Polyspecific associations are an important component of Callimico goeldii behavior and ecology. On average, Callimico goeldii was found in proximity to or in vocal contact with Saguinus troops (S. fuscicollis and S. labiatus) during 53% of all time intervals sampled. Polyspecific associations varied considerably between seasons, however, with association rates peaking during the wet-season month of February (89%) and declining in the dry season, with the lowest rate (13%) in July. The primary benefits of associations appear to be an increased use of the lower and middle canopy, and an increase in feeding behaviors during the wet season. Thus, Callimico goeldii appear to benefit most from associations during the wet season when fruits are its principal food source. Fruits are eaten more in the forest canopy than in the understory; thus, an increase in height use likely permits an increase in the fruit resources on which Callimico goeldii can forage and feed. In addition, Saguinus groups, with their smaller home ranges, are likely to be more knowledgeable than Callimico goeldii about the location and abundance of ripe fruits in their home ranges. Thus, Callimico goeldii may parasitize Saguinus for their fruit knowledge by following them through their ranges. In the dry season, limited dietary overlap between Callimico goeldii and Saguinus groups is likely to make associations less beneficial for Callimico goeldii as they adopt different foraging and ranging strategies.

Tamarins are reported to live in small multimale-multifemale groups characterized by a single breeding female. Here we present information on the composition and genetic relatedness of individuals in 12 wild-trapped groups of Weddell's saddleback tamarins (Saguinus weddelli) from northern Bolivia to determine if groups are best described as nuclear or extended families suggesting social monogamy or whether groups contain several unrelated same sex adults indicative of social polyandry/polygyny. Mean group size was 6.25 including an average of 2.16 adult males (range 1-4) and 2.08 adult females (1-3). No group contained only one adult male and one adult female and 25% of groups contained two parous females. We estimated the genetic relatedness among individuals using 13 polymorphic microsatellite markers. Across the population, mean relatedness was low and not significantly different among adult males versus among adult females, suggesting that both sexes disperse from their natal groups. Adults of both sexes also tended to have close same-sex adult relatives within their groups; relatedness among adult females of the same group averaged 0.31 and among adult males was 0.26. This suggests that tamarins of one or both sexes sometimes delay dispersal and remain as adults in their natal group or that emigration of same-sexed relatives into the same group may be common. Finally, parentage analyses indicated that, whereas the parents of juveniles generally were present in the group, this was not always the case. Based on these data, published reports of the presence of multiple breeding males and occasionally multiple breeding females in the same group, and the fact that less than 10% of groups in the wild contain a single adult male-adult female pair, we argue that social polyandry best characterizes the composition of tamarin groups and that monogamy is not a common mating pattern in Saguinus weddelli or other tamarin species.

Since Darwin (1859), scientists have been puzzled by how behaviors that impose fitness costs on helpers while benefiting their competitors could evolve through natural selection. Hamilton's (1964) theory of inclusive fitness provided an explanation by showing how cooperative behaviors could be adaptive if directed at closely related kin. Recent studies, however, have begun to question whether kin selection is sufficient to explain cooperative behavior in some species (Bergm€ uller, Johnstone, Russell, & Bshary, 2007). Many researchers have instead emphasized the importance of direct fitness benefits for helpers in the evolution of cooperative breeding systems.Furthermore, individuals can vary in who, when, and how much they help, and the factors that affect this variation are poorly understood (Cockburn, 1998;Heinsohn, 2004). Cooperative breeders thus provide excellent models for the study of evolutionary theories of cooperation and conflict (Cant, 2012). K E Y W O R D Sallocare, cooperative breeding, kin selection, marmosets, tamarins

We studied the diet, habitat use, and ranging behavior of 1 group of Callimico goeldii (callimicos) over 12 mo in northwestern Bolivia. The group's diet was comprised of fungi (39%), fruits (31%), arthropods (14%), exudates (14%), and other matter (2%). Callimicos concentrated their ranging activities in secondary forest (50%), primary forest with dense understory (30%), and bamboo (17%) habitats. The group's total home range was 114 ha; on average they used 38.4 ha/ mo and had a day range of 925 m. Monthly average day ranges-but not monthly home ranges-increased as frugivory declined, suggesting that subjects foraged on fungi and exudates by rechecking resources within a core area, making their day ranges longer than during months when they concentrated on fruit resources. The callimicos formed polyspecific associations with tamarins (Saguinus labiatus and S. fuscicollis) during 81% of observations. Day ranges increased in months with higher association rates which appears to result from the callimicos using a broader set of habitats when with tamarins than when alone. The ranging pattern of callimicos appears to be influenced primarily by 3 factors: their seasonal shift in diet requires that they forage in a variety of habitats across the year; their depletion of resources causes them to shift their core area over time; and their lack of territorial behavior eliminates the need to patrol boundaries as part of their daily movement. As a result, callimicos differ from many other callitrichids in their low ratio of day range length to home range size.Keywords activity . callitrichids . day range . diet . height use . home range . polyspecific associations Int

Though ≥22 species of Primates consume fungi, most do so at low rates, comprising <5% of their feeding time. Goeldi's monkeys (Callimico goeldii), spend up to 29% of their feeding time year-round consuming fungal sporocarps, the fruiting bodies of fungi. We provide comprehensive data on the nutritional characteristics of 4 species of fungi consumed by Callimico goeldii (Ascopolyporus polyporoides, Ascopolyporus polychrous, Auricularia auricula, and Auricularia delicata). The composition of the fungi is similar to that of other fungi: predominantly fiber (66.2-83.0% dry matter) with small amounts of sugar (2.0-5.6% dry matter) and crude fat (0.9-1.6% dry matter). Though the crude protein content is substantial (5.5-13.4% dry matter), much of the nitrogen in the fungi is not likely to be available to Callimico goeldii because it is associated with indigestible food components or is in nonprotein form. The mineral content of the fungi are within the normal range for fungi generally and the calcium-to-phosphorus ratio is low (0.07-0.25). Fungi appear to be a low-quality food resource for Callimico goeldii and may contribute to their relatively large home ranges and low population density compared to other Callitrichinae. Research on the ability of Callimico goeldii to digest fungi is needed to understand fully the 324 Hanson, Hall, Porter, and Lintzenich nutritional value of fungi to them. We discuss adaptations Callimico goeldii may have for improving their ability to obtain nutrients from fungi and potential ecological correlates of mycophagy.

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Callimico goeldii, Saguinus fuscicollis, and S. labiatus are sympatric in northern Bolivia and differ from each other in patterns of spatial and structural use of their environment. C. goeldii has a home range five times larger than that of mixed-species troops of S. fuscicollis and S. labiatus. The larger overlapping home range of C. goeldii allows it to move among Saguinus troops, giving it access to a wide range of different microhabitats. All three species use the most common microhabitat in the area, primary forest with dense understory, more than any other microhabitat type. C. goeldii habitat use varies by season, with bamboo and Heliconia microhabitats used more during the dry season. Each species shows preferences for different height classes: C. goeldii is found almost exclusively in the understory, S. fuscicollis uses the understory and middle canopy, and S. labiatus is found mostly in the middle canopy. These height class preferences are reflected in each species' locomotor styles, with C. goeldii showing the highest rates of vertical clinging and leaping, and S. labiatus showing the highest rates of branch-to-branch leaping and quadrupedal movement. The results suggest that C. goeldii may be restricted to forests with dense understory and a mosaic of other microhabitats. Furthermore, C. goeldii does not appear to use its tegulae for large branch foraging, but rather for vertical clinging and leaping between small vertical supports.