Anglia Ruskin University

Professor Mike Cole, Professor Roger Buckley, Dr Charlie Nevison, Dr Andrew Smith, Dr Ebi Osuobeni and Professor Shahina Pardhan.

Collaboration between Department of Life Sciences, Ocular Disease and Opthalmic Epidemiology and Department of Vision and Hearing Sciences.

Focus:

• To investigate the ecological implications of the various types of colour vision in New World monkeys
• Relationship between fruit colouration and colour vision status of consumers
• Probe fitness consequences of colour vision status: Fruit foraging, Prey foraging, Predator detection, Spatial ecology.
• Colour vision frequencies in wild primates
• Heterozygote advantage in the maintenance of colour vision polymorphism in New World monkeys
• Niche partitioning and colour vision phenotypes
• To measure colour vision in horses

There is limited evidence that horses cannot differentiate between white, yellow and green but that they can between red and blue. Some studies have shown that in show jumping, competition horses are more likely to stop at fences of the former colour than the latter, and that contrast between the colour of the fence and the jumping surface is also an important factor. Where the colour contrast is low, the horse is more likely to stop, run out, or otherwise try to avoid the fence. This project would:

• Establish, using numerical systems (for example tristimulus values), the colour of the fences that the horse was being asked to jump.
• Score horses in competition on successful jump, stop, run out, or other evasion.
• Assess, using numerical systems, the contrast between the fence colour and the surface colour to establish whether there is a correlation between behaviour and contrast.
• Assess colour vision in the riders to determine whether this influences the jumping outcome.

Such work will inform the equestrian community who currently use different jumps on different surfaces to select team members for various levels of competition. Since there are often large amounts of money at stake, the study will increase the objectivity in the ability to select a competitive team by standardising the jumping round so that the variables are the horse and rider rather than these two plus the colour of the jumps and the surface from which the jump is made. The study would then be extended into cross country competitions and the eventing community. Such work, should, in principle, be of interest to, for example, the BSJA, The BHS, World Horse Welfare and British Evening.

Within placental mammals, trichromacy is unique amongst primates: all other species so far examined are either dichromats or monochromats. It has been hypothesized that the evolution of trichromatic colour vision by the majority of primate species is a direct result of the chromatic signals produced by fruits or leaves. For an animal to feed on fruits it has first to detect them against a background of leaves. Vision and olfaction are probably the principal senses employed. Yet despite its theoretical advantages, trichromacy is not uniform within the primates. Whilst all catarrhines so far studied are trichromatic, all platyrrhines (New World monkeys), with the two exceptions of howler (Alouatta spp. - uniformly trichromatic) and night monkeys (Aotus spp. - uniformly monochromatic) and some strepsirhines, have a polymorphic colour vision system. All males and homozygous females are dichromats, whilst heterozygous females are trichromats.