Presentation on theme: "Primate Interactions: Polyspecific Associations. Definition Dispersing individuals Groups of two or more species Permanent or moderate association Distribution."— Presentation transcript:
Definition Dispersing individuals Groups of two or more species Permanent or moderate association Distribution Rare among prosimians, apes New and Old World Monkeys- common
Considerations…. Is it random? Is it mutually beneficial? Does it only benefit one party but not the other (neutral = commensalism)? Does it benefit one party and influence the other party negatively? (Parasitism)
Benefits Foraging –Avoid previously used areas –Increased insect capture rate –Share knowledge of food sources Predation –Detection faster, earlier –Avoidance (larger groups)
Examples Dispersing anecdotes Guenons (Africa) New World Primates- Manu, Peru (see Ch 8- Terborgh reading in coursepak).
Cebus and Saimiri Capuchin (Cebus) Squirrel monkey (Saimiri)
Type of Association Positive for Squirrel monkey, slightly negative for Capuchin Moderate association, seasonal To understand benefits... Who leads? What happens when species is alone? How is contact initiated?
Leadership Not necessarily who is in front –Large group size (squirrel monkeys) –Circumstances (type of activit or food (Table 8.1 in article, See graph next page)
Graph from Table 8.1 (article) - values are percents of both Cebus categories
Leadership? Capuchins more influential regarding group movements But Squirrel monkeys more actively try to maintain relationship with groups.
What happens when alone? Squirrel monkeys change behavior significantly more than capuchines when alone. –Travel further, faster –Seemed to actively seek other capuchin groups –Influence each other’s travel when together (graph next page).
Who initiates contact? Squirrel monkeys seem to actively seek out Capuchin groups. Capuchin don’t make any vocal sounds when squirrel monkeys come and go. Squirrel monkeys are with capuchins more than capuchins with squirrel monkeys (see table 8.3).
Benefits-Predation Capuchins have excellent predator detection skills (vocal, Vigilance) Squirrel monkeys are more intensive foragers, don’t pay attention as much (also smaller in size). Group size might benefit both.
Benefits- Foraging FRUIT –Squirrel monkeys learn where fruit trees are (but don’t leave?) –Exploit fruit/nuts of Scheelea Insect feeding –Improve insect flushing (not really…)
Summary Squirrel monkeys benefit… –Predator warning –Access to Scheelea nuts –Learn fruit source location (esp.when scarce) Capuchin –Negative- increased travel –Lose fruit perhaps –Possible selfish herd
Forest differences?? Less overlap in diet between species Less likely to use the other for information Lower predation? Presence of other species (mangabeys, baboons, red colobus) Lower density of animals More overlap in diet, use each other for information More predation? Lower density of animals KibaleKakamanga
Benefits and costs Possible predator detection at Kakamanga (larger groups at Kibale) Red-tails gain knowledge of food sources from blue monkeys at Kakamanga. BUT red-tails do get chased. Both species travel further when in association.