Predation affects alarm call usage in female Diana monkeys (Cercopithecus diana diana)

Abstract

Diana monkeys produce acoustically distinct calls to a number of external events, including different types of predators. In a previous study, we found population-wide differences in male alarm call production in Taï Forest, Ivory Coast, and on Tiwai Island, Sierra Leone, mostly likely originating from differences in predator experience. In Taï Forest, leopards (Panthera pardus) are common but on Tiwai Island they have been absent for decades, while the predation pressure from crowned eagles (Stephanoaetus coronatus) has been similar. To further evaluate the impact of predator experience, we here analyse the vocal behaviour of female Diana monkeys in both habitats. Female Diana monkeys produce predatorspecific alarm calls, alert calls and contact calls in response to predators, suggesting that their calls serve in a broader range of functions compared to males. Results showed that females produced the same call types at both sites, despite the differences in predator fauna. Regarding call usage, leopard alarm calls were extremely rare on Tiwai Island, but not in Taï Forest, whereas we found no differences in eagle alarm call production. When comparing response latencies, Tiwai females were slower to respond to both predators compared to Taï females. Finally, we found no habitat-specific acoustic differences in the alert and predator-specific alarm calls, but significant differences in frequency-based parameters of contact calls. Overall, our results suggest that ontogenetic experience can affect primate vocal behaviour in both usage and acoustic structure but that the way in which particular call types are affected may be closely linked to function.

Social familiarity affects Diana monkey ( Cercopithecus diana diana ) alarm call responses in habitat-specific ways

“…Playback stimuli were obtained by simulating the presence of a crowned eagle or a leopard by playing back their typical vocalizations ( N leopard growls =3; N eagle shrieks =3) to different males. We then used these responses as playback stimuli to elicit alarm call responses from our target subjects [ 6 , 31 , 32 ]. At both sites, playbacks could be from a familiar male, defined as an alarm call response recorded from a neighbouring group’s male of the same habitat, or an unfamiliar male.…”

“…At the level of individual calls, we analysed the presence of frequency transitions at the onset of calls [ 32 ] as well as several other frequency-related and temporal parameters. For this purpose, we used the PRAAT DSP package (settings: time step: 0.03 s; expected F0 frequency range: 500–2000 Hz), with an automatic logger in an output file to extract the following variables: (a) mean fundamental frequency (mean_F0; Hz), (b) maximum and minimum fundamental frequency (max_F0 and min_F0; Hz), (c) range of fundamental frequency (range_F0; Hz), (d) fundamental frequency at the beginning and end of a call (start_F0, end_F0; Hz).…”

“…In Taï Forest, Ivory Coast, males consistently produce all three alarm call types in event-specific ways (eagle, leopard and general disturbance), whereas on Tiwai Island, Sierra Leone—a habitat characterized by long-term absence of leopards [ 31 ]—males only distinguish between eagles on the one hand and leopards and general disturbances on the other hand. Females also differ in their vocal responses to leopard-related events in habitat-specific ways (in terms of call rates, latencies but not acoustic structure [ 32 ]). Crowned eagles are present in both habitats and male alarm call responses to them are similar across both habitats.…”

A guild classification system proposed for anuran advertisement calls

“…The main functions of intra-specific acoustic communication are attraction, detection and selection of mates, territoriality, and / or exchange of other information (e.g. warning or release; Bee and Gerhardt 2002;Ballentine et al 2004;Wollenberg and Harvey 2010;Stephan and Zuberbühler 2014).…”

Non-specific alarm calls trigger mobbing behavior in Hainan gibbons (Nomascus hainanus)

“…Predator-induced songs were identical to normal songs in the call note repertoire, for example, Lar gibbons ( Hylobates lar ) generate significant, context-dependent acoustic variations of their main social call, which potentially allows recipients to make inferences about events experienced by the caller 8 9 10 11 . Particular call types may be closely linked to function 12 .…”