Initiation of feeding by four sympatric Neotropical primates (Ateles belzebuth, Lagothrix lagotricha poeppigii, Plecturocebus (Callicebus) discolor, and Pithecia aequatorialis) in Amazonian Ecuador: Relationships to photic and ecological factors

Abstract

We examined photic and ecological factors related to initiation of feeding by four sympatric primates in the rain forest of Amazonian Ecuador. With rare exceptions, morning activities of all taxa began only after the onset of nautical twilight, which occurred 47–48 min before sunrise. The larger spider and woolly monkeys, Ateles belzebuth and Lagothrix lagotricha poeppigii, left their sleeping trees before sunrise about half the time, while the smaller sakis and titi monkeys, Pithecia aequatorialis and Plecturocebus (formerly Callicebus) discolor, did not emerge until sunrise or later. None of the four taxa routinely began feeding before sunrise. Pithecia began feeding a median 2.17 h after sunrise, at least 0.8 h later than the median feeding times of the other three taxa. The early movement of Ateles and Lagothrix, and late initiation of feeding by Pithecia are consistent with temporal niche partitioning. Among most New World primate species, all males and many females, have dichromatic color vision, with only two cone photopigments, while some females are trichromats with three cone photopigments. Current evidence indicates that the dichromats have a foraging advantage in dim light, which could facilitate utilization of twilight periods and contribute to temporal niche partitioning. However, in our study, dichromatic males did not differentially exploit the dim light of twilight, and times of first feeding bouts of female Ateles and Lagothrix were similar to those of males. First feeding bouts followed a seasonal pattern, occurring latest in May-August, when ripe fruit abundance and ambient temperature were both relatively low. The most frugivorous taxon, Ateles, exhibited the greatest seasonality, initiating feeding 1.4 h later in May-August than in January-April. This pattern may imply a strategy of conserving energy when ripe fruit is scarcer, but starting earlier to compete successfully when fruit is more abundant. Lower temperatures were associated with later feeding of Ateles (by 26 min / °C) and perhaps Pithecia, but not Lagothrix or Plecturocebus. The potential for modification of temporal activity patterns and temporal niche partitioning by relatively small changes in temperature should be considered when predicting the effects of climate change.

The evolution of pair‐living, sexual monogamy, and cooperative infant care: Insights from research on wild owl monkeys, titis, sakis, and tamarins

“…The climate is hot and humid, with mean monthly temperatures of 24–27°C throughout the year (Van Belle, Fernandez‐Duque, & Di Fiore, ). Mean annual precipitation is 2,924 ± SD 267 mm (2009 to 2014) with the wettest period occurring from March through June (Snodderly et al, ). Additionally, between 2000 and 2001, one of us (MH) conducted a 16‐month field study on wild mustached tamarins ( S. mystax mystax ) at the Estación Biológica Quebrada Blanco (EBQB, 73°09’ W, 4°21’ S, about 120 m above sea level, encompassing ca.…”

Reproductive seasonality in two sympatric primates (Ateles belzebuth and Lagothrix lagotricha poeppigii) from Amazonian Ecuador

“…Although there is not a pronounced dry season, rainfall can vary dramatically between months. March through July are consistently the wettest months of the year with ≥250 mm of rain falling each month, while August and September tend to be drier, with rainfall increasing again in October, peaking in November, then drying off again for December and January (Snodderly et al, 2019). Still, there is a considerable interannual variation that muddies this pattern (Snodderly et al, 2019).…”

“…March through July are consistently the wettest months of the year with ≥250 mm of rain falling each month, while August and September tend to be drier, with rainfall increasing again in October, peaking in November, then drying off again for December and January (Snodderly et al, 2019). Still, there is a considerable interannual variation that muddies this pattern (Snodderly et al, 2019). Because of its location near the equator, photoperiod is consistent throughout the year, although the timing of sunrise may vary as much as 30 min during a biannual cycle.…”

“…Because of its location near the equator, photoperiod is consistent throughout the year, although the timing of sunrise may vary as much as 30 min during a biannual cycle. Sunrise occurs slightly earlier in May and November and slightly later in February and August (Snodderly et al, 2019). The field site hosts an intact predator community (Blake et al, 2012) as well as 10 different species of nonhuman primates (Di Fiore et al, 2017).…”

Comparative ecological and behavioral study of Macaca assamensis and M. mulatta in Shivapuri Nagarjun National Park, Nepal

“…Many studies of sympatric and non-sympatric primates have indicated that diet and space are factors affecting competition and conflict. Several studies on primate populations have shown that primates adopt various strategies for coexistence—for example, Snodderly et al ( 2019 ) reported that four sympatric species, Ateles belzebuth, Lagothrix lagotricha poeppigii, Plecturocebus discolor, and Pithecia aequatorialis , adopted temporal niche partitioning by feeding at different diurnal periods. Competitive food exclusivity in Diana monkeys ( Cercopithecus diana ) maintained resource partitioning by allowing access to fruit-rich diets through competitive exclusion of sympatric congeners (Kane and McGraw 2017 ).…”