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
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
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