Do pied tamarins increase scent-marking in response to urban noise?

AbstractSounds produced by human activities are often loud and may mask acoustic signals used by other species for communication. To circumvent this, some animals use various strategies, including shifting modality completely or complementing acoustic information by using additional modalities to communicate. Here we used pied tamarins (Saguinus bicolor) as models to explore whether shifts in communication modalities occur under increased anthropogenic noise or deploy them complementarily. We predicted that in circumstances where noise could impede acoustic communication the study animals would exhibit more scent-marking behaviour (i.e. olfactory communication) while reducing the emission of long calls (i.e. acoustic communication). We collected information on vocal and scent-marking behaviour in nine groups of wild pied tamarins in urban forests in Manaus, Amazonian Brazil. We found that scent marking occurrence increased with noise amplitude, though long call numbers did not change. Thus, our results do not suggest a complete shift between channels but complementation of information, where scent marking may compensate for the impacts of anthropogenic noise on the acoustic channel. This is an interesting result from a conservation perspective as pied tamarins may be capable of coping with city noise to communicate with conspecifics, a key tenet of species survival.Highlights Some species shift communication channels in response to anthropogenic noise.Pied tamarins do not reduce the number of long calls in response to anthropogenic noise, but the occurrence of scent markings increases with noise levels.Pied tamarins do not shift between channels, but scent marking may be used to complement information between channels.Key Words: animal communicationurban soundscapemultimodalityolfactoryAmazonSaguinus bicolor ACKNOWLEDGMENTSWe thank Caio Fábio Pereira, and colleagues from the Projeto Sauim-de-Coleira and Amazonian Mammals Research Group (AMRG) for logistical and field assistance. We also thank Fiene Steinbrecher for kindly sharing data on pied tamarin call amplitude; and the CENBAM/PPBio support during development of this manuscript.DISCLOSURE STATEMENTNo potential conflict of interest was reported by the authors.ETHICAL STANDARDThe Project was approved by the Ethical Committee of the InstitutoNacional de Pesquisas da Amazônia (SEI.01280.009002018–58).SISBIO/MMA (Ministry of Environment) granted us the necessary licenses to capture, anesthetize, manipulate, and mark the subjects (N. 60347–1). Appropriate licenses were obtained to access municipal and state parks and military areas.AUTHOR CONTRIBUTIONT.V. Sobroza, A.A. Barnett, M. Gordo and J.C. Dunn originally formulated the research topic. T.V. Sobroza raised funds, collected data, performed statistical analyses and wrote the original draft. A.A. Barnett, M. Gordo, and J.C. Dunn supervised. A.A. Barnett and J.C. Dunn checked the English. All authors contributed to the writing and reviewingAdditional informationFundingThis study was supported by Casella Solutions, International Primatology Society (s/n 2018), Idea Wild (s/n 2018), National Geographic under grant EC-419 R-18, Primate Action Fund/Margot Marsh Biodiversity Foundation under grant SMA-CCO-G0000000111, and Rufford Foundation under grant 24762-1. T.V. Sobroza received a FAPEAM scholarship (062.01758/2018).