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

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Hall, H., 2022. Remote assessment of Varroa presence in honey bee colonies using vibration measurements. PhD, Nottingham Trent University.

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Abstract

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.

Item Type:	Thesis
Description:	This research programme was carried out in collaboration with the University of Warwick.
Creators:	Hall, H.
Date:	September 2022
Rights:	This work is the intellectual property of the author. You may copy up to 5% of this work for private study, or personal, non-commercial research. Any re-use of the information contained within this document should be fully referenced, quoting the author, title, university, degree level and pagination. Queries or requests for any other use, or if a more substantial copy is required, should be directed in the owner(s) of the Intellectual Property Rights.
Divisions:	Schools > School of Science and Technology
Record created by:	Linda Sullivan
Date Added:	21 Jun 2023 08:32
Last Modified:	21 Jun 2023 08:32
URI:	https://irep.ntu.ac.uk/id/eprint/49233