The effect of habitat acoustics on common marmoset vocal signal transmission

Abstract

Noisy acoustic environments present several challenges for the evolution of acoustic communication systems. Among the most significant is the need to limit degradation of spectro-temporal signal structure in order to maintain communicative efficacy. This can be achieved by selecting for several potentially complementary processes. Selection can act on behavioral mechanisms permitting signalers to control the timing and occurrence of signal production to avoid acoustic interference. Likewise, the signal itself may be the target of selection, biasing the evolution of its structure to comprise acoustic features that avoid interference from ambient noise or degrade minimally in the habitat. Here, we address the latter topic for common marmoset (Callithrix jacchus) long-distance contact vocalizations, known as phee calls. Our aim was to test whether this vocalization is specifically adapted for transmission in a species-typical forest habitat, the Atlantic forests of northeastern Brazil. We combined seasonal analyses of ambient habitat acoustics with experiments in which pure tones, clicks, and vocalizations were broadcast and rerecorded at different distances to characterize signal degradation in the habitat. Ambient sound was analyzed from intervals throughout the day and over rainy and dry seasons, showing temporal regularities across varied timescales. Broadcast experiment results indicated that the tone and click stimuli showed the typically inverse relationship between frequency and signaling efficacy. Although marmoset phee calls degraded over distance with marked predictability compared with artificial sounds, they did not otherwise appear to be specially designed for increased transmission efficacy or minimal interference in this habitat. We discuss these data in the context of other similar studies and evidence of potential behavioral mechanisms for avoiding acoustic interference in order to maintain effective vocal communication in common marmosets.

Behavioural strategies associated with using an ephemeral roosting resource in Spix's disc-winged bat

“…These calls were emitted by bats during flight, which suggests that the calls are important in establishing or maintaining contact with conspecifics during nightly foraging and roost reconnaissance trips. While the fast flight behaviour of T. tricolor means that tracking individuals and their associated patterns of call emission is particularly difficult, we can gain insight into the behavioural function of these calls by examining their temporal and spectral structure (Kime, Turner, & Ryan, 2000;Morrill, Thomas, Schiel, Souto, & Miller, 2013). One critical factor in understanding the communication signals of any species is the environment in which the animal lives (Bradbury & Vehrencamp, 2000;Ryan & Brenowitz, 1985).…”

Marmosets: A Neuroscientific Model of Human Social Behavior

“…Their proclivity to produce vocal signals at high rates contrasts with many Old World primates, including rhesus monkeys, and is thought to be an adaptation to the dense vegetation in the forest habitats marmosets have lived throughout their evolutionary history (Morrill et al, 2013; Rylands et al, 2009). Limits imposed on visual signaling from vegetation may have necessitated the use of vocal signals for maintaining social contact with conspecifics.…”

Responses of primate frontal cortex neurons during natural vocal communication

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