Can color vision variation explain sex differences in invertebrate foraging by capuchin monkeys?

Invertebrates are the main source of protein for many small-to-medium sized monkeys. Prey vary in size, mobility,degree of protective covering, and use of the forest, i.e. canopy height, and whether they are exposed or embed themselves insubstrates. Sex-differentiation in foraging patterns is well documented for some monkey species and recent studies find that colorvision phenotype can also affect invertebrate foraging. Since vision phenotype is polymorphic and sex-linked in most New Worldmonkeys - males have dichromatic vision and females have either dichromatic or trichromatic vision - this raises the possibilitythat sex differences are linked to visual ecology. We tested predicted sex differences for invertebrate foraging in white-facedcapuchins Cebus capucinus and conducted 12 months of study on four free-ranging groups between January 2007 and September2008. We found both sex and color vision effects. Sex: Males spent more time foraging for invertebrates on the ground. Femalesspent more time consuming embedded, colonial invertebrates, ate relatively more 'soft' sedentary invertebrates, and devotedmore of their activity budget to invertebrate foraging. Color Vision: Dichromatic monkeys had a higher capture efficiency of exposedinvertebrates and spent less time visually foraging. Trichromats ate relatively more 'hard' sedentary invertebrates. We concludethat some variation in invertebrate foraging reflects differences between the sexes that may be due to disparities in size,strength, reproductive demands or niche preferences. However, other intraspecific variation in invertebrate foraging that might bemistakenly attributed to sex differences actually reflects differences in color vision [Current Zoology 56 (3): 300-312, 2010].

Crumbs proteins stabilize the cone mosaics of photoreceptors and improve vision in zebrafish

Although the unique organization of vertebrate cone mosaics was first described long ago,both their underlying molecular basis and physiological significance are largely unknown.Here,we demonstrate that Crumbs proteins,the key regulators of epithelial apical polarity,establish the planar cellular polarity of photoreceptors in zebrafish.Via heterophilic Crb2a-Crb2b interactions,the apicobasal polarity protein Crb2b restricts the asymmetric planar distribution of Crb2a in photoreceptors.The planar polarized Crumbs proteins thus balance intercellular adhesions and tension between photoreceptors,thereby stabilizing the geometric organization of cone mosaics.Notably,loss of Crb2b in zebrafish induces a nearsightedness-like phenotype in zebrafish accompanied by an elongated eye axis and impairs zebrafish visual perception for predation.These data reveal a detailed mechanism for cone mosaic homeostasis via previously undiscovered apical-planar polarity coordination and propose a pathogenic mechanism for nearsightedness.