The aim of this PhD is to contribute to the understanding of antennal hearing in insects. To this end, Confocal Laser Scanning Microscopy (CLSM), Finite Element Modelling (FEM) and Laser Doppler Vibrometry (LDV) were employed. The combination of the first two allows, in absence of prior knowledge of the material properties of mosquito or midge antennae, to assess the material structure and to gauge which impact this distribution can have on the antenna's mechanical behaviour in response to sound. It was revealed that, rather than a simple beam of uniform cuticle, the antennae of the insects studied had patterns and distributions of hard and soft ring elements along the length of their antennae. These properties were simulated with FEM and showed that they can strongly influence the resonant frequency of the antennae. Further investigations were done on the vibrational behaviour of these insects with LDV. The males of T. brevipalpis, An. arabiensis and An. gambiae demonstrated strong self-oscillation with high Q-factors. Unlike the mosquitoes, vibrometry of C. riparius showed no relevant self-oscillation of the antenna. Female T. brevipalpis produced self-oscillation but weaker than the male. The three-dimensional pattern of self-oscillation in all investigated mosquito species follows a distorted elliptical path. When stimulated with sound, the self-oscillating antennae exhibited classic nonlinear behaviour such as entrainment and down-modulation. Taken together, this thesis highlights the complex mechanics of acoustic reception in mosquitoes and midges, both mechanically and structurally.
|Date of Award||14 Feb 2020|
- University Of Strathclyde
|Sponsors||University of Strathclyde|
|Supervisor||Joseph Jackson (Supervisor) & James Windmill (Supervisor)|