Evolution of foraging behaviour: Deep intra-generic genetic divergence between territorial and non-territorial southern African patellid limpets
- Mmonwa, Kolobe L, Teske, Peter R, McQuaid, Christopher D, Barker, Nigel P
- Authors: Mmonwa, Kolobe L , Teske, Peter R , McQuaid, Christopher D , Barker, Nigel P
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444798 , vital:74299 , https://doi.org/10.1016/j.ympev.2017.05.024
- Description: Southern Africa is a biodiversity hotspot of patellid limpets, with three genera (Helcion, Cymbula and Scutellastra) identified and described in the region. Scutellastra is the most diverse and most frequently studied of these and, along with Cymbula, includes species with territorial and non-territorial foraging behaviours. We used three mitochondrial markers (12S rRNA, 16S rRNA and COI) and one nuclear marker (ATPSβ intron) to assess evolutionary relationships among species of Cymbula and Scutellastra with these two foraging behaviours and to identify which foraging mode is the more ancient. Maximum Likelihood and Bayesian Inference phylogenetic analyses revealed that the species sharing a foraging type are monophyletic in both genera. Territoriality is a derived character, as the clades with this foraging type are nested within a tree that otherwise comprises non-territorial taxa. These include Helcion, which was recovered as sister to the Cymbula/Scutellastra clade, and the next basal genus, Patella, which is ancestral to all southern African patellogastropods. Deep genetic divergence between the two foraging traits reflects strong adaptive effects of resource partitioning in the evolution of southern African patellid limpets.
- Full Text:
- Date Issued: 2017
- Authors: Mmonwa, Kolobe L , Teske, Peter R , McQuaid, Christopher D , Barker, Nigel P
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444798 , vital:74299 , https://doi.org/10.1016/j.ympev.2017.05.024
- Description: Southern Africa is a biodiversity hotspot of patellid limpets, with three genera (Helcion, Cymbula and Scutellastra) identified and described in the region. Scutellastra is the most diverse and most frequently studied of these and, along with Cymbula, includes species with territorial and non-territorial foraging behaviours. We used three mitochondrial markers (12S rRNA, 16S rRNA and COI) and one nuclear marker (ATPSβ intron) to assess evolutionary relationships among species of Cymbula and Scutellastra with these two foraging behaviours and to identify which foraging mode is the more ancient. Maximum Likelihood and Bayesian Inference phylogenetic analyses revealed that the species sharing a foraging type are monophyletic in both genera. Territoriality is a derived character, as the clades with this foraging type are nested within a tree that otherwise comprises non-territorial taxa. These include Helcion, which was recovered as sister to the Cymbula/Scutellastra clade, and the next basal genus, Patella, which is ancestral to all southern African patellogastropods. Deep genetic divergence between the two foraging traits reflects strong adaptive effects of resource partitioning in the evolution of southern African patellid limpets.
- Full Text:
- Date Issued: 2017
A comparison of genetic structure in two low-dispersal crabs from the Wild Coast, South Africa
- Qhaji, Y, Jansen van Vuuren, Bettine, Papadopoulos, Isabelle, McQuaid, Christopher D, Teske, Peter R
- Authors: Qhaji, Y , Jansen van Vuuren, Bettine , Papadopoulos, Isabelle , McQuaid, Christopher D , Teske, Peter R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444770 , vital:74297 , https://doi.org/10.2989/1814232X.2015.1077474
- Description: The Wild Coast in south-eastern South Africa is strongly influenced by the warm, southward-flowing Agulhas Current. This current has a significant impact on dispersal in the coastal biota of the region, and facilitates high levels of connectivity among populations. However, it is not known how the region's high-velocity hydrology affects genetic population structure in endemic estuarine species, populations of which are frequently isolated from the sea. Here, we compared genetic structure in two estuarine crabs of the family Hymenosomatidae. Both are presumed to have low dispersal potential, but they differ in terms of their life histories. Hymenosoma longicrure has abbreviated larval development and can complete its entire life cycle within estuaries, whereas Neorhynchoplax bovis is a direct developer that lacks planktonic larvae.
- Full Text:
- Date Issued: 2015
- Authors: Qhaji, Y , Jansen van Vuuren, Bettine , Papadopoulos, Isabelle , McQuaid, Christopher D , Teske, Peter R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444770 , vital:74297 , https://doi.org/10.2989/1814232X.2015.1077474
- Description: The Wild Coast in south-eastern South Africa is strongly influenced by the warm, southward-flowing Agulhas Current. This current has a significant impact on dispersal in the coastal biota of the region, and facilitates high levels of connectivity among populations. However, it is not known how the region's high-velocity hydrology affects genetic population structure in endemic estuarine species, populations of which are frequently isolated from the sea. Here, we compared genetic structure in two estuarine crabs of the family Hymenosomatidae. Both are presumed to have low dispersal potential, but they differ in terms of their life histories. Hymenosoma longicrure has abbreviated larval development and can complete its entire life cycle within estuaries, whereas Neorhynchoplax bovis is a direct developer that lacks planktonic larvae.
- Full Text:
- Date Issued: 2015
Coastal topography drives genetic structure in marine mussels
- Nicastro, Katy R, Zardi, Gerardo I, McQuaid, Christopher D, Teske, Peter R, Barker, Nigel P
- Authors: Nicastro, Katy R , Zardi, Gerardo I , McQuaid, Christopher D , Teske, Peter R , Barker, Nigel P
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445634 , vital:74409 , https://doi.org/10.3354/meps07607
- Description: Understanding population connectivity is fundamental to ecology, and, for sedentary organisms, connectivity is achieved through larval dispersal. We tested whether coastal topography influences genetic structure in Perna perna mussels by comparing populations inside bays and on the open coast. Higher hydrodynamic stress on the open coast produces higher mortality and thus genetic turnover. Populations on the open coast had fewer private haplotypes and less genetic endemism than those inside bays. Gene flow analysis showed that bays act as source populations, with greater migration rates out of bays than into them. Differences in genetic structure on scales of 10s of kilometres show that coastal configuration strongly affects selection, larval dispersal and haplotype diversity.
- Full Text: false
- Date Issued: 2008
- Authors: Nicastro, Katy R , Zardi, Gerardo I , McQuaid, Christopher D , Teske, Peter R , Barker, Nigel P
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445634 , vital:74409 , https://doi.org/10.3354/meps07607
- Description: Understanding population connectivity is fundamental to ecology, and, for sedentary organisms, connectivity is achieved through larval dispersal. We tested whether coastal topography influences genetic structure in Perna perna mussels by comparing populations inside bays and on the open coast. Higher hydrodynamic stress on the open coast produces higher mortality and thus genetic turnover. Populations on the open coast had fewer private haplotypes and less genetic endemism than those inside bays. Gene flow analysis showed that bays act as source populations, with greater migration rates out of bays than into them. Differences in genetic structure on scales of 10s of kilometres show that coastal configuration strongly affects selection, larval dispersal and haplotype diversity.
- Full Text: false
- Date Issued: 2008
The relationship between human exploitation pressure and condition of mussel populations along the south coast of South Africa
- Rius, Marc, Kaehler, Sven, McQuaid, Christopher D
- Authors: Rius, Marc , Kaehler, Sven , McQuaid, Christopher D
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6913 , http://hdl.handle.net/10962/d1011876
- Description: Human exploitation of intertidal organisms in South Africa is an ancient activity based principally on mussels. We studied mussel populations and patterns of exploitation along a 160-km stretch of the south coast. Photographs (100 per site) were taken of the intertidal rocks at each of 14 sites, covering a range of exploitation intensities. Percentage cover was negatively correlated with number of mussel patches and positively correlated with mean shell width. PCA analysis identified groups of sites: a) accessible and unprotected sites: low cover, small mussels, patchy distribution; b) inaccessible sites and sites next to, or within, nature reserves: high percentage cover, large animals, less patchy distributions. Affluent coastal settlements also seem to confer protection against harvesting. Harvester distribution was examined by aerial surveys and combined with information on distance to the nearest beach access point and number of households within 7 km for each site. Sites within reserves and inaccessible sites had low densities of collectors, whereas sites near urban areas and in the Ciskei had the highest densities. All correlations between indicators of human exploitation and condition of mussel populations were non-significant. However, number of collectors showed positive trends with number of patches and negative trends for the two other variables. The results indicate much lower levels of exploitation than in the neighouring Transkei region, and suggest a high degree of background variability in mussel population structure.
- Full Text:
- Date Issued: 2006
- Authors: Rius, Marc , Kaehler, Sven , McQuaid, Christopher D
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6913 , http://hdl.handle.net/10962/d1011876
- Description: Human exploitation of intertidal organisms in South Africa is an ancient activity based principally on mussels. We studied mussel populations and patterns of exploitation along a 160-km stretch of the south coast. Photographs (100 per site) were taken of the intertidal rocks at each of 14 sites, covering a range of exploitation intensities. Percentage cover was negatively correlated with number of mussel patches and positively correlated with mean shell width. PCA analysis identified groups of sites: a) accessible and unprotected sites: low cover, small mussels, patchy distribution; b) inaccessible sites and sites next to, or within, nature reserves: high percentage cover, large animals, less patchy distributions. Affluent coastal settlements also seem to confer protection against harvesting. Harvester distribution was examined by aerial surveys and combined with information on distance to the nearest beach access point and number of households within 7 km for each site. Sites within reserves and inaccessible sites had low densities of collectors, whereas sites near urban areas and in the Ciskei had the highest densities. All correlations between indicators of human exploitation and condition of mussel populations were non-significant. However, number of collectors showed positive trends with number of patches and negative trends for the two other variables. The results indicate much lower levels of exploitation than in the neighouring Transkei region, and suggest a high degree of background variability in mussel population structure.
- Full Text:
- Date Issued: 2006
The Southern Ocean Group at Rhodes University: seventeen years of biological oceanography in the Southern Ocean reviewed
- McQuaid, Christopher D, Froneman, P William
- Authors: McQuaid, Christopher D , Froneman, P William
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6834 , http://hdl.handle.net/10962/d1010423
- Description: This paper reviews the main findings of the Southern Ocean Group at Rhodes University over the last 17 years. A primary contribution has been the development of conceptual models of the physical-biological driving mechanisms that support enormous seasonal populations of land-based top predators at the Prince Edward Islands. Collectively, these models are referred to as the life-support system of the islands. Near-shore subcomponents of the ecosystem, including inshore feeding predators, are largely supported by autochthonous primary production of kelps and localized diatom blooms. These energy sources feed indirectly into top predator populations via the benthic communities. A crucial link is formed by the bottom-dwelling shrimp, Nauticaris marionis, which feeds largely on benthic species and detritus and is eaten by a number of diving seabirds. The frontal systems that lie north and south of the islands are important feeding grounds for offshore feeding birds. A decadal-scale southward shift in the position of the Sub-antarctic Front towards the islands is reflected in increases in populations of these species. , Rhodes Centenary issue
- Full Text:
- Date Issued: 2004
- Authors: McQuaid, Christopher D , Froneman, P William
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6834 , http://hdl.handle.net/10962/d1010423
- Description: This paper reviews the main findings of the Southern Ocean Group at Rhodes University over the last 17 years. A primary contribution has been the development of conceptual models of the physical-biological driving mechanisms that support enormous seasonal populations of land-based top predators at the Prince Edward Islands. Collectively, these models are referred to as the life-support system of the islands. Near-shore subcomponents of the ecosystem, including inshore feeding predators, are largely supported by autochthonous primary production of kelps and localized diatom blooms. These energy sources feed indirectly into top predator populations via the benthic communities. A crucial link is formed by the bottom-dwelling shrimp, Nauticaris marionis, which feeds largely on benthic species and detritus and is eaten by a number of diving seabirds. The frontal systems that lie north and south of the islands are important feeding grounds for offshore feeding birds. A decadal-scale southward shift in the position of the Sub-antarctic Front towards the islands is reflected in increases in populations of these species. , Rhodes Centenary issue
- Full Text:
- Date Issued: 2004
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