Description of the thesis topic

Pollinating insects, like bees, provide a major ecosystem service that we need to preserve. By moving from flower to flower, these insects ensure plant reproduction, a phenomenon vital to the functioning of our terrestrial ecosystems. Despite over a century of research into bee behavior, very little is known about how these insects move and interact in landscapes (Collett et al. 2013). Understanding these behaviors is necessary to understand and act on pollination. The main difficulty is to measure the movements of these small animals (a few centimetres long), which can travel several kilometers to visit hundreds of flowers, several times a day for several weeks. In recent years, radar systems have been proposed to locate one insect at a time, in 2D, over several hundred meters (Reynolds et al. 1996; Capaldi et al. 2000; Lihoreau et al. 2012; Brebner et al. 2021). Although this is an important first step, it remains a major challenge to track several insects at once in 3D.

The aim of the thesis is to test a system for tracking the trajectories of several insects both in 3D and in the field using harmonic radars. To achieve this, the thesis will combine technical developments based on existing radar prototypes, with field experiments to validate the system with insects (honey bees and bumblebees).

References

Brebner JS, Makinson JC, Bates OK, Rossi N, Lim KS, Dubois T, Gomez-Moracho T, Lihoreau M, Chittka L, Woodgate JL (2021) Bumble bees strategically use ground level linear features in navigation. Animal Behaviour 179:147-160.

Capaldi EA, Smith AD, Osborne JL, Fahrbach SE, Farris SM, Reynolds DR, Edwards AS, Martin A, Robinson GE, Poppy GM, Riley JR (2000) Ontogeny of orientation flight in the honeybee revealed by harmonic radar. Nature 403:537-540.

Collett M, Chittka L, Collett TS (2013) Spatial memory in insect navigation. Current Biology 23: R789-R800.

Lihoreau M, Raine NE, Reynolds AM, Stelzer RJ, Lim KS, Smith AD, Osborne JL, Chittka L. Radar tracking and motion-sensitive cameras on flowers reveal the development of pollinator multi-destination routes over large spatial scales. PloS Biology 10: e1001392.

Riley JR, Smith AD, Reynolds DR, Edwards AS, Osborne JL, Williams IH, Carreck NL, Poppy GM (1996) tracking bees with harmonic radar. Nature 379:29-30.

Work Context

This work will form part of the Bee-Move ERC project (doi :10.3030/101002644), a collaboration between two Toulouse laboratories: the Centre de Recherche sur la Cognition Animale (CRCA) and the Laboratoire d'Analyse et d'Architecture des Systèmes (LAAS CNRS). The candidate will join an international, interdisciplinary team (electronic engineering, computational biology, ethology, ecology) working to understand pollinator movements and their impact on plant reproduction. Work will be carried out under the supervision of Mathieu Lihoreau (DR CNRS - CRCA) and Hervé Aubert (Prof - LAAS-CNRS).

Constraints and risks

- occasional field work
- low risk of being stung by insects

Additional Information

http://www.mathieu-lihoreau.com/bee-move/