title: Parturition Signaling by Visual Cues in Female Marmosets (Callithrix jacchus).
abstract: New World monkeys have polymorphic color vision, in which all males and some females are dichromats, while most females are trichromats. There is little consensus about which selective pressures fashioned primate color vision, although detection of food, mates and predators has been hypothesized. Behavioral evidence shows that males from different species of Neotropical primates seem to perceive the timing of female conception and gestation, although, no signals fulfilling this function have been identified. Therefore, we used visual models to test the hypothesis that female marmosets show chromatic and/or achromatic cues that may indicate the time of parturition for male and female conspecifics. By recording the reflectance spectra of female marmosets' (Callithrix jacchus) sexual skin, and running chromatic and achromatic discrimination models, we found that both variables fluctuate during the weeks that precede and succeed parturition, forming "U" and inverted "U" patterns for chromatic and achromatic contrast, respectively. We suggest that variation in skin chroma and luminance might be used by female helpers and dominant females to identify the timing of birth, while achromatic variations may be used as clues by potential fathers to identify pregnancy stage in females and prepare for paternal burdens as well as to detect oestrus in the early post-partum period.
authors.affiliation: Laboratory of Sensory Ecology, Department of Physiology, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Laboratory of Behavioral Endocrinology, Department of Physiology, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Laboratory for the Advanced Study of Primates, Department of Physiology, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Laís Alves Antonio
authors.initials: LA
authors.lastname: Moreira
authors.affiliation: Laboratory of Neuroscience and Behavior, Department of Physiological Sciences, University of Brasília, Brasília, DF, Brazil.
authors.forename: Danilo Gustavo Rodrigues
authors.initials: DG
authors.lastname: de Oliveira
authors.affiliation: Laboratory of Behavioral Endocrinology, Department of Physiology, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Laboratory for the Advanced Study of Primates, Department of Physiology, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Maria Bernardete Cordeiro
authors.initials: MB
authors.lastname: de Sousa
authors.affiliation: Laboratory of Sensory Ecology, Department of Physiology, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Laboratory for the Advanced Study of Primates, Department of Physiology, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Daniel Marques Almeida
authors.initials: DM
authors.lastname: Pessoa
mesh_terms: D000818:Animals; D002144:Callithrix; D055253:Color Vision / Q000502:physiology*; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D023421:Models, Animal; D036801:Parturition / Q000502:physiology*; D011247:Pregnancy; D015398:Signal Transduction / Q000502:physiology*; D012880:Skin Pigmentation / Q000502:physiology; D013997:Time Factors