Psychometric analysis of the honeybee polarization compass

• Applicant: Dr. James Foster
• Subject Area: Sensory and Behavioural Biology
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 451057640

From microscopic nematode worms that burrow into the soil, to migratory birds that traverse the globe, animals direct their behaviour using external cues. For many animals, the sun provides a reliable frame of reference, unaffected by motion parallax. Sunlight scattered in the upper atmosphere also produces a regular pattern of polarized light, visible even when the sun itself is obscured. Directed behaviours that require movement at a fixed bearing across a range of conditions are problems faced by animals and robots alike. Many animals use the pattern of polarized skylight, imperceptible to humans, as a compass reference. Insects in particular appear well-adapted to orient to polarized skylight. Honeybees interpret this pattern with their internal ‘polarization compass’, which allows them not only to orient using the entire skylight pattern, but to remain oriented when presented with small patches of polarized skylight 5° in diameter, one of only two animal species demonstrated to do so to date. Honeybees provide a unique opportunity to study a sophisticated skylight- polarization compass in an accessible, domesticated species. Much previous work on the honeybee polarization compass focussed on the decision “rules” used to interpret patches of polarized skylight under optimal conditions. However, high solar elevations, cloud cover and haze can distort and degrade this pattern. In this project, I will investigate how the honeybee overcomes these challenges,extending the model for the honeybee polarization compass by measuring its limiting parameters. I will address how the degree of polarization affects orientation accuracy, whether pattern properties near the zenith aid unambiguous orientation, and how spatial resolution affects orientation under challenging conditions. In doing so, I will construct a comprehensive model for the honeybee polarization compass, characterised by critical parameters that can be measured and compared across other insect species and applied to artificial navigation systems.

• DFG Programme: Research Grants