Über die orientierung von Uca tangeri eydoux im Freiland

High e-vector acuity in the polarisation vision system of the fiddler crabUca vomeris

“…For example, the relatively unobstructed sky provides strong celestial polarisation cues potentially useful for orientation and navigation (Wehner and Labhart, 2006), and the shiny cuticle of conspecifics provides reflected polarised light that may be useful for differentiating harmless neighbours from dangerous competitors (Zeil and Hofmann, 2001) (see Discussion). In common with many crustaceans, fiddler crabs are thought to be polarisation sensitive (Altevogt and von Hagen, 1964;Korte, 1965;Herrnkind, 1968;Zeil and Hofmann, 2001). Anatomical studies reveal that their eyes possess the typical crustacean organisation of eight light-sensitive retinula (R) cells, with cells R1-7 contributing stacked, orthogonally oriented microvillar layers, capped at the distal end with a single small R8 cell (Alkaladi, 2008).…”

“…Except for some brief early behavioural studies (Altevogt and von Hagen, 1964;Korte, 1965;Herrnkind, 1968), there have been few investigations into polarisation vision in this genus and no attempt to measure the capabilities or limitations of this sensory modality. To address this, we used a liquid crystal display (LCD) monitor, modified to present polarisation-only stimuli (Glantz and Schroeter, 2006;Pignatelli et al, 2011) to tethered fiddler crabs fixed in position over a freely moving treadmill (Buchner, 1976;Hedwig and Poulet, 2004;Oliva et al, 2007).…”

Topography of vision and behaviour

“…Altevogt and von Hagen, 1964;von Hagen, 1967;Land and Layne, 1995a;Land and Layne, 1995b;Hemmi and Zeil, 2003a;Hemmi and Zeil, 2003b), mate choice (Detto et al, 2006) and courtship signalling (How et al, 2007;How and Hemmi, 2008). These behaviours are limited in different ways by the capabilities and accuracy of the visual system (e.g.…”

Fiddler crabs accurately measure two-dimensional distance over three-dimensional terrain

“…A striking example of central-place foraging occurs in the fiddler crabs (genus Uca), which accurately and continuously monitor their burrow location, and align their bodies with its direction, even when they cannot see it (Hemmi and Zeil, 2003;Land and Layne, 1995;Layne et al, 2003a;Zeil, 1998). It is now well established that they do this using PI (Altevogt and von Hagen, 1964;Cannicci et al, 1999;von Hagen, 1967;Layne et al, 2003b;Walls and Layne, 2009;Zeil, 1998).…”