Optimising design and effort for environmental surveys using dung beetles (Coleoptera: Scarabaeidae):
- Tocco, Claudia, Quinn, Danielle, Midgley, John M, Villet, Martin H
- Authors: Tocco, Claudia , Quinn, Danielle , Midgley, John M , Villet, Martin H
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140670 , vital:37908 , DOI: 10.4039/tce.2016.48
- Description: In biological monitoring, deploying an effective standardised quantitative sampling method, optimised by trap design and sampling effort, is an essential consideration. To exemplify this using dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae and Aphodiinae) communities, three pitfall trap designs (un-baited (TN), baited at ground level (flat trap, TF), and baited above the trap (hanging trap, TH)), employed with varying levels of sampling effort (number of traps = 1, 2, 3… 10; number of days = 1, 2, 3), were evaluated for sampling completeness and efficiency in the Eastern Cape, South Africa. Modelling and resampling simulation approaches were used to suggest optimal sampling protocols across environmentally diverse sites. Overall, TF recovered the greatest abundance and species richness of dung beetles, but behavioural guilds showed conflicting trends: endocoprids preferred TH while paracoprids and telocoprids preferred TF. Resampling simulation of trap type and the two components of sampling effort suggested that six TF traps left for three days was most efficient in obtaining a representative sample and allowed differentiation between trap types, allowing the improved efficiency to be recognised. The effect of trap type on non-target specimens, particularly ants, was also investigated. TF and TH caught almost no by-catch, which is ethically desirable.
- Full Text:
- Date Issued: 2016
- Authors: Tocco, Claudia , Quinn, Danielle , Midgley, John M , Villet, Martin H
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140670 , vital:37908 , DOI: 10.4039/tce.2016.48
- Description: In biological monitoring, deploying an effective standardised quantitative sampling method, optimised by trap design and sampling effort, is an essential consideration. To exemplify this using dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae and Aphodiinae) communities, three pitfall trap designs (un-baited (TN), baited at ground level (flat trap, TF), and baited above the trap (hanging trap, TH)), employed with varying levels of sampling effort (number of traps = 1, 2, 3… 10; number of days = 1, 2, 3), were evaluated for sampling completeness and efficiency in the Eastern Cape, South Africa. Modelling and resampling simulation approaches were used to suggest optimal sampling protocols across environmentally diverse sites. Overall, TF recovered the greatest abundance and species richness of dung beetles, but behavioural guilds showed conflicting trends: endocoprids preferred TH while paracoprids and telocoprids preferred TF. Resampling simulation of trap type and the two components of sampling effort suggested that six TF traps left for three days was most efficient in obtaining a representative sample and allowed differentiation between trap types, allowing the improved efficiency to be recognised. The effect of trap type on non-target specimens, particularly ants, was also investigated. TF and TH caught almost no by-catch, which is ethically desirable.
- Full Text:
- Date Issued: 2016
Predicting geographic distribution of seven blowfly species (Diptera: Calliphoridae) in South Africa
- Richards, C S, Williams, K A, Villet, Martin H
- Authors: Richards, C S , Williams, K A , Villet, Martin H
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6854 , http://hdl.handle.net/10962/d1011135
- Description: The predicted geographic distributions of seven forensically important blowfly species are modelled using the computer program Maxent, based on selected climatic variables for South Africa, a country with large climatic and environmental gradients. It is shown that although temperature was hypothesized to most influence the distributions of these ectotherms, moisture, and particularly humidity, was in fact usually paramount. Chrysomya albiceps (Wiedemann) and C. marginalis (Robineau-Desvoidy) had the most widespread geographic and climatic distribution, while the forest-associated C. inclinata(Walker) was the least widespread. Chrysomya putoria (Wiedemann) and C. megacephala (Fabricius) had very similar predicted distributions that were restricted mainly to Limpopo, Mpumalanga, KwaZulu-Natal and the coast of the Eastern Cape. Chrysomya chloropyga (Wiedemann) and Calliphora croceipalpis (Jaennicke) were the only species predicted to occur at high altitudes. Blowfly distributions restricted to part of the map area were predicted better than those that were more widespread in the region, presumably because species with extremely widespread distributions in a study area occupy nearly the whole range of variation of most predictor variables, leaving little variation with which themaximumentropy modelling method can discriminate between presence and absence of the organism.
- Full Text:
- Date Issued: 2009
Predicting geographic distribution of seven blowfly species (Diptera: Calliphoridae) in South Africa
- Authors: Richards, C S , Williams, K A , Villet, Martin H
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6854 , http://hdl.handle.net/10962/d1011135
- Description: The predicted geographic distributions of seven forensically important blowfly species are modelled using the computer program Maxent, based on selected climatic variables for South Africa, a country with large climatic and environmental gradients. It is shown that although temperature was hypothesized to most influence the distributions of these ectotherms, moisture, and particularly humidity, was in fact usually paramount. Chrysomya albiceps (Wiedemann) and C. marginalis (Robineau-Desvoidy) had the most widespread geographic and climatic distribution, while the forest-associated C. inclinata(Walker) was the least widespread. Chrysomya putoria (Wiedemann) and C. megacephala (Fabricius) had very similar predicted distributions that were restricted mainly to Limpopo, Mpumalanga, KwaZulu-Natal and the coast of the Eastern Cape. Chrysomya chloropyga (Wiedemann) and Calliphora croceipalpis (Jaennicke) were the only species predicted to occur at high altitudes. Blowfly distributions restricted to part of the map area were predicted better than those that were more widespread in the region, presumably because species with extremely widespread distributions in a study area occupy nearly the whole range of variation of most predictor variables, leaving little variation with which themaximumentropy modelling method can discriminate between presence and absence of the organism.
- Full Text:
- Date Issued: 2009
Spermiogenesis in three species of cicadas (Hemiptera: Cicadidae)
- Chawanji, A S, Hodgson, Alan N, Villet, Martin H, Sanborn, Allen F, Phillips, P K
- Authors: Chawanji, A S , Hodgson, Alan N , Villet, Martin H , Sanborn, Allen F , Phillips, P K
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6865 , http://hdl.handle.net/10962/d1011207
- Description: Spermiogenesis in three species of cicadas representing one cicadettine (Monomatapa matoposa Boulard) and two cicadines (Diceroprocta biconica [Walker] and Kongota punctigera [Walker]) was investigated by light and electron microscopy. Although spermiogenesis was occurring in the testis of adult males of all species, earlier spermiogenic stages were observed in D. biconica only. While spermiogenesis was similar to that described for other insects, some differences were noted. For example granular material did not assemble around the centriole to form a centriolar adjunct but did accumulate in the cytoplasm of early spermatids adjacent to a region of the nuclear membrane where nuclear pores were aggregated. In late spermatids this material accumulated anterior to the mitochondrial derivatives in a developing postero-lateral nuclear groove. While this material has been named the ‘centriolar adjunct’ by previous authors, its formation away from the centriole raises questions about its true identity. Second, during acrosome maturation an ante-acrosomal region of cytoplasm develops. Although present in later spermatids, this region is lost in spermatozoa. Interspecific variations in chromatin condensation patterns and the number of microtubule layers encircling the spermatid nucleus during spermiogenesis were noted.
- Full Text:
- Date Issued: 2007
- Authors: Chawanji, A S , Hodgson, Alan N , Villet, Martin H , Sanborn, Allen F , Phillips, P K
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6865 , http://hdl.handle.net/10962/d1011207
- Description: Spermiogenesis in three species of cicadas representing one cicadettine (Monomatapa matoposa Boulard) and two cicadines (Diceroprocta biconica [Walker] and Kongota punctigera [Walker]) was investigated by light and electron microscopy. Although spermiogenesis was occurring in the testis of adult males of all species, earlier spermiogenic stages were observed in D. biconica only. While spermiogenesis was similar to that described for other insects, some differences were noted. For example granular material did not assemble around the centriole to form a centriolar adjunct but did accumulate in the cytoplasm of early spermatids adjacent to a region of the nuclear membrane where nuclear pores were aggregated. In late spermatids this material accumulated anterior to the mitochondrial derivatives in a developing postero-lateral nuclear groove. While this material has been named the ‘centriolar adjunct’ by previous authors, its formation away from the centriole raises questions about its true identity. Second, during acrosome maturation an ante-acrosomal region of cytoplasm develops. Although present in later spermatids, this region is lost in spermatozoa. Interspecific variations in chromatin condensation patterns and the number of microtubule layers encircling the spermatid nucleus during spermiogenesis were noted.
- Full Text:
- Date Issued: 2007
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