A biorobotic approach to modelling celestial cue integration in ball-rolling dung beetles

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This project aims to explore biologically plausible computational models whichmay explain the mechanisms by which dung beetles can maintain a straight bearingwith reference to multiple sky cues as a compass reference. The initial approachis centred on producing an accurate computer simulation of the dung beetle dorsaleye view when presented with different patterns of light with the hypothesis thatthe structure of the beetle eye and immediate optical pathway governs the cueintegration and cue preference differences observed between species. Thispreprocessing will be used to generate a plausible encoding which can be used asinput to the Central Complex model; a model of the Central Complex neuralstructure, thought to be the orientation centre of the beetle brain. While acomputational model is the goal, I aim to implement any resultant model on arobot platform to provide performance data under real skylight conditions.The question arises from studies in behavioural biology conducted at LundUniversity regarding South African ball-rolling dung beetles; specifically, theirorientation behaviour when rolling dung away from the dung pile. Ball-rollingdung beetles use dung for a few purposes, notably as a food source.There is therefore serious competition over the valuable resource. Once a beetlehas formed its ball of dung it picks a direction and rolls the ball away in astraight line to quickly maximise its distance from the dung pile.Dung beetles (like humans) need some external reference to maintain theirbearing. Mounting evidence shows that the reference in use is the sky. Dungbeetles were first shown to use the sun as a directional prompt by Byrne et al.in 2003 but have since been shown to use a variety of celestial cues to maintaintheir straight-line orientation, including: the position of the Moon/Sun, acelestial colour spectrum, the pattern of light polarisation caused by Moon/Sunlight filtering through the atmosphere, and even the the Milky Way galaxy in thesky (visible from their natural habitat). Currently, we understand that theavailable cues are combined in some way and that there is some inherentpreference for different cues between different species; however, there is nobiologically plausible computational model which adequately describes all of theobserved behaviours; this project aims to develop and explore such models.