The relationship between female pupal mass and fecundity of Gratiana spadicea (Klug, 1829)(Coleoptera: Chrysomelidae)
- Czypionka, K, Hill, Martin P
- Authors: Czypionka, K , Hill, Martin P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451568 , vital:75060 , https://hdl.handle.net/10520/EJC32729
- Description: In the early 1900s Solanum sisymbriifolium Lamarck (Solanaceae), commonly known as dense thorned bitter apple and previously referred to as wild tomato, was introduced into southern Africa and has since become an invasive weed (Hill and Hulley 1995, 1996). In 1994 a chrysomelid beetle, Gratiana spadicea (Klug, 1829) (Coleoptera : Chrysomelidae), was introduced as a biological control agent against the weed (Hill and Hulley 1995). Prior to its release, various specificity tests were conducted to identify the potential host range of this agent. These included larval survival and adult choice and no-choice tests on several native and commercial Solanum species. These specificity tests generally identify the potential host range of an agent accurately, but fail to predict the magnitude of non-target risks in the field (Wan and Harris 1997; Louda et al. 2003).
- Full Text:
- Date Issued: 2007
- Authors: Czypionka, K , Hill, Martin P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451568 , vital:75060 , https://hdl.handle.net/10520/EJC32729
- Description: In the early 1900s Solanum sisymbriifolium Lamarck (Solanaceae), commonly known as dense thorned bitter apple and previously referred to as wild tomato, was introduced into southern Africa and has since become an invasive weed (Hill and Hulley 1995, 1996). In 1994 a chrysomelid beetle, Gratiana spadicea (Klug, 1829) (Coleoptera : Chrysomelidae), was introduced as a biological control agent against the weed (Hill and Hulley 1995). Prior to its release, various specificity tests were conducted to identify the potential host range of this agent. These included larval survival and adult choice and no-choice tests on several native and commercial Solanum species. These specificity tests generally identify the potential host range of an agent accurately, but fail to predict the magnitude of non-target risks in the field (Wan and Harris 1997; Louda et al. 2003).
- Full Text:
- Date Issued: 2007
The effect of water hyacinth, Eichhornia crassipes (Martius) SolmsLaubach (Pontederiaceae), on benthic biodiversity in two impoundments on the New Year's River, South Africa
- Midgley, John M, Hill, Martin P, Villet, Martin H
- Authors: Midgley, John M , Hill, Martin P , Villet, Martin H
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442358 , vital:73978 , https://doi.org/10.2989/16085910609503868
- Description: Water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae), forms thick mats that affect water resource utilisation, but little is known about its impacts on biodiversity in aquatic ecosystems. The benthic invertebrate community and algal biomass were sampled under water hyacinth mats and in water hyacinth-free water over a 13-month period, using artificial substrates in New Year's Dam, Eastern Cape Province, South Africa. The number of families per substrate (U = 796.5, P 0.001), number of individuals per substrate (U = 620.5, P 0.001), Shannon-Weiner Diversity Index (U = 1 038, P 0.001), Margalef's Richness index (U = 1 136, P 0.002), Pielou's Evenness Index (U = 1 230, P 0.001) and chlorophyll a (U = 678, P 0.01) were all significantly lower under water hyacinth mats than in water hyacinth-free zones. Similarly, multivariate analyses showed more diversity in invertebrate communities in open water than under water hyacinth. Thus, the control of water hyacinth is important, in order to prevent both ecological and economic impacts of biodiversity loss.
- Full Text:
- Date Issued: 2006
- Authors: Midgley, John M , Hill, Martin P , Villet, Martin H
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442358 , vital:73978 , https://doi.org/10.2989/16085910609503868
- Description: Water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae), forms thick mats that affect water resource utilisation, but little is known about its impacts on biodiversity in aquatic ecosystems. The benthic invertebrate community and algal biomass were sampled under water hyacinth mats and in water hyacinth-free water over a 13-month period, using artificial substrates in New Year's Dam, Eastern Cape Province, South Africa. The number of families per substrate (U = 796.5, P 0.001), number of individuals per substrate (U = 620.5, P 0.001), Shannon-Weiner Diversity Index (U = 1 038, P 0.001), Margalef's Richness index (U = 1 136, P 0.002), Pielou's Evenness Index (U = 1 230, P 0.001) and chlorophyll a (U = 678, P 0.01) were all significantly lower under water hyacinth mats than in water hyacinth-free zones. Similarly, multivariate analyses showed more diversity in invertebrate communities in open water than under water hyacinth. Thus, the control of water hyacinth is important, in order to prevent both ecological and economic impacts of biodiversity loss.
- Full Text:
- Date Issued: 2006
Glandular trichomes on the exotic Solanum sisymbriifolium Lamarck (Solanaceae): effective deterrents against an indigenous South African herbivore
- Hill, Martin P, Hulley, Patrick E, Allsopp, J, van Harmelen, G
- Authors: Hill, Martin P , Hulley, Patrick E , Allsopp, J , van Harmelen, G
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451413 , vital:75047 , https://hdl.handle.net/10520/AJA10213589_152
- Description: An examination of the leaves of several native and exotic Solanum species revealed that they all possessed glandular and non-glandular trichomes. The density of glandular trichomes was, however, very much lower on the leaves of the indigenous species than on the leaves of a weed species, Solanum sisymbriifolium Lamarck, and two other South American Solanum species. This difference could have contributed to the depauperate faunas supported by the exotic species. The morphology and behaviour of an indigenous Solanum-feeding tortoise beetle, Conchyloctenia tigrina Oliver (Coleoptera: Chrysomelidae), and a South American tortoise beetle, Gratiana spadicea (IQug) (Coleoptera: Chrysomelidae), were compared. The study revealed that while the exudate produced by the glandular trichomes afforded S. sisymbriifolium a level of resistance to C. tigrina, it is probably only one of the factors limiting the recruitment of indigenous herbivores onto S. sisymbriifolium.
- Full Text:
- Date Issued: 1997
- Authors: Hill, Martin P , Hulley, Patrick E , Allsopp, J , van Harmelen, G
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451413 , vital:75047 , https://hdl.handle.net/10520/AJA10213589_152
- Description: An examination of the leaves of several native and exotic Solanum species revealed that they all possessed glandular and non-glandular trichomes. The density of glandular trichomes was, however, very much lower on the leaves of the indigenous species than on the leaves of a weed species, Solanum sisymbriifolium Lamarck, and two other South American Solanum species. This difference could have contributed to the depauperate faunas supported by the exotic species. The morphology and behaviour of an indigenous Solanum-feeding tortoise beetle, Conchyloctenia tigrina Oliver (Coleoptera: Chrysomelidae), and a South American tortoise beetle, Gratiana spadicea (IQug) (Coleoptera: Chrysomelidae), were compared. The study revealed that while the exudate produced by the glandular trichomes afforded S. sisymbriifolium a level of resistance to C. tigrina, it is probably only one of the factors limiting the recruitment of indigenous herbivores onto S. sisymbriifolium.
- Full Text:
- Date Issued: 1997
Suitability of Metriona elatior (Klug)(Coleoptera: Chrysomelidae: Cassidinae) as a biological control agent for Solanum sisymbriifolium Lam.(Solanaceae).
- Hill, Martin P, Hulley, Patrick E
- Authors: Hill, Martin P , Hulley, Patrick E
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451540 , vital:75058 , https://hdl.handle.net/10520/AJA10213589_195
- Description: A leaf-feeding tortoise beetle, Metriona elatior (Klug), was screened as a biological control agent for the weed Solanum sisymbriifolium Lam. in South Africa. Favourable biological characteristics of M. elatior include a high reproductive capacity, long-lived adults and several generations per year under laboratory conditions. Host range was investigated by larval survival, and host plant choice tests by adults. Larvae were successfully reared on 10 of 11native Solanum species tested, five exotic Solanum species (except S. sisymbriifolium) and on the economically important eggplant, S. melongena L. The adult females selected these native and exotic Solanum species, and eggplant as suitable for oviposition. Based on these results it was decided not to apply for release of this insect.
- Full Text:
- Date Issued: 1996
- Authors: Hill, Martin P , Hulley, Patrick E
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451540 , vital:75058 , https://hdl.handle.net/10520/AJA10213589_195
- Description: A leaf-feeding tortoise beetle, Metriona elatior (Klug), was screened as a biological control agent for the weed Solanum sisymbriifolium Lam. in South Africa. Favourable biological characteristics of M. elatior include a high reproductive capacity, long-lived adults and several generations per year under laboratory conditions. Host range was investigated by larval survival, and host plant choice tests by adults. Larvae were successfully reared on 10 of 11native Solanum species tested, five exotic Solanum species (except S. sisymbriifolium) and on the economically important eggplant, S. melongena L. The adult females selected these native and exotic Solanum species, and eggplant as suitable for oviposition. Based on these results it was decided not to apply for release of this insect.
- Full Text:
- Date Issued: 1996
Insect herbivores associated with indigenous species of Solanum (Solanaceae) in the Transvaal, South Africa, and in Namibia
- Olckers, T, Hulley, Patrick E, Hill, Martin P
- Authors: Olckers, T , Hulley, Patrick E , Hill, Martin P
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451440 , vital:75049 , https://hdl.handle.net/10520/AJA10213589_108
- Description: Several indigenous Solanum (Solanaceae) species were surveyed in the Transvaal and Namibia as part of a broader study of the insect herbivores associated with indigenous, as well as weedy and cultivated exotic, solanurns in southern Africa. Insects were collected on three Solanum species in the Transvaal and on 10 in Namibia. Solanum panduriforme E. Mey. and S. incanum L. were abundant in both regions, while S. capense L. was the most common species in Namibia. These three Solanum species supported an abundance of insect herbivores, which included many oligophages found on solanurns in other regions of South Africa. Most of the Solanum insect species were found on a wide range of host plants, in a variety of habitats and under various climatic conditions.
- Full Text:
- Date Issued: 1995
- Authors: Olckers, T , Hulley, Patrick E , Hill, Martin P
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451440 , vital:75049 , https://hdl.handle.net/10520/AJA10213589_108
- Description: Several indigenous Solanum (Solanaceae) species were surveyed in the Transvaal and Namibia as part of a broader study of the insect herbivores associated with indigenous, as well as weedy and cultivated exotic, solanurns in southern Africa. Insects were collected on three Solanum species in the Transvaal and on 10 in Namibia. Solanum panduriforme E. Mey. and S. incanum L. were abundant in both regions, while S. capense L. was the most common species in Namibia. These three Solanum species supported an abundance of insect herbivores, which included many oligophages found on solanurns in other regions of South Africa. Most of the Solanum insect species were found on a wide range of host plants, in a variety of habitats and under various climatic conditions.
- Full Text:
- Date Issued: 1995
Insect herbivores on the exotic weeds Solanum elaeagnifolium Cavanilles and S. sisymbriifolium Lamarck (Solanaceae) in South Africa
- Hill, Martin P, Hulley, Patrick E, Olckers, T
- Authors: Hill, Martin P , Hulley, Patrick E , Olckers, T
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451454 , vital:75050 , https://hdl.handle.net/10520/AJA10213589_58
- Description: In South Africa, the weeds Solanum elaeagnifolium Cavanilles and S. sisymbriifolium Lamarck (Solanaceae) sustain little observable damage from herbivorous insects. Relatively few insect species occur on these plants and at low individual densities. Since native insects are not important in the natural control of S. elaeagnifolium and S. sisymbriifolium, additional agents should be imported for the biological control of these weeds. The absence of important local herbivores means that the possibility of interaction between these and potential biological control agents need not be a consideration in choosing the agents. The nature and numbers of the insect herbivores of S. elaeagnifolium and S. sisymbriifolium are compared with those on another solanaceous weed, S. mauritianum Scopoli, and on native Solanum species. These insect species are discussed relative to plant defence mechanisms.
- Full Text:
- Date Issued: 1993
- Authors: Hill, Martin P , Hulley, Patrick E , Olckers, T
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451454 , vital:75050 , https://hdl.handle.net/10520/AJA10213589_58
- Description: In South Africa, the weeds Solanum elaeagnifolium Cavanilles and S. sisymbriifolium Lamarck (Solanaceae) sustain little observable damage from herbivorous insects. Relatively few insect species occur on these plants and at low individual densities. Since native insects are not important in the natural control of S. elaeagnifolium and S. sisymbriifolium, additional agents should be imported for the biological control of these weeds. The absence of important local herbivores means that the possibility of interaction between these and potential biological control agents need not be a consideration in choosing the agents. The nature and numbers of the insect herbivores of S. elaeagnifolium and S. sisymbriifolium are compared with those on another solanaceous weed, S. mauritianum Scopoli, and on native Solanum species. These insect species are discussed relative to plant defence mechanisms.
- Full Text:
- Date Issued: 1993