Determinants of vocal usage in the genus Chlorocebus

Schad, Lukas

dc.contributor.advisor	Fischer, Julia Prof. Dr.
dc.contributor.author	Schad, Lukas
dc.date.accessioned	2023-08-04T10:46:27Z
dc.date.available	2023-08-11T00:50:12Z
dc.date.issued	2023-08-04
dc.identifier.uri	http://resolver.sub.uni-goettingen.de/purl?ediss-11858/14817
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-10041
dc.format.extent	151	de
dc.language.iso	deu	de
dc.rights	Attribution-NonCommercial-NoDerivatives 4.0 International	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/4.0/	*
dc.subject.ddc	570	de
dc.title	Determinants of vocal usage in the genus Chlorocebus	de
dc.type	doctoralThesis	de
dc.contributor.referee	Fischer, Julia Prof. Dr.
dc.date.examination	2022-12-06	de
dc.description.abstracteng	The vocal communication of non-human primates has been the center of extensive research efforts that aimed to advance our understanding of the evolution of vocal communication and human speech. The alarm call system of the genus Chlorocebus has received particular attention after it was discovered that vervet monkeys (C. pygerythrus) produce distinct vocalizations in response to their major predators that appeared to designate the presence of particular threats, which was interpreted as a potential sign of semantic communication. While the ensuing search for evolutionary precursors to the human language faculty in non-human primates has inspired a productive field of research, basic ethological questions concerned with the biological function of vocal signals that determines their structure and usage have received less attention. This thesis examines variation of vocal usage in the alarm call system of members of the genus Chlorocebus and aims to contribute to our understanding of the mechanisms that guide call usage and enable signals to exert their effects on receivers. Further it is examined what inter-individual variation in call usage can teach us about the potential function of vocal signals. To investigate the mechanisms that guide predator type categorization and the production of specific alarm call types by signalers, an experiment was conducted with West African green monkeys (C. sabaeus) and South African vervet monkeys (C. pygerythrus). Monkeys were exposed to novel aerial and terrestrial threats, to test if alarm calling behavior is sensitive to positional cues and experience. While the experiment was not able to answer said question since vervet monkeys did not produce any calls in response to the presented stimuli, it demonstrates variation in call usage among different populations which may relate to species differences or population specific differences in anthropogenic disturbance and predation pressure. To advance our understanding of the inter-individual variation in call usage, a 24-month observational study was conducted on vervet monkeys. The usage of “terrestrial threat barks” or “leopard alarms” by adult male vervet monkeys was quantified and analyzed with regard to male competitive ability, tenure, group specific variation in the degree of male-male competition and the impact of the mating season. Results indicate that high ranking males were more likely to produce barks than lower ranking individuals and that the mating season increases the daily frequency of observed barking events. The findings imply that call usage is gated by male competitive ability or motivation and suggests that barks may function as conventional or quality handicap signals indicating male motivation and potentially stamina. This finding and the frequent usage of barks in contexts other than land predator events show that context specificity in this call type has previously been overestimated and that barks may fulfill a dual function of alarm call and signal of individual quality. In conclusion, vocal usage in the genus Chlorocebus shows considerable population specific and inter-individual variation. This implies that individual experience and social factors may play a central role in guiding individual vocal behavior. The variation in call usage further suggests that signals that have hitherto been primarily viewed as alarm calls may serve more than one function. Potential mechanisms that would render signals effective at exerting their effects on receivers are suggested. Finally, the potential selective forces shaping call structure and usage are discussed and an impact of natural and intra-sexual selection is proposed.	de
dc.contributor.coReferee	Gail, Alexander Prof. Dr.
dc.subject.eng	Alarm calls	de
dc.subject.eng	primate loud calls	de
dc.subject.eng	intra sexual selection	de
dc.subject.eng	vocal communication	de
dc.subject.eng	vervet monkey	de
dc.subject.eng	Chlorocebus pygerythrus	de
dc.subject.eng	drone	de
dc.subject.eng	remotely piloted aircraft system	de
dc.subject.eng	RPAS	de
dc.subject.eng	remote sensing	de
dc.subject.eng	UAV	de
dc.subject.eng	unmanned aerial vehicle	de
dc.identifier.urn	urn:nbn:de:gbv:7-ediss-14817-4
dc.affiliation.institute	Biologische Fakultät für Biologie und Psychologie	de
dc.subject.gokfull	Biologie (PPN619462639)	de
dc.description.embargoed	2023-08-11	de
dc.identifier.ppn	1854426974
dc.identifier.orcid	0000-0001-5825-2145	de
dc.notes.confirmationsent	Confirmation sent 2023-08-04T11:15:01	de

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