Honey Bee Health

Over the past decade, the worldwide decline in honey bee populations has been an important issue due to its implications for beekeeping and honey production. Honey bee pathologies are continuously studied by researchers, in order to investigate the host–parasite relationship and its effect on honey bee colonies. For these reasons, the interest of the veterinary community towards this issue has increased recently, and honey bee health has also become a subject of public interest. Bacteria, such as Melissococcus plutonius and Paenibacillus larvae, microsporidia, such as Nosema apis and Nosema ceranae, fungi, such as Ascosphaera apis, mites, such as Varroa destructor, predatory wasps, including Vespa velutina, and invasive beetles, such as Aethina tumida, are “old” and “new” subjects of important veterinary interest. Recently, the role of host–pathogen interactions in bee health has been included in a multifactorial approach to the study of these insects’ health, which involves a dynamic balance among a range of threats and resources interacting at multiple levels. The aim of this Special Issue is to explore honey bee health through a series of research articles that are focused on different aspects of honey bee health at different levels, including molecular health, microbial health, population genetic health, and the interaction between invasive species that live in strict contact with honey bee populations

Remote assessment of Varroa presence in honey bee colonies using vibration measurements

Honey bee colony monitoring techniques that use hive-based sensors to continuously and remotely measure a range of parameters are increasingly being published. Non-invasive surveillance methods for the identification of Varroa destructor presence and infestation levels are, however, not as well-studied. Varroa mites adversely affect honey bees in several ways, and regular monitoring of their population is critical for successful control. The work carried out in this thesis explores the use of accelerometer sensors and vibration measurements as a non-invasive Varroa detection method. The capture of honey bee vibrations associated with infections of a bee virus (Chronic bee paralysis virus (CBPV)) is also investigated, as Varroa are known to vector approximately 20 honey bee diseases and their associated variants. The answers to three main questions are sought throughout this work: 1) can accelerometers be used to detect vibrations originating from Varroa?, 2) if so, can these vibrations be used as a remote mite monitoring tool?, and 3) do observable honey bee virus symptoms produce detectable vibrations? To conduct this investigation, accelerometers were attached to a variety of substrates and linked to a camera, for simultaneous video and vibration capture, allowing the characterisation of numerous Varroa and honey bee vibrations. The waveform data was transformed into spectrogram and two-dimensional-Fourier-transform (2DFT) images, which were used as a main analysis tool for vibrational feature identification. Principal component and discriminant function analyses were implemented for the purpose of discriminating between groups of vibrational signals and for automatic detection using machine learning within long-term recordings of freshly collected, capped brood-comb. This work demonstrates that accelerometers can detect vibrations generated by minute (1-2mm, 0.42mg) mite individuals, and in the process has enabled the discovery of a novel Varroa behaviour (jolting) that produces a unique vibrational trace. Pulses of interest were carefully characterised in terms of their visible features, periodicity, strength, and time duration. These were then used as search tools for mite detection purposes. The exciting discovery of the jolting behaviour strongly suggests that Varroa can transmit functional vibrations. Continuing to investigate and understand this phenomenon may lead, amongst other things, to novel methods of mite control in the future. These explorations showcase the potential for Varroa vibration capture in remote mite monitoring, laying the groundwork for future analysis. This thesis also demonstrates the many advantages of the lesser used 2DFT image in animal vibration research, promoting its use. In relation to question 3 and the capture of vibrations associated with viral symptoms, no specific vibrational features were identified that could be linked to honey bee trembling, an observable symptom of CBPV. Nevertheless, the results of this chapter (4) promoted the use of 2DFTs in honey bee vibrational monitoring and endorsed solutions for future improvement to this analysis. The 2DFT was also successfully implemented following the discovery of a novel honey bee vibration, here coined the 'purr' (chapter 5). This work encompasses the pursuit of knowledge in the recently evolved subject of biotremology, to compliment the growing field of remote honey bee colony monitoring, and particularly that of non-invasive Varroa detection. A better understanding of both honey bee and Varroa behaviours and biology has been established, promoting the importance of vibration research in these closely entwined species. The value and scope of accelerometer use has here been strengthened through the detection of Varroa vibrations, supporting its growing application in colony monitoring

Descending Octopaminergic Neurons in the Stick Insect: Their Inputs and their Output Effects on the Locomotor System

The neural networks controlling locomotion (walking) must exhibit a high degree of flexibility for task-specific adaptation of behavior to environmental influences and changes in internal state. Neuromodulatory influences are very important for this flexibility, as they can regulate the activity of all neurons in the walking system and the strengths of their synaptic connections. To fully understand the neural control of walking, it is crucial to identify the neurons that release neuromodulators and to determine their activity patterns during behavior and analyze the properties of their output effects. Octopamine, one such neuromodulator, is considered the invertebrate homolog to the vertebrate noradrenaline. It is a significant modulator in insect locomotor systems, both acting in the peripheral and central nervous systems. Octopamine modulates muscle metabolism, neuromuscular transmission, sensory sensitivity, excitability of motor neurons, and activity in the central pattern generating networks that control locomotion. The neural source of octopamine acting in the central nervous system of insect thoracic segments has not yet been identified. Thus, it is unknown to what extent effects of application of octopamine to thoracic ganglia in previous studies reflect the physiological role of octopamine. In the current thesis, I hypothesized that dorsal unpaired median neurons with bilaterally descending axons (desDUM neurons) are a source of octopaminergic modulation of activity in thoracic neural networks for the control of walking in the stick insect Carausius morosus. I revealed the morphology of desDUM neurons in the gnathal ganglion by intracellular staining. Employing the newly developed method of direct MALDI-TOF mass spectrometry, I could show that stick insect desDUM neurons are octopaminergic. Using semi-intact preparations and intracellular recordings of desDUM neurons, I found that they are phasically activated during six-legged walking and single-leg stepping. The phasic excitatory input to desDUM neurons during walking does not arise from coupling to activity of mesothoracic central pattern generating networks, but most likely from activation of mechanosensory organs of all six legs. Passive leg movement and stimulation of mesothoracic campaniform sensilla excited desDUM neurons. Furthermore, stimulation of the mesothoracic femoral chordotonal organ (fCO) had a weak excitatory influence on their activity. Further, I investigated the output effects of desDUM neurons on reflex-evoked, spontaneous, and centrally generated activity of mesothoracic motor neurons with activation of single desDUM neurons. I could show that distinct desDUM neurons mediate differential effects. Some neurons induce a decrease and others an increase, in the magnitude of reflex-induced motor neuron activity. The neurons which mediated an excitatory influence additionally increased the frequency of reversal of an fCO-induced postural reflex. Some desDUM neurons mediated an increase in the frequency of centrally generated rhythmic motor neuron activity. Collectively, the results of the current thesis provide a comprehensive characterization of desDUM neurons and their complex roles in the stick insect locomotor system. The identity of direct neural target structures for the modulatory action of desDUM neurons, as well as the net output effects of the entire population of desDUM neurons during walking remain open questions. In future experiments, genetic access to desDUM neurons could aid in the activation, silencing, or visualization of their activity, which would collectively contribute to comprehensive answers to the open questions

Activation of the pro-resolving receptor Fpr2 attenuates inflammatory microglial activation

Poster number: P-T099 Theme: Neurodegenerative disorders & ageing Activation of the pro-resolving receptor Fpr2 reverses inflammatory microglial activation Authors: Edward S Wickstead - Life Science & Technology University of Westminster/Queen Mary University of London Inflammation is a major contributor to many neurodegenerative disease (Heneka et al. 2015). Microglia, as the resident immune cells of the brain and spinal cord, provide the first line of immunological defence, but can become deleterious when chronically activated, triggering extensive neuronal damage (Cunningham, 2013). Dampening or even reversing this activation may provide neuronal protection against chronic inflammatory damage. The aim of this study was to determine whether lipopolysaccharide (LPS)-induced inflammation could be abrogated through activation of the receptor Fpr2, known to play an important role in peripheral inflammatory resolution. Immortalised murine microglia (BV2 cell line) were stimulated with LPS (50ng/ml) for 1 hour prior to the treatment with one of two Fpr2 ligands, either Cpd43 or Quin-C1 (both 100nM), and production of nitric oxide (NO), tumour necrosis factor alpha (TNFα) and interleukin-10 (IL-10) were monitored after 24h and 48h. Treatment with either Fpr2 ligand significantly suppressed LPS-induced production of NO or TNFα after both 24h and 48h exposure, moreover Fpr2 ligand treatment significantly enhanced production of IL-10 48h post-LPS treatment. As we have previously shown Fpr2 to be coupled to a number of intracellular signaling pathways (Cooray et al. 2013), we investigated potential signaling responses. Western blot analysis revealed no activation of ERK1/2, but identified a rapid and potent activation of p38 MAP kinase in BV2 microglia following stimulation with Fpr2 ligands. Together, these data indicate the possibility of exploiting immunomodulatory strategies for the treatment of neurological diseases, and highlight in particular the important potential of resolution mechanisms as novel therapeutic targets in neuroinflammation. References Cooray SN et al. (2013). Proc Natl Acad Sci U S A 110: 18232-7. Cunningham C (2013). Glia 61: 71-90. Heneka MT et al. (2015). Lancet Neurol 14: 388-40

Exploring Animal Behavior Through Sound: Volume 1

This open-access book empowers its readers to explore the acoustic world of animals. By listening to the sounds of nature, we can study animal behavior, distribution, and demographics; their habitat characteristics and needs; and the effects of noise. Sound recording is an efficient and affordable tool, independent of daylight and weather; and recorders may be left in place for many months at a time, continuously collecting data on animals and their environment. This book builds the skills and knowledge necessary to collect and interpret acoustic data from terrestrial and marine environments. Beginning with a history of sound recording, the chapters provide an overview of off-the-shelf recording equipment and analysis tools (including automated signal detectors and statistical methods); audiometric methods; acoustic terminology, quantities, and units; sound propagation in air and under water; soundscapes of terrestrial and marine habitats; animal acoustic and vibrational communication; echolocation; and the effects of noise. This book will be useful to students and researchers of animal ecology who wish to add acoustics to their toolbox, as well as to environmental managers in industry and government

Exploring Animal Behavior Through Sound: Volume 1

This open-access book empowers its readers to explore the acoustic world of animals. By listening to the sounds of nature, we can study animal behavior, distribution, and demographics; their habitat characteristics and needs; and the effects of noise. Sound recording is an efficient and affordable tool, independent of daylight and weather; and recorders may be left in place for many months at a time, continuously collecting data on animals and their environment. This book builds the skills and knowledge necessary to collect and interpret acoustic data from terrestrial and marine environments. Beginning with a history of sound recording, the chapters provide an overview of off-the-shelf recording equipment and analysis tools (including automated signal detectors and statistical methods); audiometric methods; acoustic terminology, quantities, and units; sound propagation in air and under water; soundscapes of terrestrial and marine habitats; animal acoustic and vibrational communication; echolocation; and the effects of noise. This book will be useful to students and researchers of animal ecology who wish to add acoustics to their toolbox, as well as to environmental managers in industry and government