Obesity: a preliminary report of an introductory service-learning course on the role of pharmacy students in health promotion
- Srinivas, Sunitha C, Wrench, Wendy W, Karekazi, Catherine W, Radloff, Sarah E, Daya, Santylal
- Authors: Srinivas, Sunitha C , Wrench, Wendy W , Karekazi, Catherine W , Radloff, Sarah E , Daya, Santylal
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6454 , http://hdl.handle.net/10962/d1006833
- Description: Lifestyle diseases such as obesity have been neglected in developing countries partly due to a more urgent focus on infectious diseases in these countries. The incidence of obesity is on the increase in developing countries, with a marked rise in childhood obesity. A health promotioning service-learning principles required final year pharmacy students to prepare a pilot-tested computer-based quiz, using a pre- and post-intervention test design, along with other learning material, for participants at the 2007 Sasol National Festival of Science and Technology (SciFest). Interactive models, posters and information leaflets were used in explaining the prevention and control of obesity to learners. The results showed that the pre-existing knowledge of the participants was good. There was a further improvement after the educational intervention. Activities such as this are important in heightening awareness of obesity in learners as it is likely to reduce the incidence of obesity later in life. Furthermore, the activity also served to increase awareness of the role of pharmacists in the prevention of lifestyle diseases such as obesity.
- Full Text:
- Date Issued: 2009
- Authors: Srinivas, Sunitha C , Wrench, Wendy W , Karekazi, Catherine W , Radloff, Sarah E , Daya, Santylal
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6454 , http://hdl.handle.net/10962/d1006833
- Description: Lifestyle diseases such as obesity have been neglected in developing countries partly due to a more urgent focus on infectious diseases in these countries. The incidence of obesity is on the increase in developing countries, with a marked rise in childhood obesity. A health promotioning service-learning principles required final year pharmacy students to prepare a pilot-tested computer-based quiz, using a pre- and post-intervention test design, along with other learning material, for participants at the 2007 Sasol National Festival of Science and Technology (SciFest). Interactive models, posters and information leaflets were used in explaining the prevention and control of obesity to learners. The results showed that the pre-existing knowledge of the participants was good. There was a further improvement after the educational intervention. Activities such as this are important in heightening awareness of obesity in learners as it is likely to reduce the incidence of obesity later in life. Furthermore, the activity also served to increase awareness of the role of pharmacists in the prevention of lifestyle diseases such as obesity.
- Full Text:
- Date Issued: 2009
Factors affecting ethical judgement of South African chartered accountants
- Maree, Kevin W, Radloff, Sarah E
- Authors: Maree, Kevin W , Radloff, Sarah E
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: Article
- Identifier: vital:6073 , http://hdl.handle.net/10962/d1001647 , ISSN 1022-2529 , http://0-dx.doi.org.wam.seals.ac.za/10.1108/10222529200700001
- Description: The start of the twenty-first century was marred by a spate of company collapses that involved fraudulent accounting activity. In many cases, company executives, many of whom belonged to the accounting profession, perpetrated the fraud. As a result, internationally, the accounting profession has suffered an enormous loss of goodwill, and its reputation as a profession with integrity has been severely harmed. Accounting professionals are no longer accorded the high regard they commanded in the past. The consequences for the profession have been far-reaching: accounting now faces a long, uphill battle to restore its reputation and to regain the trust of the international business community. This study replicates two famous international studies in the South African context. The focus of the study was to establish whether factors such as the Code of Professional Conduct of the South African Institute of Chartered Accountants (SAICA), the corporate ethical environment and their age influence the ethical judgement of individual accountants. The first such study was conducted in the United States of America (USA), and it was followed by similar research in Turkey. The results of these two studies suggested very different factors that could influence accountants' ethical judgement. The study reported in this article investigated South African chartered accountants; and its results were similar to those obtained in the US study.
- Full Text:
- Date Issued: 2007
- Authors: Maree, Kevin W , Radloff, Sarah E
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: Article
- Identifier: vital:6073 , http://hdl.handle.net/10962/d1001647 , ISSN 1022-2529 , http://0-dx.doi.org.wam.seals.ac.za/10.1108/10222529200700001
- Description: The start of the twenty-first century was marred by a spate of company collapses that involved fraudulent accounting activity. In many cases, company executives, many of whom belonged to the accounting profession, perpetrated the fraud. As a result, internationally, the accounting profession has suffered an enormous loss of goodwill, and its reputation as a profession with integrity has been severely harmed. Accounting professionals are no longer accorded the high regard they commanded in the past. The consequences for the profession have been far-reaching: accounting now faces a long, uphill battle to restore its reputation and to regain the trust of the international business community. This study replicates two famous international studies in the South African context. The focus of the study was to establish whether factors such as the Code of Professional Conduct of the South African Institute of Chartered Accountants (SAICA), the corporate ethical environment and their age influence the ethical judgement of individual accountants. The first such study was conducted in the United States of America (USA), and it was followed by similar research in Turkey. The results of these two studies suggested very different factors that could influence accountants' ethical judgement. The study reported in this article investigated South African chartered accountants; and its results were similar to those obtained in the US study.
- Full Text:
- Date Issued: 2007
Cooperative wasp-killing by mixed-species colonies of honeybees, Apis cerana and Apis mellifera
- Tan, K, Yang, M-Y, Li, H, Zhang, Z-L, Radloff, Sarah E, Hepburn, H Randall
- Authors: Tan, K , Yang, M-Y , Li, H , Zhang, Z-L , Radloff, Sarah E , Hepburn, H Randall
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6838 , http://hdl.handle.net/10962/d1010979 , http://dx.doi.org/10.1007/s13592-011-0098-5
- Description: The cooperative defensive behaviour of mixed-species colonies of honeybees, Apis cerana and Apis mellifera, were tested against a predatory wasp, Vespa velutina. When vespine wasps hawk honeybees at their nest entrances, the difference in the numbers of bees involved in heat-balling among pure species and mixed-species colonies was not significantly different. However, in the mixed colonies, the numbers of A. cerana and A. mellifera workers involved in heat-balling were significantly different. The duration of heat-balling among these three groups was significantly different. During heat-balling, guard bees of both species in mixed colonies raised their thoracic temperatures and the core temperatures of the heat-balls were about 45°C, which is not significantly different from that of the pure species. These results suggest that the two species of honeybees can cooperate in joint heat-balling against the wasps, but A. cerana was more assertive in such defence.
- Full Text: false
- Date Issued: 2012
- Authors: Tan, K , Yang, M-Y , Li, H , Zhang, Z-L , Radloff, Sarah E , Hepburn, H Randall
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6838 , http://hdl.handle.net/10962/d1010979 , http://dx.doi.org/10.1007/s13592-011-0098-5
- Description: The cooperative defensive behaviour of mixed-species colonies of honeybees, Apis cerana and Apis mellifera, were tested against a predatory wasp, Vespa velutina. When vespine wasps hawk honeybees at their nest entrances, the difference in the numbers of bees involved in heat-balling among pure species and mixed-species colonies was not significantly different. However, in the mixed colonies, the numbers of A. cerana and A. mellifera workers involved in heat-balling were significantly different. The duration of heat-balling among these three groups was significantly different. During heat-balling, guard bees of both species in mixed colonies raised their thoracic temperatures and the core temperatures of the heat-balls were about 45°C, which is not significantly different from that of the pure species. These results suggest that the two species of honeybees can cooperate in joint heat-balling against the wasps, but A. cerana was more assertive in such defence.
- Full Text: false
- Date Issued: 2012
Social parasitism by honeybee workers (Apis mellifera capensis Escholtz): host finding and resistance of hybrid host colonies
- Neumann, Peter, Radloff, Sarah E, Moritz, Robin F A, Hepburn, H Randall, Reece, Sacha L
- Authors: Neumann, Peter , Radloff, Sarah E , Moritz, Robin F A , Hepburn, H Randall , Reece, Sacha L
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6907 , http://hdl.handle.net/10962/d1011860
- Description: We studied possible host finding and resistance mechanisms of host colonies in the context of social parasitism by Cape honeybee (Apis mellifera capensis) workers. Workers often join neighboring colonies by drifting, but long-range drifting (dispersal) to colonies far away from the maternal nests also rarely occurs. We tested the impact of queenstate and taxon of mother and host colonies on drifting and dispersing of workers and on the hosting of these workers in A. m. capensis, A. m. scutellata, and their natural hybrids. Workers were paint-marked according to colony and reintroduced into their queenright or queenless mother colonies. After 10 days, 579 out of 12,034 labeled workers were recaptured in foreign colonies. We found that drifting and dispersing represent different behaviors, which were differently affected by taxon and queenstate of both mother and host colonies. Hybrid workers drifted more often than A. m. capensis and A. m. scutellata. However, A. m. capensis workers dispersed more often than A. m. scutellata and the hybrids combined, and A. m. scutellata workers also dispersed more frequently than the hybrids. Dispersers from queenright A. m. capensis colonies were more often found in queenless host colonies and vice versa, indicating active host searching and/or a queenstate-discriminating guarding mechanism. Our data show that A. m. capensis workers disperse significantly more often than other races of A. mellifera, suggesting that dispersing represents a host finding mechanism. The lack of dispersal in hybrids and different hosting mechanisms of foreign workers by hybrid colonies may also be responsible for the stability of the natural hybrid zone between A. m. capensis and A. m. scutellata.
- Full Text:
- Date Issued: 2001
- Authors: Neumann, Peter , Radloff, Sarah E , Moritz, Robin F A , Hepburn, H Randall , Reece, Sacha L
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6907 , http://hdl.handle.net/10962/d1011860
- Description: We studied possible host finding and resistance mechanisms of host colonies in the context of social parasitism by Cape honeybee (Apis mellifera capensis) workers. Workers often join neighboring colonies by drifting, but long-range drifting (dispersal) to colonies far away from the maternal nests also rarely occurs. We tested the impact of queenstate and taxon of mother and host colonies on drifting and dispersing of workers and on the hosting of these workers in A. m. capensis, A. m. scutellata, and their natural hybrids. Workers were paint-marked according to colony and reintroduced into their queenright or queenless mother colonies. After 10 days, 579 out of 12,034 labeled workers were recaptured in foreign colonies. We found that drifting and dispersing represent different behaviors, which were differently affected by taxon and queenstate of both mother and host colonies. Hybrid workers drifted more often than A. m. capensis and A. m. scutellata. However, A. m. capensis workers dispersed more often than A. m. scutellata and the hybrids combined, and A. m. scutellata workers also dispersed more frequently than the hybrids. Dispersers from queenright A. m. capensis colonies were more often found in queenless host colonies and vice versa, indicating active host searching and/or a queenstate-discriminating guarding mechanism. Our data show that A. m. capensis workers disperse significantly more often than other races of A. mellifera, suggesting that dispersing represents a host finding mechanism. The lack of dispersal in hybrids and different hosting mechanisms of foreign workers by hybrid colonies may also be responsible for the stability of the natural hybrid zone between A. m. capensis and A. m. scutellata.
- Full Text:
- Date Issued: 2001
Apis florea in Jordan: source of the founder population
- Haddad, N, Fuchs, S, Hepburn, H Randall, Radloff, Sarah E
- Authors: Haddad, N , Fuchs, S , Hepburn, H Randall , Radloff, Sarah E
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6844 , http://hdl.handle.net/10962/d1011047
- Description: A recent isolated population of Apis florea has been reported from Aqaba in Jordan at the Red Sea, consisting of numerous colonies within a still limited range which apparently is expanding. This region is about 1500 km apart from its next occurrences in Sudan where it had been introduced and first detected in 1985 and about 2000 km apart from its next natural occurrences in Iran and Oman. These bees apparently have been imported by human transport, most likely by ship. This new location thus represents a major jump in the progression of the species still to fill a wide area of possible locations offering adequate living conditions. Here we attempt to track the possible origin of this new population by morphometric methods. This analysis indicated closest relation to A. florea from Oman, thus being the most likely source of this population.
- Full Text:
- Date Issued: 2009
- Authors: Haddad, N , Fuchs, S , Hepburn, H Randall , Radloff, Sarah E
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6844 , http://hdl.handle.net/10962/d1011047
- Description: A recent isolated population of Apis florea has been reported from Aqaba in Jordan at the Red Sea, consisting of numerous colonies within a still limited range which apparently is expanding. This region is about 1500 km apart from its next occurrences in Sudan where it had been introduced and first detected in 1985 and about 2000 km apart from its next natural occurrences in Iran and Oman. These bees apparently have been imported by human transport, most likely by ship. This new location thus represents a major jump in the progression of the species still to fill a wide area of possible locations offering adequate living conditions. Here we attempt to track the possible origin of this new population by morphometric methods. This analysis indicated closest relation to A. florea from Oman, thus being the most likely source of this population.
- Full Text:
- Date Issued: 2009
A scientific note on the natural merger of two honeybee colonies (Apis mellifera capensis)
- Neumann, Peter, Pirk, Christian W W, Hepburn, H Randall, Radloff, Sarah E
- Authors: Neumann, Peter , Pirk, Christian W W , Hepburn, H Randall , Radloff, Sarah E
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6912 , http://hdl.handle.net/10962/d1011875
- Description: Natural mergers of honeybee colonies are commonplace in tropical Africa (Hepburn and Radloff, 1998), but their consequences on organizational structure are unknown. Here we determine the spatial distribution and division of labor of workers (Apis mellifera capensis Esch.) following a merger of two colonies. Two unrelated colonies (each ~3000 bees) were placed in threeframe observation hives. When workers emerged from the sealed brood of each colony, they were individually labeled and reintroduced into their respective mother hives. They are referred to as cohorts Aand B, each comprising 300 workers of the same age. The behaviors and positions of all labeled workers and queens were recorded twice daily for 24 days (Kolmes, 1989; Pirk et al., 2000). On day 14 colony B was dequeened, left its nest and merged with colony A on day 15.
- Full Text:
- Date Issued: 2001
- Authors: Neumann, Peter , Pirk, Christian W W , Hepburn, H Randall , Radloff, Sarah E
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6912 , http://hdl.handle.net/10962/d1011875
- Description: Natural mergers of honeybee colonies are commonplace in tropical Africa (Hepburn and Radloff, 1998), but their consequences on organizational structure are unknown. Here we determine the spatial distribution and division of labor of workers (Apis mellifera capensis Esch.) following a merger of two colonies. Two unrelated colonies (each ~3000 bees) were placed in threeframe observation hives. When workers emerged from the sealed brood of each colony, they were individually labeled and reintroduced into their respective mother hives. They are referred to as cohorts Aand B, each comprising 300 workers of the same age. The behaviors and positions of all labeled workers and queens were recorded twice daily for 24 days (Kolmes, 1989; Pirk et al., 2000). On day 14 colony B was dequeened, left its nest and merged with colony A on day 15.
- Full Text:
- Date Issued: 2001
Multivariate morphometric analysis of Apis cerana of southern mainland Asia
- Hepburn, H Randall, Radloff, Sarah E, Hepburn, Colleen, Fuchs, S, Otis, G W, Sein, M M, Aung, H L, Pham, H T, Tam, D Q, Nuru, A M, Ken, T
- Authors: Hepburn, H Randall , Radloff, Sarah E , Hepburn, Colleen , Fuchs, S , Otis, G W , Sein, M M , Aung, H L , Pham, H T , Tam, D Q , Nuru, A M , Ken, T
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6906 , http://hdl.handle.net/10962/d1011859
- Description: Multivariate morphometric analyses were performed on a series of worker honeybees, Apis cerana, representing 557 colonies from all of southern mainland Asia extending from Afghanistan to Vietnam south of the Himalayas. Scores from the principal components analysis revealed five statistically separable but not entirely distinct morphoclusters of bees: (1) the Hindu Kush, Kashmir, N. Myanmar, N. Vietnam and S. China; (2) Himachal Pradesh region of N. India; (3) N. India, Nepal; (4) central and S. Myanmar and Vietnam, Cambodia, Thailand, S. China and peninsular Malaysia; (5) central and S. India. The major morphoclusters are distributed coherently with the different climatic zones of the region. While populations are definable, nomenclatural adjustments remain for the future.
- Full Text:
- Date Issued: 2005
- Authors: Hepburn, H Randall , Radloff, Sarah E , Hepburn, Colleen , Fuchs, S , Otis, G W , Sein, M M , Aung, H L , Pham, H T , Tam, D Q , Nuru, A M , Ken, T
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6906 , http://hdl.handle.net/10962/d1011859
- Description: Multivariate morphometric analyses were performed on a series of worker honeybees, Apis cerana, representing 557 colonies from all of southern mainland Asia extending from Afghanistan to Vietnam south of the Himalayas. Scores from the principal components analysis revealed five statistically separable but not entirely distinct morphoclusters of bees: (1) the Hindu Kush, Kashmir, N. Myanmar, N. Vietnam and S. China; (2) Himachal Pradesh region of N. India; (3) N. India, Nepal; (4) central and S. Myanmar and Vietnam, Cambodia, Thailand, S. China and peninsular Malaysia; (5) central and S. India. The major morphoclusters are distributed coherently with the different climatic zones of the region. While populations are definable, nomenclatural adjustments remain for the future.
- Full Text:
- Date Issued: 2005
Intra- and interspecific brood recognition in pure and mixed-species honeybee colonies, Apis cerana and A. mellifera
- Tan, K, Yang, M-X, Radloff, Sarah E, Yu, Y, Pirk, C W W, Hepburn, H Randall
- Authors: Tan, K , Yang, M-X , Radloff, Sarah E , Yu, Y , Pirk, C W W , Hepburn, H Randall
- Date: 2009
- Subjects: Apis mellifera Apis cerana
- Language: English
- Type: text , Article
- Identifier: vital:6837 , http://hdl.handle.net/10962/d1010962 , http://dx.doi.org/10.1051/apido/2009003
- Description: We studied the effects of mixed honeybee colonies of Apis mellifera and Apis cerana on the intraspecific and interspecific recognition of female brood stages in the honeybees A. cerana and A. mellifera by transferring brood combs between queenright colonies. In the intraspecific tests, significantly more larvae were removed in A. cerana than in A. mellifera, whilst significantly fewer eggs and pupae were removed in A. cerana than in A. mellifera. In the interspecific tests, A. cerana colonies removed significantly more larvae and pupae of A. mellifera than the same brood stages of A. cerana were removed by A. mellifera. We show there are highly significant differences in both intraspecific and interspecific brood recognition between A. cerana and A. mellifera and that brood recognition operates with decreasing intensity with increasing developmental age within species. This suggests that worker policing in egg removal is a first line of defense against heterospecific social parasites.
- Full Text: false
- Date Issued: 2009
- Authors: Tan, K , Yang, M-X , Radloff, Sarah E , Yu, Y , Pirk, C W W , Hepburn, H Randall
- Date: 2009
- Subjects: Apis mellifera Apis cerana
- Language: English
- Type: text , Article
- Identifier: vital:6837 , http://hdl.handle.net/10962/d1010962 , http://dx.doi.org/10.1051/apido/2009003
- Description: We studied the effects of mixed honeybee colonies of Apis mellifera and Apis cerana on the intraspecific and interspecific recognition of female brood stages in the honeybees A. cerana and A. mellifera by transferring brood combs between queenright colonies. In the intraspecific tests, significantly more larvae were removed in A. cerana than in A. mellifera, whilst significantly fewer eggs and pupae were removed in A. cerana than in A. mellifera. In the interspecific tests, A. cerana colonies removed significantly more larvae and pupae of A. mellifera than the same brood stages of A. cerana were removed by A. mellifera. We show there are highly significant differences in both intraspecific and interspecific brood recognition between A. cerana and A. mellifera and that brood recognition operates with decreasing intensity with increasing developmental age within species. This suggests that worker policing in egg removal is a first line of defense against heterospecific social parasites.
- Full Text: false
- Date Issued: 2009
Parasitic Cape bees in the northern regions of South Africa: source of the founder population
- Neumann, Peter, Radloff, Sarah E, Hepburn, H Randall
- Authors: Neumann, Peter , Radloff, Sarah E , Hepburn, H Randall
- Date: 2002
- Language: English
- Type: text , Article
- Identifier: vital:6908 , http://hdl.handle.net/10962/d1011861
- Description: Multivariate discriminant analyses of nine standard morphometric characters of honeybee workers were used to track the origin of a social parasitic pseudo-clone of thelytokous laying workers that have invaded colonies of Apis mellifera scutellata in South Africa. Twenty social parasitic workers were sampled from both of two infested A. m. scutellata colonies at two distant apiaries (Graskop and Heilbronn, about 390 km apart) and compared with data obtained from 80 colonies in four different geographical zones (zone I: thelytokous A. m. capensis morphocluster; zone II: natural thelytokous hybrids between A. m. capensis and A. m. scutellata; zone III: thelytokous A. m. scutellata morphocluster; zone IV: an arrhenotokous A. m. scutellata morphocluster). Thelytokous laying workers occur naturally in zones I-III. Highly significant morphometric differences were found among the bees in the four zones. The data support the conclusion that the social parasitic workers belong to the thelytokous A. m. capensis morphocluster. It is most likely that the social parasitic workers originated from the heart of the Cape bee's distribution range in the Western Cape region in zone I. Morphometric analysis makes it feasible to restrict the possible origin of the social parasitic workers from the natural distribution range of thelytoky (approximately 240 000 km2) down to about 12 000 km2, which represents a resolution capacity of about 95%.
- Full Text:
- Date Issued: 2002
- Authors: Neumann, Peter , Radloff, Sarah E , Hepburn, H Randall
- Date: 2002
- Language: English
- Type: text , Article
- Identifier: vital:6908 , http://hdl.handle.net/10962/d1011861
- Description: Multivariate discriminant analyses of nine standard morphometric characters of honeybee workers were used to track the origin of a social parasitic pseudo-clone of thelytokous laying workers that have invaded colonies of Apis mellifera scutellata in South Africa. Twenty social parasitic workers were sampled from both of two infested A. m. scutellata colonies at two distant apiaries (Graskop and Heilbronn, about 390 km apart) and compared with data obtained from 80 colonies in four different geographical zones (zone I: thelytokous A. m. capensis morphocluster; zone II: natural thelytokous hybrids between A. m. capensis and A. m. scutellata; zone III: thelytokous A. m. scutellata morphocluster; zone IV: an arrhenotokous A. m. scutellata morphocluster). Thelytokous laying workers occur naturally in zones I-III. Highly significant morphometric differences were found among the bees in the four zones. The data support the conclusion that the social parasitic workers belong to the thelytokous A. m. capensis morphocluster. It is most likely that the social parasitic workers originated from the heart of the Cape bee's distribution range in the Western Cape region in zone I. Morphometric analysis makes it feasible to restrict the possible origin of the social parasitic workers from the natural distribution range of thelytoky (approximately 240 000 km2) down to about 12 000 km2, which represents a resolution capacity of about 95%.
- Full Text:
- Date Issued: 2002
Spatio-temporal variability of larval abundance and settlement of Perna perna: differential delivery of mussels
- Porri, Francesca, McQuaid, Christopher D, Radloff, Sarah E
- Authors: Porri, Francesca , McQuaid, Christopher D , Radloff, Sarah E
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6877 , http://hdl.handle.net/10962/d1011625 , http://dx.doi.org/10.3354/meps315141
- Description: We examined larval availability and settlement of the intertidal mussel Perna perna simultaneously at different spatial and temporal scales using a nested design at 2 sites, 3 km apart on the south coast of South Africa. Each site had 3 locations (300 m apart) where 5 artificial settler collectors were placed about 20 cm apart. Collectors were replaced on temporal scales varying from fortnightly (for 16 mo) to daily (2 series of 15 to 20 d). Each intertidal location was paired with an inshore location (these too were 300 m apart) within 500 m of the shore, where larval availability was measured by 3 vertical plankton hauls collected on the same dates as for settler sampling. There was strong temporal variation in abundances of larvae and settlers, and no correlation (r always < 0.14) was found between the two. Larvae were abundant only at the start of sampling and rare for the rest of the study, while distinct peaks in settler numbers occurred later. No spatial effect was detected for larval availability, while there was strong spatial variation in settlement at the location level. These results indicate that, on scales of 100s of m to km, delivery of larvae from the nearshore water column onto the shore is strongly differential, with some locations consistently receiving more settlers than others. We conclude that, at these sites, the patchiness in settlement observed on scales of 100s of m depends on differential delivery, rather than differential offshore distribution of larvae. We suggest that differential delivery is due to the effect of nearshore bottom topography on local hydrodynamics.
- Full Text:
- Date Issued: 2006
- Authors: Porri, Francesca , McQuaid, Christopher D , Radloff, Sarah E
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6877 , http://hdl.handle.net/10962/d1011625 , http://dx.doi.org/10.3354/meps315141
- Description: We examined larval availability and settlement of the intertidal mussel Perna perna simultaneously at different spatial and temporal scales using a nested design at 2 sites, 3 km apart on the south coast of South Africa. Each site had 3 locations (300 m apart) where 5 artificial settler collectors were placed about 20 cm apart. Collectors were replaced on temporal scales varying from fortnightly (for 16 mo) to daily (2 series of 15 to 20 d). Each intertidal location was paired with an inshore location (these too were 300 m apart) within 500 m of the shore, where larval availability was measured by 3 vertical plankton hauls collected on the same dates as for settler sampling. There was strong temporal variation in abundances of larvae and settlers, and no correlation (r always < 0.14) was found between the two. Larvae were abundant only at the start of sampling and rare for the rest of the study, while distinct peaks in settler numbers occurred later. No spatial effect was detected for larval availability, while there was strong spatial variation in settlement at the location level. These results indicate that, on scales of 100s of m to km, delivery of larvae from the nearshore water column onto the shore is strongly differential, with some locations consistently receiving more settlers than others. We conclude that, at these sites, the patchiness in settlement observed on scales of 100s of m depends on differential delivery, rather than differential offshore distribution of larvae. We suggest that differential delivery is due to the effect of nearshore bottom topography on local hydrodynamics.
- Full Text:
- Date Issued: 2006
Temporal scales of variation in settlement and recruitment of the mussel Perna perna (Linnaeus, 1758)
- Porri, Francesca, McQuaid, Christopher D, Radloff, Sarah E
- Authors: Porri, Francesca , McQuaid, Christopher D , Radloff, Sarah E
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6963 , http://hdl.handle.net/10962/d1012026 , http://dx.doi.org/10.1016/j.jembe.2005.11.008
- Description: Population dynamics of many intertidal organisms are strongly affected by the abundance and distribution of larvae arriving on the shore. In particular, not only absolute numbers of settlers but also the degree of synchronisation of settlement can have a strong influence on whether density-dependent or density-independent processes shape adult shape populations. Temporal variation in rates of settlement and recruitment of the mussel Perna perna on the south coast of South Africa was investigated using a nested spatial design at different temporal scales. Variability in settlement at spring tides was examined at two temporal scales: lunar (to investigate the effect of state of the moon on settlement) and tidal (to investigate the influence of state of the tide on mussel settlement). Recruitment over neap tides was examined at one temporal scale, fortnight (to investigate the effect of date on mussel recruitment). Strong temporal variation was evident for both settlement and recruitment, but not at all time scales. Distinct peaks of settler/recruit abundance were observed during the lunar and neap tide studies. Recruitment intensity differed over the course of the year, and pulsing of recruitment was generally synchronised among locations. However, the strength of pulsing differed dramatically among locations, giving a significant interaction between fortnight and location. The finest temporal scale, investigated in the tidal study, did not reveal a significant effect of the state of the tide on settlement. The state of the moon (new or full) was not significant as a main factor (p = 0.052), although generally more settlers arrived on the shore during new moon. Phase of the moon appeared to have an effect on settler abundances, but only when and where densities were high.
- Full Text:
- Date Issued: 2006
- Authors: Porri, Francesca , McQuaid, Christopher D , Radloff, Sarah E
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6963 , http://hdl.handle.net/10962/d1012026 , http://dx.doi.org/10.1016/j.jembe.2005.11.008
- Description: Population dynamics of many intertidal organisms are strongly affected by the abundance and distribution of larvae arriving on the shore. In particular, not only absolute numbers of settlers but also the degree of synchronisation of settlement can have a strong influence on whether density-dependent or density-independent processes shape adult shape populations. Temporal variation in rates of settlement and recruitment of the mussel Perna perna on the south coast of South Africa was investigated using a nested spatial design at different temporal scales. Variability in settlement at spring tides was examined at two temporal scales: lunar (to investigate the effect of state of the moon on settlement) and tidal (to investigate the influence of state of the tide on mussel settlement). Recruitment over neap tides was examined at one temporal scale, fortnight (to investigate the effect of date on mussel recruitment). Strong temporal variation was evident for both settlement and recruitment, but not at all time scales. Distinct peaks of settler/recruit abundance were observed during the lunar and neap tide studies. Recruitment intensity differed over the course of the year, and pulsing of recruitment was generally synchronised among locations. However, the strength of pulsing differed dramatically among locations, giving a significant interaction between fortnight and location. The finest temporal scale, investigated in the tidal study, did not reveal a significant effect of the state of the tide on settlement. The state of the moon (new or full) was not significant as a main factor (p = 0.052), although generally more settlers arrived on the shore during new moon. Phase of the moon appeared to have an effect on settler abundances, but only when and where densities were high.
- Full Text:
- Date Issued: 2006
The honeybees, Apis mellifera Linnaeus (Hymenoptera: Apidae) of woodland savanna of southeastern Africa
- Radloff, Sarah E, Hepburn, H Randall, Villet, Martin H
- Authors: Radloff, Sarah E , Hepburn, H Randall , Villet, Martin H
- Date: 1997
- Language: English
- Type: Article
- Identifier: vital:6829 , http://hdl.handle.net/10962/d1012341
- Description: The morphometric characters and sting pheromones of worker honeybees, Apis mellifera Linnaeus, were analysed by multivariate methods to identify discrete populations in the southeastern woodland savanna of Africa. A discrete population in Mozambique is classified as A. m. litorea Smith, a second in Zimbabwe as A. m. scutellata Lepeletier and a third group in southwestern Zambia as A.m. adansonii Latreille. A zone of introgression between the last two subspecies occurs in south-central Zambia and in the Zambezi Valley.
- Full Text:
- Date Issued: 1997
- Authors: Radloff, Sarah E , Hepburn, H Randall , Villet, Martin H
- Date: 1997
- Language: English
- Type: Article
- Identifier: vital:6829 , http://hdl.handle.net/10962/d1012341
- Description: The morphometric characters and sting pheromones of worker honeybees, Apis mellifera Linnaeus, were analysed by multivariate methods to identify discrete populations in the southeastern woodland savanna of Africa. A discrete population in Mozambique is classified as A. m. litorea Smith, a second in Zimbabwe as A. m. scutellata Lepeletier and a third group in southwestern Zambia as A.m. adansonii Latreille. A zone of introgression between the last two subspecies occurs in south-central Zambia and in the Zambezi Valley.
- Full Text:
- Date Issued: 1997
Bee-hawking by the wasp, Vespa velutina, on the honeybees Apis cerana and A. mellifera
- Tan, K, Radloff, Sarah E, Li, J J, Hepburn, H Randall, Yang, Ming-Xian, Zhang, L J, Neumann, Peter
- Authors: Tan, K , Radloff, Sarah E , Li, J J , Hepburn, H Randall , Yang, Ming-Xian , Zhang, L J , Neumann, Peter
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6941 , http://hdl.handle.net/10962/d1011965
- Description: The vespine wasps, Vespa velutina, specialise in hawking honeybee foragers returning to their nests. We studied their behaviour in China using native Apis cerana and introduced A. mellifera colonies. When the wasps are hawking, A. cerana recruits threefold more guard bees to stave off predation than A. mellifera. The former also utilises wing shimmering as a visual pattern disruption mechanism, which is not shown by A. mellifera. A. cerana foragers halve the time of normal flight needed to dart into the nest entrance, while A. mellifera actually slows down in sashaying flight manoeuvres. V. velutina preferentially hawks A. mellifera foragers when both A. mellifera and A. cerana occur in the same apiary. The pace of wasp-hawking was highest in mid-summer but the frequency of hawking wasps was three times higher at A. mellifera colonies than at the A. cerana colonies. The wasps were taking A. mellifera foragers at a frequency eightfold greater than A. cerana foragers. The final hawking success rates of the wasps were about three times higher for A. mellifera foragers than for A. cerana. The relative success of native A. cerana over European A. mellifera in thwarting predation by the wasp V. velutina is interpreted as the result of co-evolution between the Asian wasp and honeybee, respectively.
- Full Text:
- Date Issued: 2007
- Authors: Tan, K , Radloff, Sarah E , Li, J J , Hepburn, H Randall , Yang, Ming-Xian , Zhang, L J , Neumann, Peter
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6941 , http://hdl.handle.net/10962/d1011965
- Description: The vespine wasps, Vespa velutina, specialise in hawking honeybee foragers returning to their nests. We studied their behaviour in China using native Apis cerana and introduced A. mellifera colonies. When the wasps are hawking, A. cerana recruits threefold more guard bees to stave off predation than A. mellifera. The former also utilises wing shimmering as a visual pattern disruption mechanism, which is not shown by A. mellifera. A. cerana foragers halve the time of normal flight needed to dart into the nest entrance, while A. mellifera actually slows down in sashaying flight manoeuvres. V. velutina preferentially hawks A. mellifera foragers when both A. mellifera and A. cerana occur in the same apiary. The pace of wasp-hawking was highest in mid-summer but the frequency of hawking wasps was three times higher at A. mellifera colonies than at the A. cerana colonies. The wasps were taking A. mellifera foragers at a frequency eightfold greater than A. cerana foragers. The final hawking success rates of the wasps were about three times higher for A. mellifera foragers than for A. cerana. The relative success of native A. cerana over European A. mellifera in thwarting predation by the wasp V. velutina is interpreted as the result of co-evolution between the Asian wasp and honeybee, respectively.
- Full Text:
- Date Issued: 2007
The wing coupling apparatus and the morphometric analysis of honeybee populations
- Hepburn, H Randall, Radloff, Sarah E
- Authors: Hepburn, H Randall , Radloff, Sarah E
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6904 , http://hdl.handle.net/10962/d1011760
- Description: Significant differences between countries were found in the distribution of the number of hamuli within Apis andreniformis, A. florea, A. cerana and A. koschevnikovi. The mean hamuli numbers for Apis mellifera intermissa differed significantly among localities in Algeria. Significant differences in intercolonial variability between countries were found within A. cerana. There was no significant infraspecific variability within A. andreniformis, A. florea, A. koschevnikovi and A. m. intermissa. Significant differences in the mean number of hamuli occur between A. m. intermissa and A. andreniformis, A. florea and A. cerana; also between A. cerana/A. koschevnikovi and A. andreniformis and A. florea. Significant differences were found in the distribution and variability of the number of hamuli between species (populations). The mean numbers of hamuli for A. andreniformis differed from those of A. florea. Both these population means differed from those of A. cerana, A. koschevnikovi and A. m. intermissa. No significant differences were found between A. cerana and A. koschevnikovi. When the analysis included data for A. dorsata, A. nigrocincta, A. m. carnica, A. m. caucasica and A. m. ligustica, the results showed significant differences in hamuli numbers between A. andreniformis/A. florea and A. cerana/A. koschevnikovi/A. nigrocincta and A. m. intermissa/A. m. carnica/A. m. caucasica/A. m. ligustica. Hamuli numbers in A. dorsata significantly differed from those of other populations except A. m. intermissa. These results show that hamuli numbers are useful in the classification of honeybee populations. Whether hamuli would be useful in multivariate analysis depends on the correlation between the number of hamuli and the other characters used.
- Full Text:
- Date Issued: 2004
- Authors: Hepburn, H Randall , Radloff, Sarah E
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6904 , http://hdl.handle.net/10962/d1011760
- Description: Significant differences between countries were found in the distribution of the number of hamuli within Apis andreniformis, A. florea, A. cerana and A. koschevnikovi. The mean hamuli numbers for Apis mellifera intermissa differed significantly among localities in Algeria. Significant differences in intercolonial variability between countries were found within A. cerana. There was no significant infraspecific variability within A. andreniformis, A. florea, A. koschevnikovi and A. m. intermissa. Significant differences in the mean number of hamuli occur between A. m. intermissa and A. andreniformis, A. florea and A. cerana; also between A. cerana/A. koschevnikovi and A. andreniformis and A. florea. Significant differences were found in the distribution and variability of the number of hamuli between species (populations). The mean numbers of hamuli for A. andreniformis differed from those of A. florea. Both these population means differed from those of A. cerana, A. koschevnikovi and A. m. intermissa. No significant differences were found between A. cerana and A. koschevnikovi. When the analysis included data for A. dorsata, A. nigrocincta, A. m. carnica, A. m. caucasica and A. m. ligustica, the results showed significant differences in hamuli numbers between A. andreniformis/A. florea and A. cerana/A. koschevnikovi/A. nigrocincta and A. m. intermissa/A. m. carnica/A. m. caucasica/A. m. ligustica. Hamuli numbers in A. dorsata significantly differed from those of other populations except A. m. intermissa. These results show that hamuli numbers are useful in the classification of honeybee populations. Whether hamuli would be useful in multivariate analysis depends on the correlation between the number of hamuli and the other characters used.
- Full Text:
- Date Issued: 2004
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