Conspecific vocalisations modulate the circadian activity rhythm of marmosets

Abstract

Conspecific vocalisations have an important ecological role for marmosets and likely modulate the circadian timing system. However, the effect of this specific cue on circadian activity rhythm (CAR) has not been evaluated. To analyse the synchroniser effect of conspecific vocalisations on CAR in marmosets, the motor activity of five isolated adult males was continuously recorded in rooms with constant dim light (~2 lx) and attenuated sound. All animals presented positive masking, four presented relative coordination and three presented temporary entrainment associated with the daily pattern of vocalisations from animals kept outdoors, similarly to previous studies that assessed social cues. Furthermore, most animals displayed a shortened circadian period in response to conspecific vocalisation pulses that were reproduced daily for 30 days under total darkness. This is evidence that a non-photic cue with ecological significance can modulate the CAR, reinforcing the role of conspecific vocalisation as an important zeitgeber for marmosets.

Keywords:

• circadian rhythms
• social cues
• social entrainment
• masking
• diurnal primate
• non-photic cues

Acknowledgements

We would like to thank Aline S. Belísio and Gutemberg Pereira, who helped in the daily care of the animals; Cristiano Simões, who provided the vocalisations recorded from marmosets at the Primatology Colony and a great assistance in the study with marmosets vocalisations; Ruthnaldo R.M. Lima, who provided the speaker for vocalisations playback; Breno T. Carneiro, who helped with designing the figures presentation for this manuscript; Rafael Medeiros Araujo, for the help with the recording of conspecific vocalisations recording; Flávio Coutinho, Edinólia Câmara, Antônio Barbosa, Geniberto dos Santos, Luis do Nascimento, José Rubens and Márcio dos Santos for the animal care at the Primatology Colony of UFRN; and the esteemed Professors Alexandre A.L. Menezes, Luiz Menna-Barreto, John F. Araujo and Horacio de la Iglesia, for important suggestions during the writing of this manuscript. We would also like to thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Universidade Federal do Rio Grande do Norte for financial support.

Funding

This work was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Universidade Federal do Rio Grande do Norte (Brazil).