| 1. |
- Ah-King, Malin, 1973-, et al.
(författare)
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Phylogenetic analysis of twinning in Callitrichinae
- 2000
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Ingår i: American Journal of Primatology. - 0275-2565 .- 1098-2345. ; 51:2, s. 135-146
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Tidskriftsartikel (refereegranskat)abstract
- The callitrichines are known for twinning and for a communal rearingsystem in which all or most group members help care for the offspring.The origin of twinning has been the subject of much speculation. In thisstudy predictions from earlier hypotheses are tested on the basis of twoalternative phylogenetic trees. From this analysis we infer that helpingbehavior and male care preceded the origin of twinning, and that thesetraits did not coevolve with, but might have been important prerequisitesfor twinning in callitrichines. Small body size does not necessarilyresult in twinning, although it might still have been a prerequisite forits evolution. Gum feeding was an ecological change which evolved alongwith twinning. If nutrition was a limiting factor in the number of offspringproduced, then the use of a new feeding resource could have beencrucial for the origin of twinning in callitrichines. According to one of thetwo alternative solutions inferred by the total evidence tree, and in accordancewith the morphological tree, semi-annual breeding appears inthe marmosets together with specialization in gum feeding. The fact thatgums are available for these monkeys all year may have facilitated semiannualbreeding. We suggest that the exploitation of gums as a feedingresource could have been the decisive factor in the increase of the reproductiverate by twinning and by semi-annual breeding.
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| 2. |
- Campenni, Marco, et al.
(författare)
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Exchanging Grooming, But not Tolerance and Aggression in Common Marmosets (Callithrix jacchus)
- 2015
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Ingår i: American Journal of Primatology. - : Wiley. - 0275-2565 .- 1098-2345. ; 77:2, s. 222-228
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we investigated the reciprocal exchanges of grooming, tolerance and reduced aggression in common marmosets (Callithrix jacchus), a cooperatively breeding primate whose groups are typically characterized by uniformly high genetic relatedness and high interdependency between group members. Both partner control and partner choice processes played a role in the reciprocal exchanges of grooming. In contrast, we did not find any evidence of reciprocity between grooming and tolerance over a preferred food source or between grooming and reduced aggression. Thus, reciprocity seems to play a variable role in the exchange of cooperative behaviors in marmosets. Am. J. Primatol. 77:222-228, 2015.
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| 3. |
- Laska, Matthias, 1960-, et al.
(författare)
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Taste difference thresholds for monosodium glutamate and sodium chloride in pigtail macaques (Macaca nemestrina) and spider monkeys (Ateles geoffroyi)
- 2008
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Ingår i: American Journal of Primatology. - : Wiley. - 0275-2565 .- 1098-2345. ; 70:8, s. 839-847
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to determine taste difference thresholds for monosodium glutamate (MSG) and sodium chloride (NaCl) in pigtail macaques (Macaca nemestrina) and spider monkeys (Ateles geoffroyi). Using a two-bottle preference test of brief duration, three animals of each species were presented with four different reference concentrations of 50, 100, 200, and 400 mM of a tastant and tested for their ability to discriminate these from lower concentrations of the same tastant. The just noticeable differences (JNDs), expressed as Weber ratios (ΔI/I), were found to range from 0.1 to 0.5 for MSG and 0.2 to 0.45 for NaCl in the pigtail macaques, with a significant tendency for higher Weber ratios with higher reference concentrations. In the spider monkeys, JNDs ranged from 0.15 to 0.4 for MSG and 0.1 to 0.25 for NaCl, with Weber ratios staying fairly constant across the reference concentrations tested. Thus, the JNDs were found to be generally similar in both species and to be at least as low as those found in humans for MSG and NaCl, as well as those found in spider monkeys for sucrose. The results support the assumption that both pigtail macaques and spider monkeys may use differences in perceived intensity of MSG and NaCl as a criterion for food selection. © 2008 Wiley-Liss, Inc.
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| 4. |
- Laska, Matthias, 1960-, et al.
(författare)
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Which senses play a role in nonhuman primate food selection ? A comparison between squirrel monkeys and spider monkeys
- 2007
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Ingår i: American Journal of Primatology. - : Wiley. - 0275-2565 .- 1098-2345. ; 69:3, s. 282-294
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Tidskriftsartikel (refereegranskat)abstract
- In order to optimize foraging efficiency and avoid toxicosis, animals must be able to detect, discriminate, and learn about the predictive signals of potential food. Primates are typically regarded as animals that rely mainly on their highly developed visual systems, and little is known about the role that the other senses may play in food selection. It was therefore the aim of the present study to assess which senses are involved in the evaluation of food by two species of New World primates: the squirrel monkey and the spider monkey. To this end, six animals per species were repeatedly presented with both familiar and novel food items, and their behavior was videotaped and analyzed. To obtain a further indication of the relative importance of visual and chemosensory cues, the animals were also presented with familiar food items that were experimentally modified in color, odor, or both color and odor. The results demonstrate that squirrel monkeys and spider monkeys use olfactory, gustatory, and tactile cues in addition to visual information to evaluate novel food, whereas they mainly inspect familiar food items visually prior to consumption. Our findings also show that in both species the use of nonvisual cues decreased rapidly with repeated presentations of novel food, suggesting a fast multimodal learning process. Further, the two species clearly differ in their relative use of nonvisual cues when evaluating novel or modified food, with spider monkeys relying more on olfactory cues than squirrel monkeys, and squirrel monkeys relying more on tactile cues compared to spider monkeys.
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| 5. |
- Malukiewicz, Joanna, et al.
(författare)
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Application of PE-RADSeq to the study of genomic diversity and divergence of two Brazilian marmoset species (Callithrix jacchus and C-penicillata)
- 2017
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Ingår i: American Journal of Primatology. - : WILEY. - 0275-2565 .- 1098-2345. ; 79:2
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Tidskriftsartikel (refereegranskat)abstract
- Callithrix jacchus and C. penicillata are among the smallest anthropoid primates, are highly specialized tree gougers, and largely occupy Brazil's most extreme, semi-arid biomes. However, the underlying genomic factors that underpin the evolution of these species and their unique traits are under-investigated. Additionally, exotic populations of these two species are widely established throughout Brazil and hybridize with threatened native congers. Thus, both genomic and conservation factors call for a better understanding of C. jacchus and C. penicillata evolution. Here, we applied PE-RADseq to characterize genomic variation in these two species, using six C. jacchus and seven C. penicillata individuals. We identified an average of 7,463 and 5,180 SNPs/individual in C. penicillata and C. jacchus, respectively, and also found 1,395 variable sites that were represented in both species. C. penicillata showed overall higher levels of genetic diversity than C. jacchus at the variable sites present in both species. Additionally, among these variable sites, 106 showed relative interspecific divergence levels that were significantly higher than the genome-wide average. We further compared relative and absolute divergence for C. penicillata and C. jacchus between RAD loci associated with the 106 significantly diverged variable sites and all other RAD loci present in both species. The former RAD loci set showed significantly elevated relative and absolute divergence measures in comparison to the latter set. This convergence suggests that C. jacchus and C. penicillata may have diverged under a scenario of gene flow under secondary contact. Here, we demonstrate that RADseq is an efficient method to simultaneously discover and genotype a large number of markers and validate the utility of RADseq for examining Callithrix evolution.
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| 6. |
- Sanchez-Solano, Karem G., et al.
(författare)
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Visual detection and fruit selection by the mantled howler monkey (Alouatta palliata)
- 2020
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Ingår i: American Journal of Primatology. - : WILEY. - 0275-2565 .- 1098-2345. ; 82:10
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Tidskriftsartikel (refereegranskat)abstract
- Howler monkeys (platyrrhini) have evolved routine trichromatic color vision independently from catarrhines, which presents an opportunity to test hypotheses concerning the adaptive value of distinguishing reddish from greenish hues. A longstanding hypothesis posits that trichromacy aids in the efficient detection of reddish-ripe fruits, which could be an advantage for the detection of the nutritional content of the fruit, such as sugars. In the present study, we assessed fruit visual conspicuity and selection based on color and sucrose content by wild mantled howler monkeys (Alouatta palliata) on Agaltepec Island, Mexico. We used colorimetry to classify dietary fruits as cryptic (greenish) or conspicuous (reddish) against their background leaves. Species-specific color models indicate that trichromatic howler monkeys should be more efficient in discriminating the conspicuous ripe fruits from leaves compared to detecting cryptic ripe fruits from leaves. We found howler monkeys consume more cryptic fruits compared to conspicuous fruits, and that they consume more unripe fruits than ripe fruits. The consumption (acceptance) of fruit was independent of sucrose content, and thus this disaccharide may not play an essential role in mantled howler food selection. Our findings suggest that routine trichromatic color vision may aid in the detection and discrimination of conspicuously colored fruits, but that the final decision whether to accept or reject a fruit probably involves the use of other senses in addition to vision.
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| 7. |
- Staedele, Veronika, et al.
(författare)
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The complex Y-chromosomal history of gorillas
- 2022
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Ingår i: American Journal of Primatology. - : John Wiley & Sons. - 0275-2565 .- 1098-2345. ; 84:3
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Tidskriftsartikel (refereegranskat)abstract
- Studies of the evolutionary relationships among gorilla populations using autosomal and mitochondrial sequences suggest that male-mediated gene flow may have been important in the past, but data on the Y-chromosomal relationships among the gorilla subspecies are limited. Here, we genotyped blood and noninvasively collected fecal samples from 12 captives and 257 wild male gorillas of known origin representing all four subspecies (Gorilla gorilla gorilla, G. g. diehli, G. beringei beringei, and G. b. graueri) at 10 Y-linked microsatellite loci resulting in 102 unique Y-haplotypes for 224 individuals. We found that western lowland gorilla (G. g. gorilla) haplotypes were consistently more diverse than any other subspecies for all measures of diversity and comprised several genetically distinct groups. However, these did not correspond to geographical proximity and some closely related haplotypes were found several hundred kilometers apart. Similarly, our broad sampling of eastern gorillas revealed that mountain (G. b. beringei) and Grauer's (G. b. graueri) gorilla Y-chromosomal haplotypes did not form distinct clusters. These observations suggest structure in the ancestral population with subsequent mixing of differentiated haplotypes by male dispersal for western lowland gorillas, and postisolation migration or incomplete lineage sorting due to short divergence times for eastern gorillas.
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| 8. |
- van Dijk, Eva S. J., et al.
(författare)
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Hand preference predicts behavioral responses to threats in Barbary macaques
- 2023
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Ingår i: American Journal of Primatology. - : WILEY. - 0275-2565 .- 1098-2345. ; 85:7
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Tidskriftsartikel (refereegranskat)abstract
- The structure and functioning of the brain are lateralized-the right hemisphere processes unexpected stimuli and controls spontaneous behavior, while the left deals with familiar stimuli and routine responses. Hemispheric dominance, the predisposition of an individual using one hemisphere over the other, may lead to behavioral differences; particularly, an individual may be programed to act in a certain way concerning hemispheric dominance. Hand preference is a robust estimator of hemispheric dominance in primates, as each hemisphere controls the opposing side of the body. Studies have found links between hand preference and the exhibition of behaviors in contexts such as exploring and manipulating objects. However, little is known whether hand preference predicts behavioral variations in other ecologically relevant contexts like predation. We investigated the relationship between hand preference and behavioral responses to two types of predator models in captive Barbary macaques (Macaca sylvanus) (n = 22). Besides, a nonpredator novel object was included as control. We found 91% of the macaques to be lateralized with no group-level bias. A higher rate of tension and focus (behavioral response) behavior was found in predator contexts than in the novel object condition. Unlike their right-hand counterparts, individuals with a strong left-hand preference elicited frequent focus and tension behavior toward the predator models. Additionally, the behavioral response varied with predator type. We also found an interaction effect between hand preference and predator type. Our study suggests that hand preference can reliably predict behavioral variations in the context of potential predation. While these results are consistent with lateralized brain function, indicating lateralization a neural mechanism of behavioral variation, the interaction effect between hand preference and predator type elucidates the importance of context-specificity when investigating laterality noninvasively. Future research on other nonhuman primates using the current framework may provide insights into the evolution of laterality and underlying behavioral predispositions.
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| 9. |
- Qureshi, Adil Masoud, et al.
(författare)
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Self-phasing of quadrifilar helix antenna by relative axial displacement of bifilars
- 2015
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Ingår i: Microwave and Optical Technology Letters. - : Wiley. - 1098-2760 .- 0895-2477. ; 57:2, s. 430-432
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Tidskriftsartikel (refereegranskat)abstract
- Self-phasing can be achieved in a quadrifilar helix antenna (QHA) by displacing one of the bifilars along the axis of the helix, yielding a circularly polarized cardioid shaped pattern. Impedance bandwidth of 10% (2105-2345 MHz) has been achieved with Front to back ratio greater than 10 dB.
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