Navigation in wood ants Formica japonica: context dependent use of landmarks

Abstract

Wood ants Formica japonica can steer their outbound (foraging) and inbound (homing) courses without using celestial compass information, by relying exclusively on landmark cues. This is shown by training ants to run back and forth between the nest and an artificial feeder, and later displacing the trained ants either from the nest (when starting their foraging runs: outbound full-vector ants) or from the feeder (when starting their home runs: inbound full-vector ants) to various nearby release sites. In addition, ants that have already completed their foraging and homing runs are displaced after arrival either at the feeder (outbound zero-vector ants) or at the nest (inbound zero-vector ants), respectively, to the very same release sites. Upon release, the full-vector ants steer their straight courses by referring to panoramic landmark cues, while the zero-vector ants presented with the very same visual scenery immediately search for local landmark cues defining their final goal. Hence, it depends on the context, in this case on the state of the forager's round-trip cycle, what visual cues are picked out from a given set of landmarks and used for navigation.

Vector-based and landmark-guided navigation in desert ants inhabiting landmark-free and landmark-rich environments

“…The amount of the home vector actually paid out by M. bagoti after displacement to novel territory is certainly not a constant [44% in Narendra's study (Narendra, 2007a)], but most likely depends on the amount of mismatch between the landmark panoramas at the training and test site. When wood ants Formica japonica (Fukushi, 2001;Fukushi and Wehner, 2004) and rainforest ants Gigantiops destructor (Beugnon et al, 2005) were tested in somewhat similar experimental paradigms, they relied on their home vector even less than M. bagoti did in Narendra's displacement experiments (Narendra, 2007a). These results fall into line with the negative correlation between landmark density and the proportion of the home vector run-off: a high density of highly conspicuous landmarks prevails in the woodland environments of the two latter species.…”

Resource discovery in ant communities: do food type and quantity matter?

“…For instance, some species rotate or constrain the routes that foragers follow, resulting in greater search thoroughness and minimised search overlap (Bernstein, 1975;Franks & Fletcher, 1983;Fresneau, 1985;Buchkremer & Reinhold, 2008). Such searches are guided by polarised light (Wehner, 1997), the sun (Müller & Wehner, 2007), magnetic fields (Banks & Srygley, 2004), and habitat landmarks (Judd & Collett, 1998;Fukushi & Wehner, 2004). It is less clear how frequently directed searches rely on cues directly associated with the resource itself.…”

Do ants need to be old and experienced to teach?

“…For example, many insects learn landmarks to help them navigate in both directions between their nests and foraging sites (Collett et al, 2003;Fukushi and Wehner, 2004). It is therefore not implausible that certain insects might improve their ability to perform certain tasks, i.e.…”