Fallback foods (FBFs) are hypothesized to shape the ecology, morphology, and behavior of primates... more Fallback foods (FBFs) are hypothesized to shape the ecology, morphology, and behavior of primates, including hominins. Identifying FBFs is therefore critical for revealing past and present foraging adaptations. Recent research suggests invertebrates act as seasonal FBFs for many primate species and human populations. Yet, studies measuring the consumption of invertebrates relative to ecological variation are widely lacking. We address this gap by examining food abundance and entomophagy by primates in a seasonal forest. We study foraging behavior of white-faced capuchins (Cebus capucinus)-a species renowned for its intelligence and propensity for extractive foraging-along with the abundance of invertebrates, dietary ripe fruits, pith, and bromeliads. Consumption events and processing time are recorded during focal animal samples. We determine abundance of vegetative foods through phenological and density records. Invertebrates are collected in malaise, pan, and terrestrial traps; ca...
Ecological variation strongly influences female reproductive endocrinology, frequently resulting ... more Ecological variation strongly influences female reproductive endocrinology, frequently resulting in seasonal patterns linked to energetic constraints. Such energetic constraints may similarly affect males, but research has emphasized social factors, while largely ignoring ecological influences on male reproduction. We examine the effects of both ecological variation (food availability, rainfall season, temperature) and social factors (reproductive season, male age/rank) on fecal glucocorticoids (fGC, N=1342 from 24 males between July 2006-2010) and testosterone (fT, N=1056 from 19 males between July 2008-2010) in white-faced capuchins living in a seasonal environment. Repeated measures GLMMs indicate that male fGC was significantly predicted by fruit biomass (F=6.048, p=0.015), rainfall (F=9.381, p=0.002), male age/rank (F=26.698, p=0.002), and reproductive season (F=12.359, p<0.001), but not temperature (F=0.294, p=0.588). Analysis of residuals indicate that fGC levels were high...
The capacity for cone-mediated color vision varies among nocturnal primates. Some species are col... more The capacity for cone-mediated color vision varies among nocturnal primates. Some species are colorblind, having lost the functionality of their short-wavelength-sensitive-1 (SWS1) opsin pigment gene. In other species, such as the aye-aye (Daubentonia madagascariensis), the SWS1 gene remains intact. Recent studies focused on aye-ayes indicate that this gene has been maintained by natural selection and that the pigment has a peak sensitivity (lambda(max)) of 406 nm, which is -20 nm closer to the ultraviolet region of the spectrum than in most primates. The functional significance behind the retention and unusual lambda(max) of this opsin pigment is unknown, and it is perplexing given that all mammals are presumed to be colorblind in the dark. Here we comment on this puzzle and discuss recent findings on the color vision intensity thresholds of terrestrial vertebrates with comparable optics to aye-ayes. We draw attention to the twilight activities of aye-ayes and report that twilight is enriched in short-wavelength (bluish) light. We also show that the intensity of twilight and full moonlight is probably sufficient to support cone-mediated color vision. We speculate that the intact SWS1 opsin pigment gene of aye-ayes is a crepuscular adaptation and we report on the blueness of potential visual targets, such as scent marks and the brilliant blue arils of Ravenala madagascariensis.
Understanding the signals used by plants to attract seed disperses is a pervasive quest in evolut... more Understanding the signals used by plants to attract seed disperses is a pervasive quest in evolutionary and sensory biology. Fruit size, colour, and odour variation have long been discussed in the controversial context of dispersal syndromes targeting olfactory-oriented versus visually-oriented foragers. Trade-offs in signal investment could impose important physiological constraints on plants, yet have been largely ignored. Here, we measure the reflectance and volatile organic compounds of a community of Malagasy plants and our results indicate that extant plant signals may represent a trade-off between olfactory and chromatic signals. Blue pigments are the most visually-effective - blue is a colour that is visually salient to all known seed dispersing animals within the study system. Additionally, plants with blue-reflecting fruits are less odiferous than plants that reflect primarily in other regions of the colour spectrum.
ABSTRACT Opsins provide an excellent model system for studying evolutionary interconnections at g... more ABSTRACT Opsins provide an excellent model system for studying evolutionary interconnections at genetic, phenotypic and behavioural levels. Primates have evolved a unique ability for trichromatic colour vision from a dichromatic mammalian ancestor. This was accomplished via allelic differentiation (e.g. most New World monkeys) or gene duplication (e.g. Old World primates) of the middle to long-wavelength sensitive (M/LWS) opsin gene. However, questions remain, Ó Springer-Verlag Berlin Heidelberg 2012 225 regarding the behavioural adaptations of primate trichromacy. Allelic differenti-ation of the M/LWS opsins results in extensive colour vision variability in New World monkeys, where trichromats and dichromats are found in the same breeding population, enabling us to directly compare visual performances among different colour vision phenotypes. Thus, New World monkeys can serve as an excellent model to understand and evaluate the adaptive significance of primate trichromacy in a behavioural context. In this chapter, we summarise recent findings on colour vision evolution in vertebrates, with special emphasis on primates, and introduce our genetic and behavioural study on primate colour vision polymorphism and adaptation.
New World monkeys exhibit prominent colour vision variation due to allelic polymorphism of the lo... more New World monkeys exhibit prominent colour vision variation due to allelic polymorphism of the long-to-middle wavelength (L/M) opsin gene. The known spectral variation of L/M opsins in primates is broadly determined by amino acid composition at three sites: 180, 277 and 285 (the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;three-sites&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; rule). However, two L/M opsin alleles found in the black-handed spider monkeys (Ateles geoffroyi) are known exceptions, presumably due to novel mutations. The spectral separation of the two L/M photopigments is 1.5 times greater than expected based on the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;three-sites&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; rule. Yet the consequence of this for the visual ecology of the species is unknown, as is the evolutionary mechanism by which spectral shift was achieved. In this study, we first examine L/M opsins of two other Atelinae species, the long-haired spider monkeys (A. belzebuth) and the common woolly monkeys (Lagothrix lagotricha). By a series of site-directed mutagenesis, we show that a mutation Y213D (tyrosine to aspartic acid at site 213) in the ancestral opsin of the two alleles enabled N294K, which occurred in one allele of the ateline ancestor and increased the spectral separation between the two alleles. Second, by modelling the chromaticity of dietary fruits and background leaves in a natural habitat of spider monkeys, we demonstrate that chromatic discrimination of fruit from leaves is significantly enhanced by these mutations. This evolutionary renovation of L/M opsin polymorphism in atelines illustrates a previously unappreciated dynamism of opsin genes in shaping primate colour vision.
Primate colour vision has intrigued scientists for many decades and will likely continue to do so... more Primate colour vision has intrigued scientists for many decades and will likely continue to do so for the foreseeable future. Primates are the most visually adapted order of mammals and a considerable proportion of their large brain size is devoted to processing visual ...
Fallback foods (FBFs) are hypothesized to shape the ecology, morphology, and behavior of primates... more Fallback foods (FBFs) are hypothesized to shape the ecology, morphology, and behavior of primates, including hominins. Identifying FBFs is therefore critical for revealing past and present foraging adaptations. Recent research suggests invertebrates act as seasonal FBFs for many primate species and human populations. Yet, studies measuring the consumption of invertebrates relative to ecological variation are widely lacking. We address this gap by examining food abundance and entomophagy by primates in a seasonal forest. We study foraging behavior of white-faced capuchins (Cebus capucinus)-a species renowned for its intelligence and propensity for extractive foraging-along with the abundance of invertebrates, dietary ripe fruits, pith, and bromeliads. Consumption events and processing time are recorded during focal animal samples. We determine abundance of vegetative foods through phenological and density records. Invertebrates are collected in malaise, pan, and terrestrial traps; ca...
Ecological variation strongly influences female reproductive endocrinology, frequently resulting ... more Ecological variation strongly influences female reproductive endocrinology, frequently resulting in seasonal patterns linked to energetic constraints. Such energetic constraints may similarly affect males, but research has emphasized social factors, while largely ignoring ecological influences on male reproduction. We examine the effects of both ecological variation (food availability, rainfall season, temperature) and social factors (reproductive season, male age/rank) on fecal glucocorticoids (fGC, N=1342 from 24 males between July 2006-2010) and testosterone (fT, N=1056 from 19 males between July 2008-2010) in white-faced capuchins living in a seasonal environment. Repeated measures GLMMs indicate that male fGC was significantly predicted by fruit biomass (F=6.048, p=0.015), rainfall (F=9.381, p=0.002), male age/rank (F=26.698, p=0.002), and reproductive season (F=12.359, p<0.001), but not temperature (F=0.294, p=0.588). Analysis of residuals indicate that fGC levels were high...
The capacity for cone-mediated color vision varies among nocturnal primates. Some species are col... more The capacity for cone-mediated color vision varies among nocturnal primates. Some species are colorblind, having lost the functionality of their short-wavelength-sensitive-1 (SWS1) opsin pigment gene. In other species, such as the aye-aye (Daubentonia madagascariensis), the SWS1 gene remains intact. Recent studies focused on aye-ayes indicate that this gene has been maintained by natural selection and that the pigment has a peak sensitivity (lambda(max)) of 406 nm, which is -20 nm closer to the ultraviolet region of the spectrum than in most primates. The functional significance behind the retention and unusual lambda(max) of this opsin pigment is unknown, and it is perplexing given that all mammals are presumed to be colorblind in the dark. Here we comment on this puzzle and discuss recent findings on the color vision intensity thresholds of terrestrial vertebrates with comparable optics to aye-ayes. We draw attention to the twilight activities of aye-ayes and report that twilight is enriched in short-wavelength (bluish) light. We also show that the intensity of twilight and full moonlight is probably sufficient to support cone-mediated color vision. We speculate that the intact SWS1 opsin pigment gene of aye-ayes is a crepuscular adaptation and we report on the blueness of potential visual targets, such as scent marks and the brilliant blue arils of Ravenala madagascariensis.
Understanding the signals used by plants to attract seed disperses is a pervasive quest in evolut... more Understanding the signals used by plants to attract seed disperses is a pervasive quest in evolutionary and sensory biology. Fruit size, colour, and odour variation have long been discussed in the controversial context of dispersal syndromes targeting olfactory-oriented versus visually-oriented foragers. Trade-offs in signal investment could impose important physiological constraints on plants, yet have been largely ignored. Here, we measure the reflectance and volatile organic compounds of a community of Malagasy plants and our results indicate that extant plant signals may represent a trade-off between olfactory and chromatic signals. Blue pigments are the most visually-effective - blue is a colour that is visually salient to all known seed dispersing animals within the study system. Additionally, plants with blue-reflecting fruits are less odiferous than plants that reflect primarily in other regions of the colour spectrum.
ABSTRACT Opsins provide an excellent model system for studying evolutionary interconnections at g... more ABSTRACT Opsins provide an excellent model system for studying evolutionary interconnections at genetic, phenotypic and behavioural levels. Primates have evolved a unique ability for trichromatic colour vision from a dichromatic mammalian ancestor. This was accomplished via allelic differentiation (e.g. most New World monkeys) or gene duplication (e.g. Old World primates) of the middle to long-wavelength sensitive (M/LWS) opsin gene. However, questions remain, Ó Springer-Verlag Berlin Heidelberg 2012 225 regarding the behavioural adaptations of primate trichromacy. Allelic differenti-ation of the M/LWS opsins results in extensive colour vision variability in New World monkeys, where trichromats and dichromats are found in the same breeding population, enabling us to directly compare visual performances among different colour vision phenotypes. Thus, New World monkeys can serve as an excellent model to understand and evaluate the adaptive significance of primate trichromacy in a behavioural context. In this chapter, we summarise recent findings on colour vision evolution in vertebrates, with special emphasis on primates, and introduce our genetic and behavioural study on primate colour vision polymorphism and adaptation.
New World monkeys exhibit prominent colour vision variation due to allelic polymorphism of the lo... more New World monkeys exhibit prominent colour vision variation due to allelic polymorphism of the long-to-middle wavelength (L/M) opsin gene. The known spectral variation of L/M opsins in primates is broadly determined by amino acid composition at three sites: 180, 277 and 285 (the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;three-sites&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; rule). However, two L/M opsin alleles found in the black-handed spider monkeys (Ateles geoffroyi) are known exceptions, presumably due to novel mutations. The spectral separation of the two L/M photopigments is 1.5 times greater than expected based on the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;three-sites&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; rule. Yet the consequence of this for the visual ecology of the species is unknown, as is the evolutionary mechanism by which spectral shift was achieved. In this study, we first examine L/M opsins of two other Atelinae species, the long-haired spider monkeys (A. belzebuth) and the common woolly monkeys (Lagothrix lagotricha). By a series of site-directed mutagenesis, we show that a mutation Y213D (tyrosine to aspartic acid at site 213) in the ancestral opsin of the two alleles enabled N294K, which occurred in one allele of the ateline ancestor and increased the spectral separation between the two alleles. Second, by modelling the chromaticity of dietary fruits and background leaves in a natural habitat of spider monkeys, we demonstrate that chromatic discrimination of fruit from leaves is significantly enhanced by these mutations. This evolutionary renovation of L/M opsin polymorphism in atelines illustrates a previously unappreciated dynamism of opsin genes in shaping primate colour vision.
Primate colour vision has intrigued scientists for many decades and will likely continue to do so... more Primate colour vision has intrigued scientists for many decades and will likely continue to do so for the foreseeable future. Primates are the most visually adapted order of mammals and a considerable proportion of their large brain size is devoted to processing visual ...
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