Distance estimation in the third dimension in desert ants

Abstract

Desert ants of the genus Cataglyphis perform large-scale foraging excursions from which they return to their nest by path integration. They do so by integrating courses steered and the distances travelled into a continually updated home vector. While it is known that the angular orientation is based on skylight cues, it still is largely enigmatic how the ants measure distances travelled. We extended the ants' task into the third dimension by training them to walk within an array of uphill and downhill channels, and later testing them on flat terrain, or vice versa. In these tests the ants indicated homing distances that did not correspond to the distances actually travelled, but to the ground distances; that is, to the sum of the horizontal projections of the uphill and downhill segments of the ants' paths. These results suggest a much more sophisticated mechanism of distance estimation than hitherto thought. The ants must be able to measure the slopes of undulating terrain and to integrate this information into their "odometer" for the distance estimation process.

Honeybee navigation: distance estimation in the third dimension

“…These ants are renowned for their ability to perform large-scale foraging excursions in rather featureless surroundings and to navigate back to their nest by using path integration (Wehner and Wehner, 1990). Ants trained to move along a series of uphill and downhill channels, and later tested on flat terrain, indicate homing distances corresponding to the distance traversed in the horizontal plane rather than the distance actually travelled along their undulating path (Wohlgemuth et al, 2001;Wohlgemuth et al, 2002). Similar results were also obtained in experiments that used more complicated three-dimensional mazes (Grah at al., 2005).…”

“…With the desert ant, it would be advantageous to measure distances in the horizontal plane because this measure preserves the relative positions of locations irrespective of the undulations of the terrain (Grah et al, 2005;Wohlgemuth et al, 2001;Wohlgemuth et al, 2002). This scheme works because the ant is earthbound and all locations of interest are located on the ground, irrespective of local height.…”

Integrating two-dimensional paths: do desert ants process distance information in the absence of celestial compass cues?

“…Wehner, 1982;Wehner, 1997;Dacke et al, 2003). Concerning the measurement of travelling distances, evidence is accumulating that Cataglyphis uses idiothetic cues, their odometer seems to be based on a kind of step counter or an efference copy of a locomotor central pattern generator (Wohlgemuth et al, 2001;Wohlgemuth et al, 2002;Thiélin-Bescond and Beugnon, 2005;Wittlinger et al, 2006). Idiothetic information can be used also by some arthropods to identify changes in walking directions (Seyfarth et al, 1982;Mittelstaedt, 1985;Moller and Görner, 1994) (cf.…”

Visual odometry in the wolf spider Lycosa tarantula (Araneae: Lycosidae)

“…Several hymenopteran species have been studied using this method not only in relation to odometry but also with regard to the visual control of flight speed. Among the species studied are honeybees (Apis mellifera) either walking (Schöne, 1996) or flying (Baird et al, 2005;Dacke and Srinivasan, 2007;Esch et al, 2001;Si et al, 2003;Srinivasan et al, 1997;Srinivasan and Zhang, 2004), bumblebees (Bombus terrestris) (Baird et al, 2010), stingless bees (Melipona seminigra) (Hrncir et al, 2003;Eckles et al, 2012) and desert ants [Cataglyphis fortis (Ronacher and Wehner, 1995;Ronacher et al, 2000;Sommer and Wehner, 2004;Steck et al, 2009;Wittlinger et al, 2007;Wohlgemuth et al, 2002) and Melophorus bagoti (Narendra, 2007;Narendra et al, 2007;Narendra et al, 2008;Schwarz and Cheng, 2011;Schwarz et al, 2012)]. …”