In recent decades we have seen a string of remarkable discoveries detailing the impressive cognitive abilities of bees (social learning, concept learning and even counting). But should these discoveries be regarded as spectacular because bees manage to achieve human-like computations of visual image analysis and reasoning? Here I offer a radically different explanation. Using theoretical bee brain models and detailed flight analysis of bees undergoing behavioural experiments I counter the widespread view that complex visual recognition and classification requires animals to not only store representations of images, but also perform advanced computations on them. Using a bottom-up approach I created theoretical models inspired by the known anatomical structures and neuronal responses within the bee brain and assessed how much neural complexity is required to accomplish behaviourally relevant tasks. Model simulations of just eight large-field orientation-sensitive neurons from the optic ganglia and a single layer of simple neuronal connectivity within the mushroom bodies (learning centres) generated performances remarkably similar to the empirical result of real bees during both discrimination and generalisation orientation pattern experiments. My models also hypothesised that complex 'above and below' conceptual learning, often used to exemplify how 'clever' bees are, could instead be accomplished by very simple inspection of the target patterns. Analysis of the bees' flight paths during training on this task found bees utilised an even simpler mechanism than anticipated, demonstrating how the insects use unique and elegant solutions to deal with complex visual challenges. The true impact of my research is therefore not merely showing a model that can solve a particular set of generalisation experiments, but in providing a fundamental shift in how we should perceive visual recognition problems. Across animals, equally simple neuronal architectures may well underlie the cognitive affordances that we currently assume to be required for more complex conceptual and discrimination tasks.

A model for the repellent effect of pyrethroid insecticides on insects was developed. Experiments were conducted using a small colony of honey bees in a flight cage. Conditioning to scented feeders allowed the separation of foraging bees from a single colony into treatment and control groups. Permethrin, cypermethrin, fenvalerate and flucythrinate were shown to be contact repellents to honey bees; exposure was primarily to the tarsi and ventral abdomen. The threshold dose of permethrin required to induce repellency was ca. 3.8 ng/bee. Repellency was fully reversible within 24 hours. No permanent effects on either memory or foraging efficiency were observed following acute exposure.

The European honeybee (Apis mellifera) is a managed insect pollinator of global economic importance. Over the last few decades honeybees have been undergoing a major health crisis, with one of the biggest causes the parasitic mite, Varroa destructor and its role in changing the viral landscape of deformed wing virus (DWV), which consists of two major variants: DWV-A and DWV-B. Prior to the start of this project there was limited information known about the mechanisms behind the relationships between Varroa, DWV and honeybees. The overarching aim of this project was to further enhance our understanding of these complex relationships, focusing on the impact of Varroa DWV transmission and differences between the main DWV variants. One of the initial obstacles to understanding these complex interactions was the inability to accurately quantify DWV variants. Prior to the start of this project, there was a need for an accurate assay for the quantification of DWV-A, DWV-B and total DWV, allowing the role of both variants in viral transmission and establishment to be investigated. While primers did exist for DWV quantification, the majority did not distinguish between variants, or provide accurate levels of DWV. Given these challenges in variant detection, a new assay for the quantification of DWV-A, DWV-B and total DWV was designed and validated. The assay consists of an external plasmid standard with distinct sections, for the detection of variants and total DWV. This DWV variant plasmid assay was essential for further transmission studies in this project. DWV variant transmission was explored using a variety of different methods. A new in vitro feeding system was used, to allow investigations into Varroa DWV variant transmission in isolation. The feeding system utilises locust haemolymph, allowing changes in DWV transmission to be detected. In multiple feeding experiments significant changes in DWV transmission were detected. Significant changes in DWV composition within feeding Varroa were detected with decreased levels of DWV, and changing variant levels. Switches in variant composition within mites and transmission rates occurred during Varroa in vitro feeding. These variant switches occurred in both directions from DWV-A to DWV-B, and DWV-B to DWV-A dominance. These changes in mite variant composition corresponded to changes in levels of replicating strands. iv These changes in DWV transmission, composition and replicating strand detection were only seen due to the use of this in vitro feeding system. The in vitro work provided valuable information about Varroa variant transmission and composition changes during feeding but this is not a natural system. Honeybee pupae from a Varroa-free area with extremely low DWV titres provided the opportunity to investigate Varroa variant transmission and pupal DWV establishment. Over 96 hours total DWV levels underwent a 1339408X fold increase, within pupae following Varroa feeding, with a sharp increase after 12 hours, followed by a plateau after 60 hours. Within this time period, DWV-A underwent a similar increase, while DWV-B increased at a much slower rate (33X fold change). In contrast to the in vitro work, mite DWV levels did not decrease during feeding. The impact of natural Varroa cell infestation on L5 larvae was investigated, showing no significant effects between pupal total DWV levels and mite density, and DWV levels between infested and none-infested larvae. However, this lack of significance could be attributed to the use of L5 larvae, which had only undergone a maximum of 24 hours Varroa feeding within the cell. Additionally, the use of two drug treatments (ribavirin and hydroxyurea) to reduce DWV levels was explored. Both drug treatments were tested against Varroa and honeybees, using a variety of methods: immersion (Varroa), injections (honeybees) and feeding (both). While neither drug treatment resulted in consistent DWV decreases, some reduction in DWV levels were seen following Varroa soaking in drug solutions. A significant decrease in DWV was seen in honeybees following bolus and ad libitum feeding of drug treatments. Overall, information and insights have been gained regarding the complex relationship between Varroa, honeybees and DWV. A new DWV variant qPCR assay was developed and utilised in subsequent studies. DWV variant switches in both transmission rates and mite composition were found to occur in in vitro studies. Differences in DWV variant establishment within honeybees were detected following Varroa in vivo feeding, in low DWV pupae. Though the tested drug treatments did not affect DWV levels, this highlights the difficultly facing the establishment of any DWV treatment.

Past studies of honey bee populations, in both natural and laboratory settings have allowed researchers to elucidate the dance language of honey bees within the hive. While the intent and meaning of the waggle dance is thoroughly understood, the area within the hive on which the bees dance is poorly understood. Several factors that may contribute to waggle dancing were studied: substrate, scent and hive entrance proximity. Two separate honey bee colonies were placed in three-frame observation hives. After establishing the dance floor, new experimental conditions were introduced by changing the position of the frames and watching for three days per experimental manipulation. Every experimental manipulation but one was followed by an adjustment period, which lasted at least a couple of days. Dancers eventually resumed dancing close to the hive entrance, though a possible predisposition towards brood and/or capped brood substrates was noted on two occasions. Some bees appeared to follow the old dance floor, but this apparent tendency quickly dissipated. Proximity to hive entrance appears to be the determining factor, and any influence of substrate and scent is secondary.

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.

<p>Propagation methods for honeybee viruses have not changed since these viruses were discovered. There are no suitable cell lines or cell culture techniques available for honeybee viruses. Honeybee viruses have to be manually injected with virus in order for the virus to multiply and be extracted. With the presence of inapparent viruses which could co-infect pupae, a method for pure virus propagations needs to be found. Recombinant baculovirus systems have been used extensively to produce foreign proteins from different viruses using vectors and recombinant technology. In this chapter we inserted the capsid gene from BQCV into a transfer vector under the control of the p10 promoter of Autographa californica. Fractions of the sucrose gradient containing the virus like particles (VLPs) were seen under the electron microscope. A Western blot showed the four capsid proteins at the expected sizes for BQCV capsid. This study therefore has shown that a heterologous system such as baculovirus can be used for virus like particle production. Infectious virus technology has helped gain insight into how viruses work. Using this technology altering honeybee viruses could be used to observe different functionalities of the viruses. An attempt was made to interchange the open reading frames of ABPV and BQCV to observe any changes in virus assembly and infectivity. A fusion PCR strategy was employed to interchange the 5&rsquo / and 3&rsquo / ORFs of APBV and BQCV. The strategy however was unsuccessful. Alternative strategies could improve the chances of obtaining a chimeric virus.</p>

Workers in colonies of European honey bees Apis mellifera L. clean their nestmate's body by allogrooming behavior. This behavior may be initiated by either grooming dancers or by the allogroomers themselves. The first occurs less frequently (ca. 17 %) than the later (83 %). By using the inner edge of mandibles, allogroomers comb the hairy parts around the receiver wing bases, sites around which are unreachable by the receiver herself, and where adult females of the tracheal mite Acarapis woodi and the ectoparasite mite A. dorsalis commonly harbor. There are two groups of allogroomers : the specialist, which grooms six or more nestmates within one bout of allogrooming, and the non-specialist, which grooms fewer nestmates. A specialist that groomed 132 nestmates in one bout was observed in this study. Although allogrooming may be initiated by the grooming dancer, the relationship between the two behaviors is negligible. Worker bees perform allogrooming behavior more as a routine task rather than as a response to the grooming dance. Sunlight intensity, and probably temperature, outside the hive influence allogrooming intensity. The intensity increases during sunny days and decreases at night. It also decreases when the day is cloudy or rainy. An intensity of fourteen events per 1000 workers every two minutes was observed during sunny days, so that all the workers in the colony would be groomed ca. eight times within 24 hours. There is very little temporal basis for allogrooming behavior. It is performed by workers of any age above two days. Any nestmate, regardless of age, can be groomed. However, it was observed that bees of foraging age were groomed less frequently. / Graduation date: 1993

No description available.

The floral and pollination biology of jujubes (Ziziphus mauritiana) and longans (Dimocarpus longan) were studied near Hanoi, Vietnam. Jujube is a protandrous species with three phases of flowering. After a brief asexual phase, anthers dehisce and release pollen in the afternoon of the day of anthesis. Stigmas become most receptive the following day when flowers are actively secreting nectar. Both jujube and longan flowers are visited during the day by insects of many families, particularly honeybees and flies (syrphids, calliphorids, and muscids). Honeybees, Apis cerana, made up 84% of floral visitors to jujube flowers and 47 – 95% to longan inflorescences. Bagging experiments revealed that diurnal insect visitors are very important in fruit production of both jujubes and longans. In jujubes, no fruits were set during the first pollination trial early in the flowering period. Fruit set increased to 0.17% midway through flowering and 2.21% for the trial conducted late in the flowering period. Fruit set recorded one week after anthesis suggested that all types of pollination may result in fruits, but 7 weeks after anthesis only open pollination (unbagged flowers) and diurnal pollination treatments yielded fruits. Most fruits (~97%) were estimated to result from honeybee visits to flowers. Longans are also predominantly pollinated by diurnal insects (~84%), but with minor contributions from wind pollination (8.4%) and self-pollination (7.7%). A. cerana was estimated to contribute 67% of longan pollination. Pollination requirements for 39 Vietnamese crops were reviewed. Most benefit from insect pollination. For 8 crops important in Vietnamese agriculture for which there were sufficient data, crop yields and values were estimated. Honeybee pollination resulted in ~50% of yields of these 8 crops, contributing ~900 millionion USD of their total values. This analysis indicates that the pollination service provided by honeybees is enormous. / Association of Universities and Colleges of Canada (AUCC) and Canadian International Development Agency (CIDA): Tier 2 CIDA-UPCD Project.

<p>Propagation methods for honeybee viruses have not changed since these viruses were discovered. There are no suitable cell lines or cell culture techniques available for honeybee viruses. Honeybee viruses have to be manually injected with virus in order for the virus to multiply and be extracted. With the presence of inapparent viruses which could co-infect pupae, a method for pure virus propagations needs to be found. Recombinant baculovirus systems have been used extensively to produce foreign proteins from different viruses using vectors and recombinant technology. In this chapter we inserted the capsid gene from BQCV into a transfer vector under the control of the p10 promoter of Autographa californica. Fractions of the sucrose gradient containing the virus like particles (VLPs) were seen under the electron microscope. A Western blot showed the four capsid proteins at the expected sizes for BQCV capsid. This study therefore has shown that a heterologous system such as baculovirus can be used for virus like particle production. Infectious virus technology has helped gain insight into how viruses work. Using this technology altering honeybee viruses could be used to observe different functionalities of the viruses. An attempt was made to interchange the open reading frames of ABPV and BQCV to observe any changes in virus assembly and infectivity. A fusion PCR strategy was employed to interchange the 5&rsquo / and 3&rsquo / ORFs of APBV and BQCV. The strategy however was unsuccessful. Alternative strategies could improve the chances of obtaining a chimeric virus.</p>