Spatial Distribution and Exploitation of Trees Gouged by Common Marmosets (Callithrix jacchus)
alouatta-palliata; callitrichids; Exudativory; food resource distribution; GIS; group-size; home-range use; howler monkeys; Intergroup competition; japanese macaques; monkeys erythrocebus-patas; patch size; Renewable; Resource distribution; resources; social-organization; territorial defense; Zoology
Resource distribution shapes many aspects of primate behavioral ecology. Though the spatial patterning of fruits, leaves, and insects has been explored among primate foods, comparatively less is known about exudate distributions. Tree exudates are a renewable resource, provide long-term evidence of exploitation, and may be selectively exploited to manipulate spatial distribution. We assessed the spatial patterning of trees gouged by common marmosets (Callithrix jacchus) to determine if they exhibit a uniform, random, or clumped distribution. We also asked whether marmosets selectively gouge trees in home range centers, which may afford them exclusive access to exudates. We explored whether spatial or physical characteristics of trees predict how intensely gouged trees were exploited. The mean nearest neighbor distance of gouged trees was significantly closer than expected for a random distribution and Ripley's K-function showed that gouged trees were clumped across all spatial scales in our study area. Clumping may enable marmosets to reduce day and home ranges and facilitate repeated gouging of trees. Gouged trees were not closer to marmosets' home range centers than peripheries, nor were centrally located trees more intensely gouged. Increased gouging intensity was associated with larger tree circumferences, although this effect was primarily driven by interspecific differences in circumference. Although marmosets may benefit from exploiting clumped exudates, they do not concentrate gouging in areas where they are more likely to gain exclusive access. Species-specific tree characteristics such as exudate quality and/or bark properties may play a larger role in determining gouging patterns than intergroup feeding competition.
Thompson C L; Robl N J; Melo L C; Valena-Montenegro M M; Valle Y B M; de Oliveira M A B; Vinyard C J
International Journal of Primatology
2013
2013-02
Journal Article
<a href="http://doi.org/10.1007/s10764-012-9647-7" target="_blank" rel="noreferrer noopener">10.1007/s10764-012-9647-7</a>
Non-Monogamous Copulations and Potential Within-Group Mating Competition in White-Faced Saki Monkeys (Pithecia pithecia)
aggression; behavior; group-dynamics; harassment; japanese macaques; mating harassment; mating system; multimale; pair living; primate; sexual coercion; social-organization; social-organization; sperm; Zoology
Many primates display within-species variation in social organization and mating system. Individuals of these species may be confronted with both the challenges of between-group competition to exclude same-sex competitors as well as within-group competition for mating opportunities. Free-ranging white-faced saki monkeys (Pithecia pithecia) live in both male-female pairs and small multi-male, multi-female groups. Despite commonly held views that this species is monogamous, there are currently no published accounts of mating patterns in the genus Pithecia. I recorded copulations and sexual behavior from three free-ranging groups of white-faced sakis at Brownsberg Naturepark, Suriname over a period of 17 months. Groups displayed both monogamous and polygynandrous mating. Individuals in polygynandrous groups were not observed to mate more frequently with certain partners. Copulation harassment occurred in 8.6% of copulations (total N=81) and was performed by both sexes. This harassment successfully prevented ejaculation in six out of seven instances and harassment by males resulted in male-male aggression on four occasions. Two cases of female-directed sexual aggression by males were also observed, which may indicate that males use sexual coercion to influence female mating behavior. Although based on a small number of groups, these data show that white-faced sakis display variability in mating system and that this variability is not directly dictated by social organization. Furthermore, groups with promiscuous copulations exhibit behaviors indicative of within-group mating competition. Am. J. Primatol. 75:817-824, 2013. (c) 2013 Wiley Periodicals, Inc.
Thompson C L
American Journal of Primatology
2013
2013-08
Journal Article
<a href="http://doi.org/10.1002/ajp.22142" target="_blank" rel="noreferrer noopener">10.1002/ajp.22142</a>