PUB - Publikationen an der Universität Bielefeld

Many animals need to orient and navigate in our three dimensional world to find food, shelter or their home location. Flying insects like bumblebees master these task despite their relatively small brain size. They acquire visual memories of their nest location, well hidden from predators, to return home after their forag- ing trips. With this thesis I contribute to the field of neuroethological research investigating the underlying mechanisms of flying insects such as bumblebees during orientation and navigation to fulfil their daily task of learning, foraging, and homing. The first parts focus on how flying insects use their first out- bound flights to learn the surroundings of their nest. A comprehensive review of the current literature on learning flights provides the basis for an empirical study investigating the influence of the structure of the nest surrounding. When the nest is surrounded by a dense object arrangement, bumblebees prioritise altitude gain over the increase of horizontal distance to the nest. They also look in the direction of the nest location mostly above the surrounding objects, suggesting that those view could be used for later returns. Homing models based on visual memories were used to evaluate the efficiency of aerial views. The findings supported the use of views above the objects instead of ground- level views. However, behavioural experiments showed that the bees rather used lower altitudes to return home. Lastly, the localisation of a goal, e.g. a food source, in three dimensions showed that while bees are able to localise a goal, they are less precise than in two dimensions. In addition, they can learn the height of a goal location, likely with the use of optic flow of the ground floor generated by the bees own movements. In summary, bumblebees actively change their flight altitude during learning, foraging and homing depending on the structure of their environments. Future research is needed to further investigate the mechanisms of navigation in all three dimensions.