Colourful Objects Through Animal Eyes

University of Groningen Reflections on colourful ommatidia of butterfly eyes Stavenga, Doekele

Colour thresholds in a coral reef fish

Coral reef fishes are among the most colourful animals in the world. Given the diversity of lifestyles and habitats on the reef, it is probable that in many instances coloration is a compromise between crypsis and communication. However, human observation of this coloration is biased by our primate visual system. Most animals have visual systems that are 'tuned' differently to humans; optimized...

Dynamic polarization vision in mantis shrimps

Gaze stabilization is an almost ubiquitous animal behaviour, one that is required to see the world clearly and without blur. Stomatopods, however, only fix their eyes on scenes or objects of interest occasionally. Almost uniquely among animals they explore their visual environment with a series pitch, yaw and torsional (roll) rotations of their eyes, where each eye may also move largely indepen...

Sex differences in carotenoid status and immune performance in zebra finches

Sex differences in immunity are common throughout the animal kingdom, with males typically showing reduced immune capacity compared with females due to the immunosuppressive action of androgens like testosterone. However, in animals (e.g. birds, fishes) in which immunostimulatory carotenoid pigments are used to develop colourful traits, males tend to circulate higher concentrations of these imm...

Sperm of colourful males are better protected against oxidative stress.

Sperm cells are highly vulnerable to free radicals, and sperm quality and male fertility are critically affected by oxidative stress. Recently, sexual ornaments, particularly carotenoid-based colourful traits, have been proposed to depend on a male's capacity to resist oxidative stress, and thus to signal sperm quality. We conducted an experimental test of this hypothesis on great tits Parus ma...