Small Neotropical primates promote the natural regeneration of anthropogenically disturbed areas.

Increasingly large proportions of tropical forests are anthropogenically disturbed. Where natural regeneration is possible at all, it requires the input of plant seeds through seed dispersal from the forest matrix. Zoochorous seed dispersal - the major seed dispersal mode for woody plants in tropical forests - is particularly important for natural regeneration. In this study, covering a period of more than 20 years, we show that small New World primates, the tamarins Saguinus mystax and Leontocebus nigrifrons, increase their use of an anthropogenically disturbed area over time and disperse seeds from primary forest tree species into this area. Through monitoring the fate of seeds and through parentage analyses of seedlings of the legume Parkia panurensis from the disturbed area and candidate parents from the primary forest matrix, we show that tamarin seed dispersal is effective and contributes to the natural regeneration of the disturbed area.

Territorial Polemics: A Response to Roberts.

Our recent paper Lledo-Ferrer et al. (International Journal of Primatology 32: 974-991, 2011) questioned the classic view of territoriality and chemical communication in wild callitrichids, saddleback tamarins (Saguinus fuscicollis). We suggested that rather than defending a territory or resources, chemical communication was more likely to be a way of exchanging reproductive information between groups. Roberts (International Journal of Primatology 33, 2012). challenged this interpretation, considering that the results could more parsimoniously be interpreted as fulfilling a resource defense strategy. This response is intended to clarify some aspects of the debate and to suggest how further research could shed new light on the present polemics.

The Equivocal Relationship Between Territoriality and Scent Marking in Wild Saddleback Tamarins (Saguinus fuscicollis).

Researchers have often assumed that scent marking serves a territorial function in callitrichines, although some controversy exists. To fulfill such a function, scent marks should 1) prevent intrusions, 2) ensure access to feeding resources, 3) enable avoidance of intergroup encounters, or 4) play an important role in the aggressive encounters between groups. We studied 13 saddleback tamarins (Saguinus fuscicollis) belonging to 3 free-ranging groups, which formed mixed-species troops with moustached tamarins (S. mystax) in the Amazonian rain forest of Peru. None of the predictions were confirmed. The tamarins used a border-marking strategy, marking more on the periphery of their territory. However, feeding trees in overlap and encounter areas received more scent marking but were still visited by neighboring groups. Intergroup encounters occurred more often than expected, and scent-marking frequency was not higher during them than when no other group was present. It appears that instead of defending a territory in the classic sense, the tamarins are optimizing signal transmission by depositing their scents where the probability of detection by neighbors is higher. Saddleback tamarins may use shared areas of their home ranges to exchange information with neighboring groups, perhaps regarding reproductive opportunities. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10764-011-9516-9) contains supplementary material, which is available to authorized users.

Reproductive failure, possible maternal infanticide, and cannibalism in wild moustached tamarins, Saguinus mystax.

Maternal infanticide in wild non-human primates has only been reported twice. In this paper, we report a possible new case of infanticide and cannibalism within a series of four successive reproductive failures in wild moustached tamarins, Saguinus mystax. Necropsy and genetic analyses of the corpses enabled us to rule out any pathology, and to determine paternity. The mother was seen biting and then eating the head of its own infant during a period when another female was pregnant and gave birth just 1 month later. Before that, the perpetrator had given birth to twins three times successfully when four to five adult and subadult males were present in the group. Although we do not know for certain that the infant was alive when the mother started biting it, our field observations preceding the event suggest it probably was. The possible infanticide case and the two cases of births and early death of the infants occurred while only two to three adult males were present in the group. This could be the second case of maternal infanticide reported in the genus Saguinus and the similar circumstances suggest a common pattern. We discuss these events in the light of the different functional explanations of infanticide and conclude that parental manipulation was the most likely: the mother could have terminated the investment in offspring that had low chances of survival in a group with low availability of helpers.

Can overmarking be considered as a means of chemical mate guarding in a wild callitrichid?

Mate guarding is a male strategy to monopolize matings and thus to ensure paternity. Since in callitrichids female reproductive status is advertised by scent marks, one may expect mate guarding by chemical means. We addressed this question during an episode of consortship observed in a polyandrous trio of wild saddleback tamarins (Saguinus fuscicollis). During consortship, the consort male was the only one to allomark the female. Scent marking frequency decreased for all individuals, although the consort male marked more than the other male during consortship, while there was no difference in the previous period. During consortship, almost 50% of female scents were overmarked by the consort, and more than 56% of the consort's scent marks were employed to overmark the female's scents. Therefore, the other male had limited access to female scent marks. Mate guarding may thus have a chemical component in tamarins, and olfactory communication may play an important role in mating competition.