyad of the first and second elements of the sequence, together with a more general response to novelty. However, the use of a transfer paradigm potentially revealed a weak spontaneous generalization over similar structures one hour after the training, irrespective of the single-element properties. Overall, these results shed light on the strategies employed by bees to solve an odor abstraction task, highlighting the crucial role of the type of conditioning to let them emerge. Altogether, the thesis provides new evidence on honeybees’ cognition. The findings have implications not only for the study of bees’ behavior but also for broader investigations into the universal development of basic cognitive mechanisms and the convergent evolution of similar abilities in small and large brains.

African honeybee workers, Apis mellifera scutellata can activate their ovaries under queenless conditions to produce male (haploid) offspring. In contrast, laying workers of the Cape honeybee, Apis mellifera capensis, produce female (diploid) offspring via thelytokous parthenogenesis. In the early 1990’s colonies of A. m. capensis were transported into the distribution area of A. m. scutellata (corresponding to the summer rainfall region of South Africa), leading to the “capensis calamity”. Laying workers of A. m. capensis invaded and killed colonies of A. m. scutellata leading to losses of thousands of commercial colonies. A survey of the apiaries in the A. m. scutellata region was conducted over 18 months from 1997 to 1998, to determine the extent of the problem. It was found that the parasites were established in many apiaries throughout the distribution range of A. m. scutellata. As the problem seemed to be more severe with commercial and migratory beekeepers, the apiaries surveyed were divided into risk groups related to beekeeping practices. The low risk group included apiaries of beekeepers in areas that are separated from commercial beekeepers and their high risk activities. These low risk colonies were sedentary vs the migration to high risk ares eg. Aloes, sunflower pollination areas, citrus and other fruit pollination areas of the high risk apairies. The apiaries were monitored and records of the colonies’ condition were taken. Samples of workers were collected for dissection. It was found that the low risk group had a lower rate of infection, a higher production of brood and honey and a higher rate of survival over a 12 month period. The significant characteristics for identifying infection of a colony were determined as being the colour of the workers, the brood pattern, the presence of multiple eggs in cells and the presence of the queen. Indeed, the presence of dark workers with a black scutellum, an irregular brood pattern, the presence of multiple eggs in cells and the absence of queen were all prevalent in infected colonies. As sample of workers from all inspected colonies were dissected and the average ovariole counts as well of the development stage of the ovaries proved to be significant variables in the diagnosis. Other variables eg. Ovariole counts, spermatheca size and aggression proved to be not significant, but in conjunction with other variables, could be used for diagnosis. The genetic nature of the invasive parasitic population was determined using polymerase chain reaction (PCR) analysis. Nine loci were tested and the DNA fingerprints of all individuals sampled throughout the summer rainfall region were proved to be identical. This genetic identity led to the descripter of these individuals as a pseudoclone. In contrast, workers of A. m. scutellata were tested with the same loci and showed the normal distribution of an out-breeding population. In order to investigate the spread of the parasite within an apiary, colonies were exposed to heavily infected hives and inspected regularly. Ninety five percent of the colonies had either died or absconded within 12 months. It is concluded that this phenomenon of social parasitism is the consequence of apicaultural activities and that it can be managed by adopting low risk beekeeping practices. / Dissertation (MSc (Zoology and Entomology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted

The European honey bee (Apis mellifera) has been present in Australia for approximately 150 years. For the majority of that time it was assumed this species could only be of benefit to Australia‘s natural ecosystems. More recently however, researchers and conservationists have questioned this assumption. Honey bees are an introduced species and may be affecting native fauna and flora. In particular, native bees have been highlighted as an animal that may be experiencing competition from honey bees as they are of similar sizes and both species require nectar and pollen for their progeny. Most research to date has focused on indirect measures of competition between honey bees and native bees (resource overlap, visitation rates and resource harvesting). The first chapter of this thesis reviews previous research explaining that many experiments lack significant replication and indirect measures of competition cannot evaluate the impact of honey bees on native bee fecundity or survival. Chapters two and four present descriptions of nesting biology of the two native bee species studied (Hylaeus alcyoneus and an undescribed Megachile sp.). Data collected focused on native bee fecundity and included nesting season, progeny mass, number of progeny per nest, sex ratio and parasitoids. This information provided a picture of the nesting biology of these two species and assisted in determining the design of an appropriate experiment. Chapters three and five present the results of two experiments investigating the impact of honey bees on these two species of native bees in the Northern Beekeepers Nature Reserve in Western Australia. Both experiments focused on the fecundity of these native bee species in response to honey bees and also had more replication than any other previous experiment in Australia of similar design. The first experiment (Chapter three), over two seasons, investigated the impact of commercial honey bees on Hylaeus alcyoneus, a native solitary bee. The experiment was monitored every 3-4 weeks (measurement interval). However, beekeepers did not agist hives on sites simultaneously so measurement intervals were initially treated separately using ANOVA. Results showed no impact of honey bees at any measurement interval and in some cases, poor power. Data from both seasons was combined in a Wilcoxon‘s sign test and showed that honey bees had a negative impact on the number of nests completed by H. alcyoneus. The second experiment (Chapter 5) investigated the impact of feral honey bees on an undescribed Megachile species. Hive honey bees were used to simulate feral levels of honey bees in a BACI (Before/After, Control/Impact) design experiment. There was no impact detected on any fecundity variables. The sensitivity of the experiment was calculated and in three fecundity variables (male and female progeny mass and the number of progeny per nest) the experiment was sensitive enough to detect 15-30% difference between control and impact sites. The final chapter (Chapter six) makes a number of research and management recommendations in light of the research findings.

From an apicultural point of view the Cape fynbos is under-utilised and our knowledge of its utilization by the Cape honeybees is incomplete. The key aim of this study was to test the hypothesis that the Cape honeybees utilize the fynbos species as the preferred source of nectar and pollen. Subsidiary aims included distinguishing vegetation communities in the area, identifying pollen and nectar sources, the relationship between brood population and seasonal pollen collection patterns, examining the effect of meteorological factors on pollen collection. The study site was on Rivendell Farm within the Eastern Cape Albany district: an area of high species richness. A checklist of vascular plant species was produced revealing 97 families, 271 genera and 448 species. A classification by two-way indicator species (TWINSPAN) recognized seven vegetation communities: Forest, Bush clumps, Acacia savanna, Grassland, Grassy fynbos, Fynbos and Shrubland. Direct field observations of the foraging of Cape honeybees identified 54 nectar and pollen source plant species. Honeybee pollen loads trapped from four colonies of hives identified 37 pollen source plants of which Metalasia muricata, Eucalyptus grandis, Eucalyptus camaldulensis, Erica chamissonis, Helichrysum odoratissimum, Helichrysum anomalum, Crassula cultrata and Acacia longifolia were the predominant pollen source plants. It was also found that 60% of pollen yield derived from fynbos vegetation. The pollen source plants came from both Cape endemic and from nonendemic species. Thus we reject the hypothesis that Cape honeybees selectively forage fynbos species as a preferred source of pollen and nectar. The examination of the effect of temperature, wind-speed and temperature on pollen collection activity of honeybees revealed that: a temperature range of between 14°C to 26°C was optimal for pollen collection; wind speeds of up to 4m/s were conducive for pollen collection; relative humidity was found to have no significant influence on pollen collection. Pollen collection and brood rearing patterns are positively correlated with flowering intensities, but we found in our Eastern Cape study site that brood rearing was not limited to the spring flowering season but did extend to the end of summer. In order to determine the available nectar yield of common plant species hourly secretion of nectar volumes was measured for 24 hours to determine the variation of available nectar during different times of the day. In all nectar producing species the nectar volume was high in the early morning and declined as the day progressed. We found that the volume of available nectar was affected by prevailing temperature and humidity around the flowers.

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.