The Dung Beetle Dance: An Orientation Behaviour?

Cataglyphis ants are renowned for their impressive navigation skills, which have been studied in numerous experiments during forward locomotion. However, the ants' navigational performance during backward homing when dragging large food loads has not been investigated until now. During backward locomotion, the odometer has to deal with unsteady motion and irregularities in inter-leg coordination. The legs' sensory feedback during backward walking is not just a simple reversal of the forward stepping movements: compared with forward homing, ants are facing towards the opposite direction during backward dragging. Hence, the compass system has to cope with a flipped celestial view (in terms of the polarization pattern and the position of the sun) and an inverted retinotopic image of the visual panorama and landmark environment. The same is true for wind and olfactory cues. In this study we analyze for the first time backwardhoming ants and evaluate their navigational performance in channel and open field experiments. Backward-homing Cataglyphis fortis desert ants show remarkable similarities in the performance of homing compared with forward-walking ants. Despite the numerous challenges emerging for the navigational system during backward walking, we show that ants perform quite well in our experiments. Direction and distance gauging was comparable to that of the forwardwalking control groups. Interestingly, we found that backward-homing ants often put down the food item and performed foodless search loops around the left food item. These search loops were mainly centred around the drop-off position (and not around the nest position), and increased in length the closer the ants came to their fictive nest site.

Section: Open Field Experimentsmentioning

confidence: 73%

How to find home backwards? Navigation during rearward homing of Cataglyphis fortis desert ants

Pfeffer

Wittlinger

2016

“…Learning flights of flying hymenoptera include repeated arcs, loops and turn-backs (honeybees : Becker, 1958;Capaldi and Dyer, 1999;Capaldi et al, 2000;Degen et al, 2015Degen et al, , 2016Lehrer, 1991Lehrer, , 1993Opfinger, 1931;Vollbehr, 1975;wasps: Peckham and Peckham, 1898;Stürzl et al, 2016;Tinbergen, 1932;Zeil, 1993a,b;Zeil et al, 1996;bumblebees: Collett et al, 2013;Hempel de Ibarra et al, 2009;Philippides et al, 2013;Riabinina et al, 2014;Robert et al, 2017;Wagner, 1907). Dung beetles perform rotations about their vertical axis before rolling a ball away from the dung pile (Baird et al, 2012), during which they take a snapshot of the celestial scenery (el Jundi et al, 2016). Desert spiders also perform learning walklike behavior: they leave their burrows in sinusoidal paths when departing to unfamiliar terrains (Nørgaard et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

Species-specific differences in the fine structure of learning walk elements inCataglyphisants

Fleischmann

Grob

Wehner

et al. 2017

123

Cataglyphis desert ants are famous navigators. Like all central place foragers, they are confronted with the challenge to return home, i.e. relocate an inconspicuous nest entrance in the ground, after their extensive foraging trips. When leaving the underground nest for the first time, desert ants perform a striking behavior, so-called learning walks that are well structured. However, it is still unclear how the ants initially acquire the information needed for sky-and landmark-based navigation, in particular how they calibrate their compass system at the beginning of their foraging careers. Using high-speed video analyses, we show that different Cataglyphis species include different types of characteristic turns in their learning walks. Pirouettes are full or partial rotations (tight turns about the vertical body axis) during which the ants frequently stop and gaze back in the direction of the nest entrance during the longest stopping phases. In contrast, voltes are small walked circles without directed stopping phases. Interestingly, only Cataglyphis ant species living in a cluttered, and therefore visually rich, environment (i.e. C. noda and C. aenescens in southern Greece) perform both voltes and pirouettes. They look back to the nest entrance during pirouettes, most probably to take snapshots of the surroundings. In contrast, C. fortis inhabiting featureless saltpans in Tunisia perform only voltes and do not stop during these turns to gaze back at the nest -even if a set of artificial landmarks surrounds the nest entrance.

“…How dung beetles analyze the skylight polarization pattern via their dorsal rim area is still poorly understood, but before rolling its ball away from the dung pile, S. lamarcki performs a series of horizontal rotations on top of its ball, referred to as the dung beetle dance (Baird et al, 2012). These scanning movements could aid the insects in analyzing the celestial polarization pattern (Wehner, 1989; …”

Section: Discussion Orientation To Polarized Skylightmentioning

confidence: 99%

Diurnal dung beetles use the intensity gradient and the polarization pattern of the sky for orientation

Jundi

Smolka

Baird

et al. 2014

Self Cite

To escape competition at the dung pile, a ball-rolling dung beetle forms a piece of dung into a ball and rolls it away. To ensure their efficient escape from the dung pile, beetles rely on a 'celestial compass' to move along a straight path. Here, we analyzed the reliability of different skylight cues for this compass and found that dung beetles rely not only on the sun but also on the skylight polarization pattern. Moreover, we show the first evidence of an insect using the celestial light-intensity gradient for orientation. Using a polarizer, we manipulated skylight so that the polarization pattern appeared to turn by 90 deg. The beetles then changed their bearing close to the expected 90 deg. This behavior was abolished if the sun was visible to the beetle, suggesting that polarized light is hierarchically subordinate to the sun. When the sky was depolarized and the sun was invisible, the beetles could still move along straight paths. Therefore, we analyzed the use of the celestial light-intensity gradient for orientation. Artificial rotation of the intensity pattern by 180 deg caused beetles to orient in the opposite direction. This lightintensity cue was also found to be subordinate to the sun and could play a role in disambiguating the polarization signal, especially at low sun elevations.