Endothermy and chorusing behaviour in the African platypleurine cicada Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae)
- Villet, Martin H, Sanborn, Allen F, Phillips, P K
- Authors: Villet, Martin H , Sanborn, Allen F , Phillips, P K
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6892 , http://hdl.handle.net/10962/d1011652 , http://dx.doi.org/10.1139/z03-119
- Description: Cicadas use acoustic signals to find mates and therefore offer a phylogenetically independent opportunity to test the generality of ideas about acoustic communication that were developed from studies of other animals. Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae) is a forest-dwelling platypleurine cicada that uses its calling song to form choruses and attract mates. Additionally, P. semiclara produces an encounter call that is involved in courtship and also in spacing males within choruses. Males generally call from exposed trunks and branches within the understory but clear of the undergrowth and fight with other males that call within about 50 cm of them. Choruses sing sporadically throughout the day but focus most of their calling activity into half-hour bouts at dawn and dusk. Body size and ambient temperature had no significant effect on spectral or temporal characteristics of the calling song. Body temperature measurements indicate that P. semiclara thermoregulates endothermically, with a body temperature of more than 22 °C above ambient temperature being measured during calling activity at dusk. Such endothermy provides an advantage to the cicadas by allowing them to call during crepuscular hours when atmospheric conditions are most optimal for acoustic communication and predation risks are minimal. Coincidentally, endogenously regulating body temperature allows the temporal characteristics of the call to be unaffected by ambient temperature changes.
- Full Text:
- Date Issued: 2003
- Authors: Villet, Martin H , Sanborn, Allen F , Phillips, P K
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6892 , http://hdl.handle.net/10962/d1011652 , http://dx.doi.org/10.1139/z03-119
- Description: Cicadas use acoustic signals to find mates and therefore offer a phylogenetically independent opportunity to test the generality of ideas about acoustic communication that were developed from studies of other animals. Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae) is a forest-dwelling platypleurine cicada that uses its calling song to form choruses and attract mates. Additionally, P. semiclara produces an encounter call that is involved in courtship and also in spacing males within choruses. Males generally call from exposed trunks and branches within the understory but clear of the undergrowth and fight with other males that call within about 50 cm of them. Choruses sing sporadically throughout the day but focus most of their calling activity into half-hour bouts at dawn and dusk. Body size and ambient temperature had no significant effect on spectral or temporal characteristics of the calling song. Body temperature measurements indicate that P. semiclara thermoregulates endothermically, with a body temperature of more than 22 °C above ambient temperature being measured during calling activity at dusk. Such endothermy provides an advantage to the cicadas by allowing them to call during crepuscular hours when atmospheric conditions are most optimal for acoustic communication and predation risks are minimal. Coincidentally, endogenously regulating body temperature allows the temporal characteristics of the call to be unaffected by ambient temperature changes.
- Full Text:
- Date Issued: 2003
Review of South African research on volcanic and related rocks and mantle-derived materials : 1999-2002
- Authors: Marsh, Julian S
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6737 , http://hdl.handle.net/10962/d1007550
- Description: This report reviews South African research relating to the scientific interests of the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) and which was published between 1999 and 2002. The focus is on published work and does not include conference presentations and abstract volumes or other informal documents.
- Full Text:
- Date Issued: 2003
- Authors: Marsh, Julian S
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6737 , http://hdl.handle.net/10962/d1007550
- Description: This report reviews South African research relating to the scientific interests of the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) and which was published between 1999 and 2002. The focus is on published work and does not include conference presentations and abstract volumes or other informal documents.
- Full Text:
- Date Issued: 2003
The biogeography of the Prosopistomatidae, with a particular emphasis on Southern African species
- Authors: Barber-James, Helen M
- Date: 2003
- Language: English
- Type: Conference paper
- Identifier: vital:6998 , http://hdl.handle.net/10962/d1008378
- Description: The mayfly family Prosopistomatidae consists of the single genus Prosopistoma Latreille. Its known distribution includes species from Africa, Madagascar, the Comores, Europe, the Levant, India, Sri Lanka, China, Vietnam, the Philippines, Malaysia, Sumatra, Java, the Solomon Islands, Papua New Guinea and northern Australia. A tropical Gondwanaland origin of the family has been suggested. No species are currently known from the Neotropical or Nearctic regions, though the family may yet be discovered in northeastern South America, since this region separated from West Africa only c.120 mya. Focussing on southern Africa, several undescribed species have recently been discovered, with interesting implications to the biogeography on a more localised scale. In the western Cape, a prosopistomatid species has been collected in the Olifants River, extending the distribution of this family further south into a more temperate region. Geological evidence indicates that the Olifants River was connected to the Orange River during the Tertiary period. Prosopistomatidae are known from the Orange River today, and the presence of the family in the Olifants River in the western Cape supports the geological evidence of the historical link between these two rivers. Another unexpected discovery was from the Buffalo River in the eastern Cape, at 33ºS. A subtropical zone extends along the east coast of South Africa as a result of the warm Agulhas current offshore, allowing the southerly extension of the distribution of more tropical species. , Research Update on Ephemeroptera & Plecoptera: Proceedings of the Tenth International Conference on Ephemeroptera, 8-11 August 2001, Perugia, Italy. University of Perugia, Perugia, Italy, pp. 263-270.
- Full Text:
- Date Issued: 2003
- Authors: Barber-James, Helen M
- Date: 2003
- Language: English
- Type: Conference paper
- Identifier: vital:6998 , http://hdl.handle.net/10962/d1008378
- Description: The mayfly family Prosopistomatidae consists of the single genus Prosopistoma Latreille. Its known distribution includes species from Africa, Madagascar, the Comores, Europe, the Levant, India, Sri Lanka, China, Vietnam, the Philippines, Malaysia, Sumatra, Java, the Solomon Islands, Papua New Guinea and northern Australia. A tropical Gondwanaland origin of the family has been suggested. No species are currently known from the Neotropical or Nearctic regions, though the family may yet be discovered in northeastern South America, since this region separated from West Africa only c.120 mya. Focussing on southern Africa, several undescribed species have recently been discovered, with interesting implications to the biogeography on a more localised scale. In the western Cape, a prosopistomatid species has been collected in the Olifants River, extending the distribution of this family further south into a more temperate region. Geological evidence indicates that the Olifants River was connected to the Orange River during the Tertiary period. Prosopistomatidae are known from the Orange River today, and the presence of the family in the Olifants River in the western Cape supports the geological evidence of the historical link between these two rivers. Another unexpected discovery was from the Buffalo River in the eastern Cape, at 33ºS. A subtropical zone extends along the east coast of South Africa as a result of the warm Agulhas current offshore, allowing the southerly extension of the distribution of more tropical species. , Research Update on Ephemeroptera & Plecoptera: Proceedings of the Tenth International Conference on Ephemeroptera, 8-11 August 2001, Perugia, Italy. University of Perugia, Perugia, Italy, pp. 263-270.
- Full Text:
- Date Issued: 2003
The influence of education on the interpretation of pharmaceutical pictograms for communicating medicine instructions:
- Dowse, Roslind, Ehlers, Martina S
- Authors: Dowse, Roslind , Ehlers, Martina S
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157014 , vital:40079 , DOI 10.1211/002235702810
- Description: To assess the influence of formal education on the interpretation of pharmaceutical pictograms.
- Full Text:
- Date Issued: 2003
- Authors: Dowse, Roslind , Ehlers, Martina S
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157014 , vital:40079 , DOI 10.1211/002235702810
- Description: To assess the influence of formal education on the interpretation of pharmaceutical pictograms.
- Full Text:
- Date Issued: 2003
Thermal responses in some Eastern Cape African Cicadas (Hemiptera: Cicadidae)
- Sanborn, Allen F, Phillips, P K, Villet, Martin H
- Authors: Sanborn, Allen F , Phillips, P K , Villet, Martin H
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6918 , http://hdl.handle.net/10962/d1011881
- Description: Thermal responses were measured in cicadas collected in the Eastern Cape Province of South Africa. The thermal responses of 22 species from 5 biomes were determined. Shade-seeking temperature was the most variable and related to the various biomes. Mean shade-seeking temperature was greatest for species inhabiting the thicket biome and lowest for species inhabiting the forest biome. The animals that live in the thicket biome may adapt to the greater thermal stress to take advantage of a habitat that permits lower predation pressure. There is a correlation between body size and shade-seeking temperatures with smaller species exhibiting lower thermal responses within a particular habitat. This may be related to the greater heat exchange in smaller species. Heat torpor temperatures did not differ between the various biomes.
- Full Text:
- Date Issued: 2003
- Authors: Sanborn, Allen F , Phillips, P K , Villet, Martin H
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6918 , http://hdl.handle.net/10962/d1011881
- Description: Thermal responses were measured in cicadas collected in the Eastern Cape Province of South Africa. The thermal responses of 22 species from 5 biomes were determined. Shade-seeking temperature was the most variable and related to the various biomes. Mean shade-seeking temperature was greatest for species inhabiting the thicket biome and lowest for species inhabiting the forest biome. The animals that live in the thicket biome may adapt to the greater thermal stress to take advantage of a habitat that permits lower predation pressure. There is a correlation between body size and shade-seeking temperatures with smaller species exhibiting lower thermal responses within a particular habitat. This may be related to the greater heat exchange in smaller species. Heat torpor temperatures did not differ between the various biomes.
- Full Text:
- Date Issued: 2003
Those merry, tinkling, tuneful bells : handbells in Victorian Grahamstown with a note on bell ringing at Grahamstown Cathedral
- Authors: Berning, J M
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6993 , http://hdl.handle.net/10962/d1012420
- Description: [From the introduction]: The idea of using sets of small bells tuned to particular notes in order to produce music is very old. There are illustrations of slung bells being played in this way from the 11th and 12th centuries. Bell ringers in England date the sue of sets of tuned and hand-held bells from as early as the 16th century though it seems that the modern handbell may have come into existence in the early 18th century. Such bells were used by tower bell ringers as convenient practice devices for change ringing. The ringing of tunes on handbells became popular in the 18th century and reached its heyday in the latter half of the 19th century. In England tune ringing was especially popular in the north and major competitions had their centre at Manchester. Special trains were run to competitions there and bands, ringing up to 200 bells, could find their skills tested on extracts from Mozart's Don Giovanni. World War I and the spread of alternative media of entertainment like radio put an end to ringing on this scale. , This publication marked the 150th Anniversary of the Diocese of Grahamstown. Michael Berning was a member of the Rhodes University Library staff from 1965 until his retirement in 1997. He was Tower Captain of the Grahamstown Cathedral during the 1980s.
- Full Text:
- Date Issued: 2003
- Authors: Berning, J M
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6993 , http://hdl.handle.net/10962/d1012420
- Description: [From the introduction]: The idea of using sets of small bells tuned to particular notes in order to produce music is very old. There are illustrations of slung bells being played in this way from the 11th and 12th centuries. Bell ringers in England date the sue of sets of tuned and hand-held bells from as early as the 16th century though it seems that the modern handbell may have come into existence in the early 18th century. Such bells were used by tower bell ringers as convenient practice devices for change ringing. The ringing of tunes on handbells became popular in the 18th century and reached its heyday in the latter half of the 19th century. In England tune ringing was especially popular in the north and major competitions had their centre at Manchester. Special trains were run to competitions there and bands, ringing up to 200 bells, could find their skills tested on extracts from Mozart's Don Giovanni. World War I and the spread of alternative media of entertainment like radio put an end to ringing on this scale. , This publication marked the 150th Anniversary of the Diocese of Grahamstown. Michael Berning was a member of the Rhodes University Library staff from 1965 until his retirement in 1997. He was Tower Captain of the Grahamstown Cathedral during the 1980s.
- Full Text:
- Date Issued: 2003
Water resources in Botswana with particular reference to the savanna regions
- du Plessis, A J E, Rowntree, Kate M
- Authors: du Plessis, A J E , Rowntree, Kate M
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6676 , http://hdl.handle.net/10962/d1006654
- Description: Production and development in the savanna regions of southern Africa are primarily determined by interactions between the limitations imposed by ecological determinants (such as rainfall and soil quality) and the management strategies of the specific region. Good planning, focussing on both the short and long-term effects of water use, is needed in water management strategies. Botswana is already experiencing so-called 'water stress' which is related to a number of factors such as rapidly increasing population leading to a sharp increase in water demand, low and variable rainfall, high rates of evaporation, and the high cost of exploiting existing water resources. At the current rates of abstraction, the lifetime of surface and groundwater resources is limited to decades. Botswana shares four river basins with its neighbouring countries. This results in a situation where 94% of the fresh water resources which Botswana can theoretically access originates outside its borders, making water resource management highly complex. Transnational sharing and management of water resources, therefore, plays a major role in securing sustainability of this precious resource.
- Full Text:
- Date Issued: 2003
- Authors: du Plessis, A J E , Rowntree, Kate M
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6676 , http://hdl.handle.net/10962/d1006654
- Description: Production and development in the savanna regions of southern Africa are primarily determined by interactions between the limitations imposed by ecological determinants (such as rainfall and soil quality) and the management strategies of the specific region. Good planning, focussing on both the short and long-term effects of water use, is needed in water management strategies. Botswana is already experiencing so-called 'water stress' which is related to a number of factors such as rapidly increasing population leading to a sharp increase in water demand, low and variable rainfall, high rates of evaporation, and the high cost of exploiting existing water resources. At the current rates of abstraction, the lifetime of surface and groundwater resources is limited to decades. Botswana shares four river basins with its neighbouring countries. This results in a situation where 94% of the fresh water resources which Botswana can theoretically access originates outside its borders, making water resource management highly complex. Transnational sharing and management of water resources, therefore, plays a major role in securing sustainability of this precious resource.
- Full Text:
- Date Issued: 2003
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