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Vigilance in a Cooperatively Breeding Primate.

Stojan-Dolar M, Heymann EW - Int. J. Primatol. (2010)

Bottom Line: As vigilance decreased in proximity of conspecifics and heterospecifics when feeding, and in larger mixed-species groups when resting, we conclude that the predominant function of vigilance in mustached tamarins is predator related.We found no evidence that mustached tamarins monitor group mates to avoid food stealing or aggression.The effect of heterospecifics on individual vigilance suggests that collective vigilance might have been an important incentive in the evolution of tamarin mixed-species groups.

View Article: PubMed Central - PubMed

ABSTRACT
Collective vigilance is considered a major advantage of group living in animals. We investigated vigilance behavior in wild mustached tamarins (Saguinus mystax), small, arboreal, cooperatively breeding New World primates that form stable mixed-species groups with saddleback tamarins (Saguinus fuscicollis). We aimed 1) to investigate whether vigilance patterns change according to individual activity and 2) to examine whether there is a social component of vigilance in their cooperative and nonaggressive society. We studied 11 factors that may influence vigilance and used this data to interpret the possible functions of vigilance. We observed 44 individuals in 3 mixed-species and 2 single-species groups of 2 populations that differed in population density and home range sizes. Vigilance changed greatly when individuals were engaged in different activities and individual vigilance was affected by different sets of factors depending on the activity. As vigilance decreased in proximity of conspecifics and heterospecifics when feeding, and in larger mixed-species groups when resting, we conclude that the predominant function of vigilance in mustached tamarins is predator related. However, the absence of the group size effect in very large single-species groups suggests that it may also function to maintain group cohesion. In the population with higher density and smaller home ranges individuals also increased their vigilance in home range overlap areas. We found no evidence that mustached tamarins monitor group mates to avoid food stealing or aggression. The effect of heterospecifics on individual vigilance suggests that collective vigilance might have been an important incentive in the evolution of tamarin mixed-species groups.

No MeSH data available.


Related in: MedlinePlus

Factors affecting vigilance during (○) resting, (◊) feeding at EBQB, (♦) feeding at PI, (□) passive grooming, and () active grooming. Graphs represent the effects of (a) number of conspecifics ≤2 m; (b) distance to conspecifics; (c) distance to heterospecifics; (d) total single-species group size; (e) total mixed-species group size; (f) age; (g) height of the focal individual; and (h) vegetation density. Statistically significant (p < 0.05) effects are shown in black. Error bars represent SE. *Statistically significant at p < 0.05 (Bonferroni pairwise comparisons).
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Fig4: Factors affecting vigilance during (○) resting, (◊) feeding at EBQB, (♦) feeding at PI, (□) passive grooming, and () active grooming. Graphs represent the effects of (a) number of conspecifics ≤2 m; (b) distance to conspecifics; (c) distance to heterospecifics; (d) total single-species group size; (e) total mixed-species group size; (f) age; (g) height of the focal individual; and (h) vegetation density. Statistically significant (p < 0.05) effects are shown in black. Error bars represent SE. *Statistically significant at p < 0.05 (Bonferroni pairwise comparisons).

Mentions: Vigilance was influenced by different sets of factors during different activities (Table III; Figs. 4 and 5). During resting, vigilance decreased with total MSG size, increased with infant carrying, and first decreased, then increased with height. During feeding, vigilance decreased with the presence of conspecific neighbors and increased with distance to conspecifics and distance to heterospecifics. There were also differences between the sites. At PI, but not at EBQB, vigilance during feeding was higher in home range overlap areas for both sexes. At EBQB, but not at PI, vigilance during feeding increased with height and males were more vigilant than females. Higher male vigilance could imply social vigilance due to increased intrasexual competition as a result of a higher male/female ratio at EBQB. In this case, males at EBQB would not decrease their vigilance in the proximity of neighbors. This was not the case: both males and females were less vigilant if they had neighbors ≤2 m (GLMM, males: F(3,212) = 6.4, p < 0.001, females: F(3,154) = 5.1, p < 0.001) and if nearest neighbor was closer (males: F(4,210) = 4.4, p < 0.001, females: F(3,141) = 2.9, p < 0.05). Vigilance during passive grooming was influenced only by vegetation density and was highest at places with medium cover density. During active grooming vigilance was not influenced by any of the factors included in the analysis.Table III


Vigilance in a Cooperatively Breeding Primate.

Stojan-Dolar M, Heymann EW - Int. J. Primatol. (2010)

Factors affecting vigilance during (○) resting, (◊) feeding at EBQB, (♦) feeding at PI, (□) passive grooming, and () active grooming. Graphs represent the effects of (a) number of conspecifics ≤2 m; (b) distance to conspecifics; (c) distance to heterospecifics; (d) total single-species group size; (e) total mixed-species group size; (f) age; (g) height of the focal individual; and (h) vegetation density. Statistically significant (p < 0.05) effects are shown in black. Error bars represent SE. *Statistically significant at p < 0.05 (Bonferroni pairwise comparisons).
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Related In: Results  -  Collection

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Fig4: Factors affecting vigilance during (○) resting, (◊) feeding at EBQB, (♦) feeding at PI, (□) passive grooming, and () active grooming. Graphs represent the effects of (a) number of conspecifics ≤2 m; (b) distance to conspecifics; (c) distance to heterospecifics; (d) total single-species group size; (e) total mixed-species group size; (f) age; (g) height of the focal individual; and (h) vegetation density. Statistically significant (p < 0.05) effects are shown in black. Error bars represent SE. *Statistically significant at p < 0.05 (Bonferroni pairwise comparisons).
Mentions: Vigilance was influenced by different sets of factors during different activities (Table III; Figs. 4 and 5). During resting, vigilance decreased with total MSG size, increased with infant carrying, and first decreased, then increased with height. During feeding, vigilance decreased with the presence of conspecific neighbors and increased with distance to conspecifics and distance to heterospecifics. There were also differences between the sites. At PI, but not at EBQB, vigilance during feeding was higher in home range overlap areas for both sexes. At EBQB, but not at PI, vigilance during feeding increased with height and males were more vigilant than females. Higher male vigilance could imply social vigilance due to increased intrasexual competition as a result of a higher male/female ratio at EBQB. In this case, males at EBQB would not decrease their vigilance in the proximity of neighbors. This was not the case: both males and females were less vigilant if they had neighbors ≤2 m (GLMM, males: F(3,212) = 6.4, p < 0.001, females: F(3,154) = 5.1, p < 0.001) and if nearest neighbor was closer (males: F(4,210) = 4.4, p < 0.001, females: F(3,141) = 2.9, p < 0.05). Vigilance during passive grooming was influenced only by vegetation density and was highest at places with medium cover density. During active grooming vigilance was not influenced by any of the factors included in the analysis.Table III

Bottom Line: As vigilance decreased in proximity of conspecifics and heterospecifics when feeding, and in larger mixed-species groups when resting, we conclude that the predominant function of vigilance in mustached tamarins is predator related.We found no evidence that mustached tamarins monitor group mates to avoid food stealing or aggression.The effect of heterospecifics on individual vigilance suggests that collective vigilance might have been an important incentive in the evolution of tamarin mixed-species groups.

View Article: PubMed Central - PubMed

ABSTRACT
Collective vigilance is considered a major advantage of group living in animals. We investigated vigilance behavior in wild mustached tamarins (Saguinus mystax), small, arboreal, cooperatively breeding New World primates that form stable mixed-species groups with saddleback tamarins (Saguinus fuscicollis). We aimed 1) to investigate whether vigilance patterns change according to individual activity and 2) to examine whether there is a social component of vigilance in their cooperative and nonaggressive society. We studied 11 factors that may influence vigilance and used this data to interpret the possible functions of vigilance. We observed 44 individuals in 3 mixed-species and 2 single-species groups of 2 populations that differed in population density and home range sizes. Vigilance changed greatly when individuals were engaged in different activities and individual vigilance was affected by different sets of factors depending on the activity. As vigilance decreased in proximity of conspecifics and heterospecifics when feeding, and in larger mixed-species groups when resting, we conclude that the predominant function of vigilance in mustached tamarins is predator related. However, the absence of the group size effect in very large single-species groups suggests that it may also function to maintain group cohesion. In the population with higher density and smaller home ranges individuals also increased their vigilance in home range overlap areas. We found no evidence that mustached tamarins monitor group mates to avoid food stealing or aggression. The effect of heterospecifics on individual vigilance suggests that collective vigilance might have been an important incentive in the evolution of tamarin mixed-species groups.

No MeSH data available.


Related in: MedlinePlus