Local homing of the bumblebee, Bombus terrestris

Lobecke A. Local homing of the bumblebee, Bombus terrestris. Bielefeld: Universität Bielefeld; 2018

Taking a goal-centred dynamic snapshot as a possibility for local homing in initially naïve bumblebees

Lobecke A, Kern R, Egelhaaf M. Taking a goal-centred dynamic snapshot as a possibility for local homing in initially naïve bumblebees. The Journal of Experimental Biology. 2018;221(2): jeb168674.It is essential for central place foragers, such as bumblebees, to return reliably to their nest. Bumblebees, leaving their inconspicuous nest hole for the first time need to gather and learn sufficient information about their surroundings to allow them to return to their nest at the end of their trip, instead of just flying away to forage. Therefore, we assume an intrinsic learning programme that manifests itself in the flight structure immediately after leaving the nest for the first time. In this study, we recorded and analysed the first outbound flight of individually marked naïve bumblebees in an indoor environment. We found characteristic loop-like features in the flight pattern that appear to be necessary for the bees to acquire environmental information and might be relevant for finding the nest hole after a foraging trip. Despite common features in their spatio- temporal organisation, first departure flights from the nest are characterised by a high level of variability in their loop-like flight structure across animals. Changes in turn direction of body orientation, for example, are distributed evenly across the entire area used for the flights without anysystematic relationship to the nest location. By considering the common flight motifs and this variability, we came to the hypothesis that a kind of dynamic snapshot is taken during the early phase of departure flights centred at the nest location. The quality of this snapshot is hypothesised to be ‘tested’ during the later phases of the departure flights concerning its usefulness for local homing

Learning and returning flights of bumblebees Bombus terrestris in an octogonal arena.

Bertrand O, Lobecke A, Egelhaaf M. Learning and returning flights of bumblebees Bombus terrestris in an octogonal arena. Bielefeld University; 2020.How animals acquire, process and combine information about the world to navigate accurately is a fundamental question in biology. A foraging buff-tailed bumblebee *Bombus terrestris*, for instance, will start its journey by leaving its nest situated underground and accessible by a hole of about 1cm diameter. To use visual information on returning trips, the insects need to acquire and memorise it on outbound journeys. Bumblebees engage in peculiar flight manneouvers during outbounds journeys thought to be the time of learning visual information around the nest ("learning flights" or "orientation flights"). At the onset of the PhD project of Anne Lobecke, the development of these flights from naive to experienced individuals has not been described in the litterature. Anne Lobecke recorded the behaviour of individually marked bumblebees *Bombus terrestris* in an octogonal flight arena. Here we provide the trajectories (positions and long-body axis orientations over time) of the bumblebees within the octagonal flight arena together with a 3D model of the arena

Habitual higher order aberrations affect Landolt but not Vernier acuity

Reiniger JL, Lobecke A, Sabesan R, et al. Habitual higher order aberrations affect Landolt but not Vernier acuity. Journal of Vision. 2019;19(5): 11.To assess whether the eye's optical imperfections are relevant for hyperacute vision, we measured ocular wave aberrations, visual hyperacuity, and acuity thresholds in 31 eyes of young adults. Although there was a significant positive correlation between the subjects' performance in Vernier- and Landolt-optotype acuity tasks, we found clear differences in how far both acuity measures correlate with the eyes' optics. Landolt acuity thresholds were significantly better in eyes with low higher order aberrations and high visual Strehl ratios (r(2) = 0.22, p = 0.009), and significantly positively correlated with axial length (r(2) = 0.15, p = 0.03). A retinal image quality metric, calculated as two-dimensional correlation between perfect and actual retinal image, was also correlated with Landolt acuity thresholds (r(2 )= 0.27, p = 0.003). No such correlations were found with Vernier acuity performance (r(2) 0.3). Based on these results, hyperacuity thresholds are, contrary to resolution acuity, not affected by higher order aberrations of the eye