RESUMO

Worldwide urban expansion and deforestation have caused a rapid decline of non-human primates in recent decades. Yet, little is known to what extent these animals can tolerate anthropogenic noise arising from roadway traffic and human presence in their habitat. We studied six family groups of titis residing at increasing distances from a busy highway, in a park promoting ecotourism near Santa Cruz de la Sierra, Bolivia. We mapped group movements, sampled the titis' behavior, collected fecal samples from each study group and conducted experiments in which we used a mannequin simulating a human intrusion in their home range. We hypothesized that groups of titi monkeys exposed to higher levels of anthropogenic noise and human presence would react weakly to the mannequin and show higher concentrations of fecal cortisol compared with groups in least perturbed areas. Sound pressure measurements and systematic monitoring of soundscape inside the titis' home ranges confirmed the presence of a noise gradient, best characterized by the root-mean-square (RMS) and median amplitude (M) acoustic indices; importantly, both anthropogenic noise and human presence co-varied. Study groups resided in small, overlapping home ranges and they spent most of their time resting and preferentially used the lower forest stratum for traveling and the higher levels for foraging. Focal sampling analysis revealed that the time spent moving by adult pairs was inversely correlated with noise, the behavioral change occurring within a gradient of minimum sound pressures ranging from 44 dB(A) to 52 dB(A). Validated enzyme-immunoassays of fecal samples however detected surprisingly low cortisol concentrations, unrelated to the changes observed in the RMS and M indices. Finally, titis' response to the mannequin varied according to our expectation, with alarm calling being greater in distant groups relative to highway. Our study thus indicates reduced alarm calling through habituation to human presence and suggests a titis' resilience to anthropogenic noise with little evidence of physiological stress.

RESUMO

Cheracebus is a new genus of New World primate of the family Pitheciidae, subfamily Callicebinae. Until recently, Cheracebus was classified as the torquatus species group of the genus Callicebus. The genus Cheracebus has six species: C. lucifer, C. lugens, C. regulus, C. medemi, C. torquatus, and C. purinus, which are all endemic to the Amazon biome. Before the present study, there had been no conclusive interpretation of the phylogenetic relationships among most of the Cheracebus species. The present study tests the monophyly of the genus and investigates the relationships among the different Cheracebus species, based on DNA sequencing of 16 mitochondrial and nuclear markers. The phylogenetic analyses were based on Maximum Likelihood, Bayesian Inference, and multispecies coalescent approaches. The divergence times and genetic distances between the Cheracebus taxa were also estimated. The analyses confirmed the monophyly of the genus and a well-supported topology, with the following arrangement: ((C. torquatus, C. lugens), (C. lucifer (C. purinus, C. regulus))). A well-differentiated clade was also identified within part of the geographic range of C. lugens, which warrants further investigation to confirm its taxonomic status.

Assuntos

RESUMO

Titi monkeys (family Pitheciidae) are Neotropical primates highly diversified in morphology, ecology and genetics, with a wide geographic distribution, including the Amazon, Atlantic Forest, Cerrado, Pantanal and Caatinga. This diversity, together with knowledge gaps, generates uncertainties in titi monkey taxonomy and distribution. An example is Plecturocebus baptista, with only 14 occurrence records and an ill-defined distribution based on untested geographical barriers. Here, we report the occurrence of this species at a new locality outside its known range, across the Paraná-Urariá River, which was considered a distributional limit for the species. The new record implies an overlap of P. baptista with the range of P. hoffmannsi. We document the sighting of an apparent hybrid animal. Our observations suggest that i) the distribution of P. baptista needs to be reviewed, and ii) the evolutionary relationships between P. baptista and P. hoffmannsi may be more complex than previously assumed. Since both species share contiguous areas of potential hybridization, we question whether the two species arose via allopatric speciation.(AU)

Macacos zogue-zogue (família Pitheciidae) são primatas neotropicais altamente diversificados em morfologia, ecologia e genética, com distribuição geográfica abrangente, incluindo a Floresta Amazônica, Mata Atlântica, Cerrado, Pantanal e a Caatinga. Essa diversificação, juntamente com lacunas de conhecimento, gera incertezas na taxonomia e distribuição das espécies. Um exemplo é Plecturocebus baptista, com apenas 14 registros de ocorrência e distribuição indefinida, baseada em barreiras geográficas não testadas. Aqui nós relatamos a ocorrência da espécie em uma nova localidade, fora de sua área conhecida de distribuição, que transpõe uma suposta barreira geográfica, o Rio Paraná-Urariá. O novo registro de P. baptista se sobrepõe à distribuição de P. hoffmannsi e, neste contexto, observamos um indivíduo aparentemente híbrido entre as duas espécies. Nossas observações sugerem que i) a distribuição de P. baptista necessita ser revisada, e ii) a relação evolutiva entre P. baptista e P. hoffmannsi pode ser mais complexa do que se pensava. Como ambas espécies compartilham áreas contínuas de potencial hibridização, questionamos se as duas espécies resultaram de especiação alopátrica.(AU)

Assuntos

RESUMO

Titi monkeys (family Pitheciidae) are Neotropical primates highly diversified in morphology, ecology and genetics, with a wide geographic distribution, including the Amazon, Atlantic Forest, Cerrado, Pantanal and Caatinga. This diversity, together with knowledge gaps, generates uncertainties in titi monkey taxonomy and distribution. An example is Plecturocebus baptista, with only 14 occurrence records and an ill-defined distribution based on untested geographical barriers. Here, we report the occurrence of this species at a new locality outside its known range, across the Paraná-Urariá River, which was considered a distributional limit for the species. The new record implies an overlap of P. baptista with the range of P. hoffmannsi. We document the sighting of an apparent hybrid animal. Our observations suggest that i) the distribution of P. baptista needs to be reviewed, and ii) the evolutionary relationships between P. baptista and P. hoffmannsi may be more complex than previously assumed. Since both species share contiguous areas of potential hybridization, we question whether the two species arose via allopatric speciation. (AU)

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Primates employ many strategies to deal with the costs of reproduction. While income breeders exploit the food available in their environment during lactation, the most costly phase of reproduction, capital breeders tend to store energy for use in the period. We analyzed the relationship between resource availability and lactation in Callicebus coimbrai (n = 2 groups) and Callicebus nigrifrons (n = 2 groups) in four Brazilian Atlantic forest remnants, to assess their breeding strategy. We recorded the occurrence of births and breastfeeding events to assess birth seasonality and lactation period and length while monitoring monthly fruit availability. We recorded 11 births (five for C. coimbrai, and six for C. nigrifrons), all restricted to the end of the lean season and the beginning of the rich season. Lactation coincided with periods of increased fruit availability. We suggest that the breeding pattern of Callicebus coimbrai and C. nigrifrons is compatible with an income-based breeding strategy.

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RESUMO

The predation of army ants (Eciton rapax) was recorded during an observational study of the feeding behavior of a group of titi monkeys (Plecturocebus toppini) in an urban fragment of forest in Acre, Brazil. During one observed event, the group's adult female used its tail to retrieve ants, a type of behavior not observed previously in this genus. All incidents of on-forest floor foraging occurred during the dry season, when fruit was least abundant in the forest, while on other occasions, the ants were captured from tree branches and leaves. The observation of predation and ground-level foraging recorded in this study reinforce the adaptive capacity of P. toppini for survival in fragmented forests, and this was also the first record of the predation of army ants by this titi species.

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