Geographic variation in the echolocation calls of the endemic Cape horseshoe bat, Rhinolophus capensis (Chiroptera: Rhinolophidae)

 

Show simple item record

dc.contributor.advisor Jacobs, David S en_ZA
dc.contributor.author Odendaal, Lizelle Janine en_ZA
dc.date.accessioned 2014-10-30T13:53:52Z
dc.date.available 2014-10-30T13:53:52Z
dc.date.issued 2009 en_ZA
dc.identifier.citation Odendaal, L. 2009. Geographic variation in the echolocation calls of the endemic Cape horseshoe bat, Rhinolophus capensis (Chiroptera: Rhinolophidae). University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/8976
dc.description Includes bibliographical references (leaves 63-84). en_ZA
dc.description.abstract Several intrinsic (body size) and extrinsic (foraging ecology and communication) factors are suggested to influence call frequency divergence in high duty-cycle bats. Investigating these factors within the framework of established hypotheses would contribute to understanding evolutionary changes leading to speciation in bats. Here, acoustic divergence between populations of the endemic Cape horseshoe bat, Rhinolophus capensis was investigated at both inter- and intraspecific levels. No previous study has investigated geographic variation in echolocation calls of R. capensis. Body size, wing morphology and skull parameters associated with diet and echolocation call production and reception, were compared between populations. Adult R. capensis were sampled at three sites: De Hoop situated in the centre of the species distribution in the Fynbos biome; Steenkampskraal and Table Farm were ecotone populations situated in the western and eastern limits of the distribution, respectively. Interspecific analysis revealed that the two ecotone populations deviated slightly from the allometric relationship between body size and peak frequency for the African clade. In fact, the expected inverse relationship between body size and peak frequency was not evident across populations. Ecotone populations had significantly larger mean body sizes than the population at De Hoop (10.28 ± 1.08 g; 84.60 ± 0.82 kHz). However, one population in the ecotone had the highest frequency (Table Farm: 13.88 ± 0.87 g; 85.84 ± 0.73 kHz) while the other had the lowest (Steenkampskraal: 13.15 ± 0.95 g; 80.66 ± 0.50 kHz). Several hypotheses were considered to explain the patterns of echolocation and morphological variation observed. The larger body size of the ecotone populations may be explained by James' Rule or it may be an adaptation to the intrinsic habitat heterogeneity of ecotones as it affords these bats a greater niche width and possibly larger home ranges to access spatially separated resources. On the other hand, neither climatic (humidity hypothesis), habitat (foraging habitat hypothesis) nor dietary differences (prey detection hypothesis between populations were responsible for the observed peak frequency differences between populations. Nasal chamber area was the best predictor of peak frequency and there was no relationship between the area of the nasal chamber and body size. Thus, selection may have acted directly on peak frequency altering skull parameters directly involved in echolocation independently of body size. Within each population, females were larger and used higher frequencies than males, which implies a potential social role of peak frequency for R. capensis. Observed differences in peak frequency may be because R. capensis interacts with separate rhinolophid species at either end of its distribution (Steenkampskraal: R. swinnyi; Table Farm: R. darlingi) in addition to R. clivasus, which results in the evolution of local dialects to facilitate intraspecific communication. These local dialects, possibly brought about by differences in local ambient noise characteristics (e.g. chorusing insects), could be maintained via cultural transmission. However, the role of gene flow for the evolution of these local dialects between populations cannot be discounted without adequate genetic analyses. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Zoology en_ZA
dc.title Geographic variation in the echolocation calls of the endemic Cape horseshoe bat, Rhinolophus capensis (Chiroptera: Rhinolophidae) en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Biological Sciences en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Odendaal, L. J. (2009). <i>Geographic variation in the echolocation calls of the endemic Cape horseshoe bat, Rhinolophus capensis (Chiroptera: Rhinolophidae)</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/8976 en_ZA
dc.identifier.chicagocitation Odendaal, Lizelle Janine. <i>"Geographic variation in the echolocation calls of the endemic Cape horseshoe bat, Rhinolophus capensis (Chiroptera: Rhinolophidae)."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2009. http://hdl.handle.net/11427/8976 en_ZA
dc.identifier.vancouvercitation Odendaal LJ. Geographic variation in the echolocation calls of the endemic Cape horseshoe bat, Rhinolophus capensis (Chiroptera: Rhinolophidae). [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2009 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/8976 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Odendaal, Lizelle Janine AB - Several intrinsic (body size) and extrinsic (foraging ecology and communication) factors are suggested to influence call frequency divergence in high duty-cycle bats. Investigating these factors within the framework of established hypotheses would contribute to understanding evolutionary changes leading to speciation in bats. Here, acoustic divergence between populations of the endemic Cape horseshoe bat, Rhinolophus capensis was investigated at both inter- and intraspecific levels. No previous study has investigated geographic variation in echolocation calls of R. capensis. Body size, wing morphology and skull parameters associated with diet and echolocation call production and reception, were compared between populations. Adult R. capensis were sampled at three sites: De Hoop situated in the centre of the species distribution in the Fynbos biome; Steenkampskraal and Table Farm were ecotone populations situated in the western and eastern limits of the distribution, respectively. Interspecific analysis revealed that the two ecotone populations deviated slightly from the allometric relationship between body size and peak frequency for the African clade. In fact, the expected inverse relationship between body size and peak frequency was not evident across populations. Ecotone populations had significantly larger mean body sizes than the population at De Hoop (10.28 ± 1.08 g; 84.60 ± 0.82 kHz). However, one population in the ecotone had the highest frequency (Table Farm: 13.88 ± 0.87 g; 85.84 ± 0.73 kHz) while the other had the lowest (Steenkampskraal: 13.15 ± 0.95 g; 80.66 ± 0.50 kHz). Several hypotheses were considered to explain the patterns of echolocation and morphological variation observed. The larger body size of the ecotone populations may be explained by James' Rule or it may be an adaptation to the intrinsic habitat heterogeneity of ecotones as it affords these bats a greater niche width and possibly larger home ranges to access spatially separated resources. On the other hand, neither climatic (humidity hypothesis), habitat (foraging habitat hypothesis) nor dietary differences (prey detection hypothesis between populations were responsible for the observed peak frequency differences between populations. Nasal chamber area was the best predictor of peak frequency and there was no relationship between the area of the nasal chamber and body size. Thus, selection may have acted directly on peak frequency altering skull parameters directly involved in echolocation independently of body size. Within each population, females were larger and used higher frequencies than males, which implies a potential social role of peak frequency for R. capensis. Observed differences in peak frequency may be because R. capensis interacts with separate rhinolophid species at either end of its distribution (Steenkampskraal: R. swinnyi; Table Farm: R. darlingi) in addition to R. clivasus, which results in the evolution of local dialects to facilitate intraspecific communication. These local dialects, possibly brought about by differences in local ambient noise characteristics (e.g. chorusing insects), could be maintained via cultural transmission. However, the role of gene flow for the evolution of these local dialects between populations cannot be discounted without adequate genetic analyses. DA - 2009 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2009 T1 - Geographic variation in the echolocation calls of the endemic Cape horseshoe bat, Rhinolophus capensis (Chiroptera: Rhinolophidae) TI - Geographic variation in the echolocation calls of the endemic Cape horseshoe bat, Rhinolophus capensis (Chiroptera: Rhinolophidae) UR - http://hdl.handle.net/11427/8976 ER - en_ZA


Files in this item

This item appears in the following Collection(s)

Show simple item record