... the contribution of visual flicker to the predator avoidance response of the fiddler crab Uca vomeris . The results illustrate that crabs let purely black or purely white dummies approach significantly closer than black-and-white flickering dummies. We show that this effect complements other factors that modulate...

... – in the compound eye of the fiddler crab Uca vomeris . Using an in vivo pseudopupil method we determined sizes and viewing directions of ommatidia and created a complete eye map of optical and sampling resolution across the visual field. Our results reveal five distinct eye regions (ventral, dorsal,frontal...

... and the failure of identifying a competitor could be very costly. How does an animal decide whether another animal is or is not a threat to a resource or a territory? Fiddler crabs [ Uca vomeris (McNeill)] operate from burrows that they guard and defend vigorously against other crabs. The crabs live in dense...

...Jan M. Hemmi; J. Zeil SUMMARY Using crab-like dummies, we have shown previously that fiddler crabs[ Uca vomeris (McNeill)] defend their burrows against intruders in a burrow-centred frame of reference. The crabs respond whenever an intruder approaches to within a certain distance of the burrow...

... visual field, below the local visual horizon, and against the mudflat surface as background. We filmed events in a colony of Uca vomeris with a normal video camera and an ultraviolet-sensitive camera placed at the eye height of an average crab, approximately 2–3cm above ground. We also used...