Pigs vs people: the use of pigs as analogues for humans in forensic entomology and taphonomy research
- Matuszewski, Szymon, Hall, Martin J R, Moreau, Gaétan, Schoenly, Kenneth G, Tarone, Aaron M, Villet, Martin H
- Authors: Matuszewski, Szymon , Hall, Martin J R , Moreau, Gaétan , Schoenly, Kenneth G , Tarone, Aaron M , Villet, Martin H
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140557 , vital:37898 , DOI: 10.1007/s00414-019-02074-5
- Description: Most studies of decomposition in forensic entomology and taphonomy have used non-human cadavers. Following the recommendation of using domestic pig cadavers as analogues for humans in forensic entomology in the 1980s, pigs became the most frequently used model cadavers in forensic sciences. They have shaped our understanding of how large vertebrate cadavers decompose in, for example, various environments, seasons and after various ante- or postmortem cadaver modifications. They have also been used to demonstrate the feasibility of several new or well-established forensic techniques. The advent of outdoor human taphonomy facilities enabled experimental comparisons of decomposition between pig and human cadavers. Recent comparisons challenged the pig-as-analogue claim in entomology and taphonomy research. In this review, we discuss in a broad methodological context the advantages and disadvantages of pig and human cadavers for forensic research and rebut the critique of pigs as analogues for humans. We conclude that experiments using human cadaver analogues (i.e. pig carcasses) are easier to replicate and more practical for controlling confounding factors than studies based solely on humans and, therefore, are likely to remain our primary epistemic source of forensic knowledge for the immediate future. We supplement these considerations with new guidelines for model cadaver choice in forensic science research.
- Full Text:
- Date Issued: 2019
- Authors: Matuszewski, Szymon , Hall, Martin J R , Moreau, Gaétan , Schoenly, Kenneth G , Tarone, Aaron M , Villet, Martin H
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140557 , vital:37898 , DOI: 10.1007/s00414-019-02074-5
- Description: Most studies of decomposition in forensic entomology and taphonomy have used non-human cadavers. Following the recommendation of using domestic pig cadavers as analogues for humans in forensic entomology in the 1980s, pigs became the most frequently used model cadavers in forensic sciences. They have shaped our understanding of how large vertebrate cadavers decompose in, for example, various environments, seasons and after various ante- or postmortem cadaver modifications. They have also been used to demonstrate the feasibility of several new or well-established forensic techniques. The advent of outdoor human taphonomy facilities enabled experimental comparisons of decomposition between pig and human cadavers. Recent comparisons challenged the pig-as-analogue claim in entomology and taphonomy research. In this review, we discuss in a broad methodological context the advantages and disadvantages of pig and human cadavers for forensic research and rebut the critique of pigs as analogues for humans. We conclude that experiments using human cadaver analogues (i.e. pig carcasses) are easier to replicate and more practical for controlling confounding factors than studies based solely on humans and, therefore, are likely to remain our primary epistemic source of forensic knowledge for the immediate future. We supplement these considerations with new guidelines for model cadaver choice in forensic science research.
- Full Text:
- Date Issued: 2019
A global study of forensically significant calliphorids: implications for identification
- Harvey, M L, Gaudieri, S, Villet, Martin H, Dadour, I R
- Authors: Harvey, M L , Gaudieri, S , Villet, Martin H , Dadour, I R
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6863 , http://hdl.handle.net/10962/d1011156
- Description: A proliferation of molecular studies of the forensically significant Calliphoridae in the last decade has seen molecule-based identification of immature and damaged specimens become a routine complement to traditional morphological identification as a preliminary to the accurate estimation of post-mortem intervals (PMI), which depends on the use of species-specific developmental data. Published molecular studies have tended to focus on generating data for geographically localised communities of species of importance, which has limited the consideration of intraspecific variation in species of global distribution. This study used phylogenetic analysis to assess the species status of 27 forensically important calliphorid species based on 1167 base pairs of the COI gene of 119 specimens from 22 countries, and confirmed the utility of the COI gene in identifying most species. The species Lucilia cuprina, Chrysomya megacephala, Ch. saffranea, Ch. albifrontalis and Calliphora stygia were unable to be monophyletically resolved based on these data. Identification of phylogenetically young species will require a faster-evolving molecular marker, but most species could be unambiguously characterised by sampling relatively few conspecific individuals if they were from distant localities. Intraspecific geographical variation was observed within Ch. rufifacies and L. cuprina, and is discussed with reference to unrecognised species.
- Full Text:
- Date Issued: 2008
- Authors: Harvey, M L , Gaudieri, S , Villet, Martin H , Dadour, I R
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6863 , http://hdl.handle.net/10962/d1011156
- Description: A proliferation of molecular studies of the forensically significant Calliphoridae in the last decade has seen molecule-based identification of immature and damaged specimens become a routine complement to traditional morphological identification as a preliminary to the accurate estimation of post-mortem intervals (PMI), which depends on the use of species-specific developmental data. Published molecular studies have tended to focus on generating data for geographically localised communities of species of importance, which has limited the consideration of intraspecific variation in species of global distribution. This study used phylogenetic analysis to assess the species status of 27 forensically important calliphorid species based on 1167 base pairs of the COI gene of 119 specimens from 22 countries, and confirmed the utility of the COI gene in identifying most species. The species Lucilia cuprina, Chrysomya megacephala, Ch. saffranea, Ch. albifrontalis and Calliphora stygia were unable to be monophyletically resolved based on these data. Identification of phylogenetically young species will require a faster-evolving molecular marker, but most species could be unambiguously characterised by sampling relatively few conspecific individuals if they were from distant localities. Intraspecific geographical variation was observed within Ch. rufifacies and L. cuprina, and is discussed with reference to unrecognised species.
- Full Text:
- Date Issued: 2008
A history of southern African research relevant to forensic entomology
- Williams, K A, Villet, Martin H
- Authors: Williams, K A , Villet, Martin H
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6909 , http://hdl.handle.net/10962/d1011862
- Description: Entomological forensic evidence has been used in southern Africa for decades but explicitly forensic research began in southern Africa only 26 years ago. Although applicable local research has accumulated since 1921, it is scattered in a diverse literature or unpublished. Some overseas research has also touched on local species. This review uses a historical approach to synthesize the southern African literature and to illustrate the cross-disciplinary, opportunistic nature of forensic entomology. Distinct phases of research focused on agriculture (1921-1950), medicine (1952- 1965), ecology (1968-1990) and forensics (1980-2005), but systematics spanned the entire period and tended to be ad hoc. Few scientists were involved, situated at geographically distant locations and with widely disparate research interests. The review concludes with an overview of southern African entomologists who have been involved in medico-legal investigations, and a critical evaluation of the past and future of the discipline locally.
- Full Text:
- Date Issued: 2006
- Authors: Williams, K A , Villet, Martin H
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6909 , http://hdl.handle.net/10962/d1011862
- Description: Entomological forensic evidence has been used in southern Africa for decades but explicitly forensic research began in southern Africa only 26 years ago. Although applicable local research has accumulated since 1921, it is scattered in a diverse literature or unpublished. Some overseas research has also touched on local species. This review uses a historical approach to synthesize the southern African literature and to illustrate the cross-disciplinary, opportunistic nature of forensic entomology. Distinct phases of research focused on agriculture (1921-1950), medicine (1952- 1965), ecology (1968-1990) and forensics (1980-2005), but systematics spanned the entire period and tended to be ad hoc. Few scientists were involved, situated at geographically distant locations and with widely disparate research interests. The review concludes with an overview of southern African entomologists who have been involved in medico-legal investigations, and a critical evaluation of the past and future of the discipline locally.
- Full Text:
- Date Issued: 2006
Molecular phylogeny of Chondrocyclus (Gastropoda: Cyclophoridae), a widespread genus of sedentary, restricted-range snails:
- Cole, Mary L, Raheem, Dinarzarde C, Villet, Martin H
- Authors: Cole, Mary L , Raheem, Dinarzarde C , Villet, Martin H
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140761 , vital:37916 , DOI: 10.1016/j.ympev.2018.09.018
- Description: The genus Chondrocyclus Ancey, 1898 contains the majority of southern African members of the Cyclophoridae, a large family of operculate land snails. We present the first molecular phylogeny of the genus based on two mitochondrial genes (16S and CO1) and complement this with an appraisal of morphological characters relating to the shell and soft parts. Worn shells on which some descriptions and records of different species were based appear to be indistinguishable morphologically, creating taxonomic confusion. We show that Chondrocyclus s.l. underwent two major radiations, one Afromontane and the other largely coastal.
- Full Text:
- Date Issued: 2019
- Authors: Cole, Mary L , Raheem, Dinarzarde C , Villet, Martin H
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140761 , vital:37916 , DOI: 10.1016/j.ympev.2018.09.018
- Description: The genus Chondrocyclus Ancey, 1898 contains the majority of southern African members of the Cyclophoridae, a large family of operculate land snails. We present the first molecular phylogeny of the genus based on two mitochondrial genes (16S and CO1) and complement this with an appraisal of morphological characters relating to the shell and soft parts. Worn shells on which some descriptions and records of different species were based appear to be indistinguishable morphologically, creating taxonomic confusion. We show that Chondrocyclus s.l. underwent two major radiations, one Afromontane and the other largely coastal.
- Full Text:
- Date Issued: 2019
Trophic preference of southern African dung beetles (Scarabaeoidea: Scarabaeinae and Aphodiinae) and its influence on bioindicator surveys:
- Tocco, Claudia, Balmer, Jonathan P, Villet, Martin H
- Authors: Tocco, Claudia , Balmer, Jonathan P , Villet, Martin H
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140796 , vital:37919 , DOI: 10.1111/aje.12523
- Description: Environmental assessments using bioindicators gain value if the interpretability of the indicator used is high, and it is clear how survey methods affect survey comparisons. Because dung beetles are favoured as bioindicators, we studied the trophic preference of a southern African beetle community and its potential effects on surveys of beetle diversity using manual sampling of droppings and pitfall traps baited with carnivore, ruminant or nonruminant dung. Manual sampling showed no significant differences between dung types in either dung beetles abundance or species richness. Generalised linear mixed models of total and endocoprid abundances, species richness and Real Shannon index of trap samples showed higher dung beetle diversity associated with ruminant than with nonruminant dung, which in turn was significantly preferred over carnivore dung.
- Full Text:
- Date Issued: 2018
- Authors: Tocco, Claudia , Balmer, Jonathan P , Villet, Martin H
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140796 , vital:37919 , DOI: 10.1111/aje.12523
- Description: Environmental assessments using bioindicators gain value if the interpretability of the indicator used is high, and it is clear how survey methods affect survey comparisons. Because dung beetles are favoured as bioindicators, we studied the trophic preference of a southern African beetle community and its potential effects on surveys of beetle diversity using manual sampling of droppings and pitfall traps baited with carnivore, ruminant or nonruminant dung. Manual sampling showed no significant differences between dung types in either dung beetles abundance or species richness. Generalised linear mixed models of total and endocoprid abundances, species richness and Real Shannon index of trap samples showed higher dung beetle diversity associated with ruminant than with nonruminant dung, which in turn was significantly preferred over carnivore dung.
- Full Text:
- Date Issued: 2018
Larval development of the carrion-breeding flesh fly, Sarcophaga (Liosarcophaga) tibialis Macquart (Diptera: Sarcophagidae), at constant temperatures
- Villet, Martin H, MacKenzie, B, Muller, Wilhelmine J
- Authors: Villet, Martin H , MacKenzie, B , Muller, Wilhelmine J
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7091 , http://hdl.handle.net/10962/d1012422
- Description: Larvae of Sarcophaga (Liosarcophaga) tibialis Macquart were raised on chicken liver under six different constant temperatures. Maximum survival indicated an optimal developmental temperature of near 20°C, while trends in mortality, larval length and larval mass implied that the thermal window for successful development lay between 15°C and 30°C. Using a recently described method to estimate a simple thermal summation model, it was found that the timing of the end of the feeding phase could be estimated by a developmental zero (D0) of 5.2°C (S.E. = 1.21) and a thermal summation constant (K) of 106.4 d°C (S.E. = 8.31) and of the end of the wandering phase by D0 = 4.1°C (S.E. = 0.39) and K = 126.7 d°C (S.E. = 3.28). Published development times at constant temperatures were compiled for 19 other species of flesh flies, and the developmental constants were calculated for six species for which sufficient data were accumulated.
- Full Text:
- Date Issued: 2006
- Authors: Villet, Martin H , MacKenzie, B , Muller, Wilhelmine J
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7091 , http://hdl.handle.net/10962/d1012422
- Description: Larvae of Sarcophaga (Liosarcophaga) tibialis Macquart were raised on chicken liver under six different constant temperatures. Maximum survival indicated an optimal developmental temperature of near 20°C, while trends in mortality, larval length and larval mass implied that the thermal window for successful development lay between 15°C and 30°C. Using a recently described method to estimate a simple thermal summation model, it was found that the timing of the end of the feeding phase could be estimated by a developmental zero (D0) of 5.2°C (S.E. = 1.21) and a thermal summation constant (K) of 106.4 d°C (S.E. = 8.31) and of the end of the wandering phase by D0 = 4.1°C (S.E. = 0.39) and K = 126.7 d°C (S.E. = 3.28). Published development times at constant temperatures were compiled for 19 other species of flesh flies, and the developmental constants were calculated for six species for which sufficient data were accumulated.
- Full Text:
- Date Issued: 2006
Molecular identification of some forensically important blowflies of southern Africa and Australia
- Harvey, M L, Mansell, M W, Villet, Martin H, Dadour, I R
- Authors: Harvey, M L , Mansell, M W , Villet, Martin H , Dadour, I R
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6953 , http://hdl.handle.net/10962/d1011986
- Description: One major aspect of research in forensic entomology is the investigation of molecular techniques for the accurate identification of insects. Studies to date have addressed the corpse fauna of many geographical regions, but generally neglected the southern African calliphorid species. In this study, forensically significant calliphorids from South Africa, Swaziland, Botswana and Zimbabwe and Australia were sequenced over an 1167 base pair region of the COI gene. Phylogenetic analysis was performed to examine the ability of the region to resolve species identities and taxonomic relationships between species. Analyses by neighbour-joining, maximum parsimony and maximum likelihood methods all showed the potential of this region to provide the necessary species-level identifications for application to post-mortem interval (PMI) estimation; however, higher level taxonomic relationships did vary according to method of analysis. Intraspecific variation was also considered in relation to determining suitable maximum levels of variation to be expected during analysis. Individuals of some species in the study represented populations from both South Africa and the east coast of Australia, yet maximum intraspecific variation over this gene region was calculated at 0.8%, with minimum interspecific variation at 3%, indicating distinct ranges of variation to be expected at intra- and interspecific levels. This region therefore appears to provide southern African forensic entomologists with a new technique for providing accurate identification for application to estimation of PMI.
- Full Text:
- Date Issued: 2003
- Authors: Harvey, M L , Mansell, M W , Villet, Martin H , Dadour, I R
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6953 , http://hdl.handle.net/10962/d1011986
- Description: One major aspect of research in forensic entomology is the investigation of molecular techniques for the accurate identification of insects. Studies to date have addressed the corpse fauna of many geographical regions, but generally neglected the southern African calliphorid species. In this study, forensically significant calliphorids from South Africa, Swaziland, Botswana and Zimbabwe and Australia were sequenced over an 1167 base pair region of the COI gene. Phylogenetic analysis was performed to examine the ability of the region to resolve species identities and taxonomic relationships between species. Analyses by neighbour-joining, maximum parsimony and maximum likelihood methods all showed the potential of this region to provide the necessary species-level identifications for application to post-mortem interval (PMI) estimation; however, higher level taxonomic relationships did vary according to method of analysis. Intraspecific variation was also considered in relation to determining suitable maximum levels of variation to be expected during analysis. Individuals of some species in the study represented populations from both South Africa and the east coast of Australia, yet maximum intraspecific variation over this gene region was calculated at 0.8%, with minimum interspecific variation at 3%, indicating distinct ranges of variation to be expected at intra- and interspecific levels. This region therefore appears to provide southern African forensic entomologists with a new technique for providing accurate identification for application to estimation of PMI.
- 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
Preliminary observations on the effects of hydrocortisone and sodium methohexital on development of Sarcophaga (Curranea) tibialis Macquart (Diptera: Sarcophagidae), and implications for estimating post mortem interval
- Musvasva, E, Williams, K A, Muller, W J, Villet, Martin H
- Authors: Musvasva, E , Williams, K A , Muller, W J , Villet, Martin H
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:7075 , http://hdl.handle.net/10962/d1009532
- Description: Larvae of Sarcophaga (Curranea) tibialis (S. tibialis) were reared at constant temperature on chicken liver treated with a steroid or a barbiturate at concentrations that would be lethal, half-lethal and twice-lethal doses for humans. Trends to greater mortality at higher drug concentrations were not statistically significant. Larvae exposed to either drug took significantly longer to reach pupation compared to those in the control, while larvae exposed to sodium methohexital passed through pupation significantly faster than those in the control. No systematic relationship was found between drug concentration and development time of larvae or pupae. The total developmental period from hatching to eclosion did not differ between treatments, implying that estimates of post mortem intervals- (PMI) based on the emergence of adult flies will not be affected by the involvement of these drugs in a case. On the other hand, anomalous pupation spans may indicate the presence of barbiturates. These findings are compared with patterns found in another fly fed other contaminants.
- Full Text:
- Date Issued: 2001
- Authors: Musvasva, E , Williams, K A , Muller, W J , Villet, Martin H
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:7075 , http://hdl.handle.net/10962/d1009532
- Description: Larvae of Sarcophaga (Curranea) tibialis (S. tibialis) were reared at constant temperature on chicken liver treated with a steroid or a barbiturate at concentrations that would be lethal, half-lethal and twice-lethal doses for humans. Trends to greater mortality at higher drug concentrations were not statistically significant. Larvae exposed to either drug took significantly longer to reach pupation compared to those in the control, while larvae exposed to sodium methohexital passed through pupation significantly faster than those in the control. No systematic relationship was found between drug concentration and development time of larvae or pupae. The total developmental period from hatching to eclosion did not differ between treatments, implying that estimates of post mortem intervals- (PMI) based on the emergence of adult flies will not be affected by the involvement of these drugs in a case. On the other hand, anomalous pupation spans may indicate the presence of barbiturates. These findings are compared with patterns found in another fly fed other contaminants.
- Full Text:
- Date Issued: 2001
Analysis of the calling songs of Platypleura hirtipennis (Germar, 1834) and P. plumosa (Germar, 1834) (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:6896 , http://hdl.handle.net/10962/d1011656
- Description: [From the introduction]: Most male cicadas produce a calling song in order to attract conspecific females. These songs have been shown to differ in closely related species (e.g. Alexander & Moore 1962; Villet 1988, 1989; Boulard 1995; Marshall & Cooley 2000; Sanborn & Phillips 2001) and in species which share habitats (e.g. Sueur 2002). The former is an inevitable part of the divergence of recognition signals that characterizes the speciation process in animals using acoustic signals (Villet 1995), while the latter would be expected from a signal that acts as a reproductive isolating mechanism (Claridge 1985; Marshall & Cooley 2000). Calling songs are therefore of value in resolving taxonomic problems in the cicadas.
- Full Text:
- Date Issued: 2003
- Authors: Sanborn, Allen F , Phillips, P K , Villet, Martin H
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6896 , http://hdl.handle.net/10962/d1011656
- Description: [From the introduction]: Most male cicadas produce a calling song in order to attract conspecific females. These songs have been shown to differ in closely related species (e.g. Alexander & Moore 1962; Villet 1988, 1989; Boulard 1995; Marshall & Cooley 2000; Sanborn & Phillips 2001) and in species which share habitats (e.g. Sueur 2002). The former is an inevitable part of the divergence of recognition signals that characterizes the speciation process in animals using acoustic signals (Villet 1995), while the latter would be expected from a signal that acts as a reproductive isolating mechanism (Claridge 1985; Marshall & Cooley 2000). Calling songs are therefore of value in resolving taxonomic problems in the cicadas.
- Full Text:
- Date Issued: 2003
A fuzzy classification technique for predicting species' distributions: applications using invasive alien plants and indigenous insects
- Robertson, Mark P, Villet, Martin H, Palmer, Anthony R
- Authors: Robertson, Mark P , Villet, Martin H , Palmer, Anthony R
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6897 , http://hdl.handle.net/10962/d1011659 , http://dx.doi.org/10.1111/j.1366-9516.2004.00108.x
- Description: A new predictive modelling technique called the fuzzy envelope model (FEM) is introduced. The technique can be used to predict potential distributions of organisms using presence-only locality records and a set of environmental predictor variables. FEM uses fuzzy logic to classify a set of predictor variable maps based on the values associated with presence records and combines the results to produce a potential distribution map for a target species. This technique represents several refinements of the envelope approach used in the BIOCLIM modelling package. These refinements are related to the way in which FEMs deal with uncertainty, the way in which this uncertainty is represented in the resultant potential distribution maps, and the way that these maps can be interpreted and applied. To illustrate its potential use in biogeographical studies, FEM was applied to predicting the potential distribution of three invasive alien plant species (Lantana camara L., Ricinus communis L. and Solanum mauritianum Scop.), and three native cicada species (Capicada decora Germar, Platypleura deusta Thun. and P. capensis L.) in South Africa, Lesotho and Swaziland. These models were quantitatively compared with models produced by means of the algorithm used in the BIOCLIM modelling package, which is referred to as a crisp envelope model (the CEM design). The average performance of models of the FEM design was consistently higher than those of the CEM design. There were significant differences in model performance among species but there was no significant interaction between model design and species. The average maximum kappa value ranged from 0.70 to 0.90 for FEM design and from 0.57 to 0.89 for the CEM design, which can be described as 'good' to 'excellent' using published ranges of agreement for the kappa statistic. This technique can be used to predict species' potential distributions that could be used for identifying regions at risk from invasion by alien species. These predictions could also be used in conservation planning in the case of native species.
- Full Text:
- Date Issued: 2004
- Authors: Robertson, Mark P , Villet, Martin H , Palmer, Anthony R
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6897 , http://hdl.handle.net/10962/d1011659 , http://dx.doi.org/10.1111/j.1366-9516.2004.00108.x
- Description: A new predictive modelling technique called the fuzzy envelope model (FEM) is introduced. The technique can be used to predict potential distributions of organisms using presence-only locality records and a set of environmental predictor variables. FEM uses fuzzy logic to classify a set of predictor variable maps based on the values associated with presence records and combines the results to produce a potential distribution map for a target species. This technique represents several refinements of the envelope approach used in the BIOCLIM modelling package. These refinements are related to the way in which FEMs deal with uncertainty, the way in which this uncertainty is represented in the resultant potential distribution maps, and the way that these maps can be interpreted and applied. To illustrate its potential use in biogeographical studies, FEM was applied to predicting the potential distribution of three invasive alien plant species (Lantana camara L., Ricinus communis L. and Solanum mauritianum Scop.), and three native cicada species (Capicada decora Germar, Platypleura deusta Thun. and P. capensis L.) in South Africa, Lesotho and Swaziland. These models were quantitatively compared with models produced by means of the algorithm used in the BIOCLIM modelling package, which is referred to as a crisp envelope model (the CEM design). The average performance of models of the FEM design was consistently higher than those of the CEM design. There were significant differences in model performance among species but there was no significant interaction between model design and species. The average maximum kappa value ranged from 0.70 to 0.90 for FEM design and from 0.57 to 0.89 for the CEM design, which can be described as 'good' to 'excellent' using published ranges of agreement for the kappa statistic. This technique can be used to predict species' potential distributions that could be used for identifying regions at risk from invasion by alien species. These predictions could also be used in conservation planning in the case of native species.
- Full Text:
- Date Issued: 2004
“The Two Cultures reunited: entomology for everyone”
- Authors: Villet, Martin H
- Date: 2009
- Language: English
- Type: Audio , text
- Identifier: vital:587 , http://hdl.handle.net/10962/d1018947
- Description: Fifty years ago C.P. Snow delivered his essay, "The Two Cultures", sparking the schism between the Humanities and the Sciences. This lecture explores cultural entomology as a means of reconciling two other cultures: academia and society, and suggests one way of addressing this alienating dilemma.
- Full Text:
- Date Issued: 2009
- Authors: Villet, Martin H
- Date: 2009
- Language: English
- Type: Audio , text
- Identifier: vital:587 , http://hdl.handle.net/10962/d1018947
- Description: Fifty years ago C.P. Snow delivered his essay, "The Two Cultures", sparking the schism between the Humanities and the Sciences. This lecture explores cultural entomology as a means of reconciling two other cultures: academia and society, and suggests one way of addressing this alienating dilemma.
- Full Text:
- Date Issued: 2009
The uses of Chrysomya megacephala (Fabricius, 1794)(Diptera: Calliphoridae) in forensic entomology:
- Badenhorst, Rozane, Villet, Martin H
- Authors: Badenhorst, Rozane , Villet, Martin H
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140631 , vital:37905 , DOI: 10.1080/20961790.2018.1426136
- Description: Chrysomya megacephala (Fabricius, 1794) occurs on every continent and is closely associated with carrion and decaying material in human environments. Its abilities to find dead bodies and carry pathogens give it a prominence in human affairs that may involve prosecution or litigation, and therefore forensic entomologists. The identification, geographical distribution and biology of the species are reviewed to provide a background for approaches that four branches of forensic entomology (urban, stored-product, medico-criminal and environmental) might take to investigations involving this fly.
- Full Text:
- Date Issued: 2018
- Authors: Badenhorst, Rozane , Villet, Martin H
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140631 , vital:37905 , DOI: 10.1080/20961790.2018.1426136
- Description: Chrysomya megacephala (Fabricius, 1794) occurs on every continent and is closely associated with carrion and decaying material in human environments. Its abilities to find dead bodies and carry pathogens give it a prominence in human affairs that may involve prosecution or litigation, and therefore forensic entomologists. The identification, geographical distribution and biology of the species are reviewed to provide a background for approaches that four branches of forensic entomology (urban, stored-product, medico-criminal and environmental) might take to investigations involving this fly.
- Full Text:
- Date Issued: 2018
Bloodmeal analysis in Culicoides midges collected near horses, donkeys and zebras in the Eastern Cape, South Africa:
- Riddin, M A, Venter, G J, Labuschagne, K, Villet, Martin H
- Authors: Riddin, M A , Venter, G J , Labuschagne, K , Villet, Martin H
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140692 , vital:37910 , DOI: 10.1111/mve.12381
- Description: An upsurge in African horse sickness (AHS) in the Eastern Cape, South Africa, from 2006 led to an epidemiological reassessment of the disease there. Light trapping surveys carried out near horses, donkeys and zebras in 2014–2016 collected 39 species of Culicoides midge (Diptera: Ceratopogonidae) that are potential vectors of AHS. To establish if these midges fed on equids, DNA sequences were obtained from the gut contents of 52 female midges (35 freshly blood-fed, 13 gravid and four parous), representing 11 species collected across 11 sites. Culicoides leucostictus fed on all three equids. Culicoides bolitinos, Culicoides imicola and Culicoides magnus fed on both horses and donkeys. Culicoides onderstepoortensis fed on donkeys, and Culicoides similis and Culicoides pycnostictus fed on zebras. Bloodmeals from cows, pigs, warthogs, impalas and a domestic dog were also identified in various species, but none of the midges tested had fed on birds. These results contribute to knowledge of the vectorial capacity of several species of Culicoides with regard to AHS in the Eastern Cape and point to potential reservoir hosts, of which donkeys, zebras and domestic dogs have previously been found to harbour AHS. Blood-fed midges were also obtained throughout winter, indicating the potential for endemic AHS in the province.
- Full Text:
- Date Issued: 2019
- Authors: Riddin, M A , Venter, G J , Labuschagne, K , Villet, Martin H
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140692 , vital:37910 , DOI: 10.1111/mve.12381
- Description: An upsurge in African horse sickness (AHS) in the Eastern Cape, South Africa, from 2006 led to an epidemiological reassessment of the disease there. Light trapping surveys carried out near horses, donkeys and zebras in 2014–2016 collected 39 species of Culicoides midge (Diptera: Ceratopogonidae) that are potential vectors of AHS. To establish if these midges fed on equids, DNA sequences were obtained from the gut contents of 52 female midges (35 freshly blood-fed, 13 gravid and four parous), representing 11 species collected across 11 sites. Culicoides leucostictus fed on all three equids. Culicoides bolitinos, Culicoides imicola and Culicoides magnus fed on both horses and donkeys. Culicoides onderstepoortensis fed on donkeys, and Culicoides similis and Culicoides pycnostictus fed on zebras. Bloodmeals from cows, pigs, warthogs, impalas and a domestic dog were also identified in various species, but none of the midges tested had fed on birds. These results contribute to knowledge of the vectorial capacity of several species of Culicoides with regard to AHS in the Eastern Cape and point to potential reservoir hosts, of which donkeys, zebras and domestic dogs have previously been found to harbour AHS. Blood-fed midges were also obtained throughout winter, indicating the potential for endemic AHS in the province.
- Full Text:
- Date Issued: 2019
Hot-blooded singers: endothermy facilitates crepuscular signaling in African platypleurine cicadas (Hemiptera: Cicadidae: Platypleura spp.)
- Sanborn, Allen F, Villet, Martin H, Phillips, P K
- Authors: Sanborn, Allen F , Villet, Martin H , Phillips, P K
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6919 , http://hdl.handle.net/10962/d1011882
- Description: The cicada genus Platypleura has a wide distribution across Africa and southern Asia. We describe endothermic thermoregulation in four South African species that show crepuscular signaling behavior. This is the first evidence of thermoregulation in platypleurine cicadas. Field measurements of body temperature (Tb) show that these animals regulate Tb through endogenous heat production. Maximum Tb measured was 22.1°C above ambient temperature during calling activity at dusk. The mean Tb during dusk activity did not differ from the mean Tb during diurnal activity. A unique behavior for cicadas, a temperature-dependent telescoping pulsation of the abdomen, was observed in the laboratory during endogenous warm-up. This behavior is part of a unique method of heat generation in endothermic cicadas. Males generally call from trunks and branches within the canopy and appear to use endothermy even when the sun is available to elevate Tb. Endothermy may provide the cicadas with the advantage of decreasing predation and acoustic competition by permitting calling from perches that most complement their cryptic coloration patterns and that ectotherms cannot use due to thermal constraints. In addition, endothermy may permit calling activity during crepuscular hours when atmospheric conditions are optimal for acoustic communication and predation risks are minimal.
- Full Text:
- Date Issued: 2003
- Authors: Sanborn, Allen F , Villet, Martin H , Phillips, P K
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6919 , http://hdl.handle.net/10962/d1011882
- Description: The cicada genus Platypleura has a wide distribution across Africa and southern Asia. We describe endothermic thermoregulation in four South African species that show crepuscular signaling behavior. This is the first evidence of thermoregulation in platypleurine cicadas. Field measurements of body temperature (Tb) show that these animals regulate Tb through endogenous heat production. Maximum Tb measured was 22.1°C above ambient temperature during calling activity at dusk. The mean Tb during dusk activity did not differ from the mean Tb during diurnal activity. A unique behavior for cicadas, a temperature-dependent telescoping pulsation of the abdomen, was observed in the laboratory during endogenous warm-up. This behavior is part of a unique method of heat generation in endothermic cicadas. Males generally call from trunks and branches within the canopy and appear to use endothermy even when the sun is available to elevate Tb. Endothermy may provide the cicadas with the advantage of decreasing predation and acoustic competition by permitting calling from perches that most complement their cryptic coloration patterns and that ectotherms cannot use due to thermal constraints. In addition, endothermy may permit calling activity during crepuscular hours when atmospheric conditions are optimal for acoustic communication and predation risks are minimal.
- Full Text:
- Date Issued: 2003
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
The temporal occurrence of flesh flies (Diptera, Sarcophagidae) at carrion-baited traps in Grahamstown, South Africa
- Villet, Martin H, Clitheroe, Crystal, Williams, Kirstin A
- Authors: Villet, Martin H , Clitheroe, Crystal , Williams, Kirstin A
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59692 , vital:27639 , https://doi.org/10.3897/AfrInvertebr.58.9537
- Description: Eleven species of flesh fly were identified in a sample of 737 specimens captured during fortnightly trapping at three sites in Grahamstown, South Africa, over a year. Sarcophaga africa Wiedemann, 1824, S. inaequalis Austen, 1909, S. exuberans Pandelle, 1896 and S. tibialis Macquart, 1851 showed well-defined peaks between early October 2001 and late April 2002, and only S. africa was trapped at other times of year. These peaks occurred when average minimum and maximum ambient air temperatures were above 12°C and 22°C, respectively, and showed no obvious relationship to rainfall. There were indications of population cycles in all of these species. Sarcophaga hera Zumpt, 1972, S. arno Curran, 1934, S. inzi Curran, 1934, S. langi Curran, 1934, S. freyi Zumpt, 1953, S. nodosa Engel, 1925 and S. samia Curran, 1934 were too scarce to assess their patterns of occurrence rigorously. Insects attending a corpse are reputed to assist forensic entomologists in estimating the time of year when the body died. Some flesh flies provide more precise estimates than others, so several species should be used for cross-validation. Insect activity at a corpse depends on the weather, so that presence of a species indicates particular environmental conditions and not simply calendar dates (particularly if climate changes). Absence of a species is not necessarily evidence of specific conditions because species may not be present at all sites simultaneously, populations cycle even when their members are active, and low population densities may hamper detection of a species.
- Full Text:
- Date Issued: 2017
- Authors: Villet, Martin H , Clitheroe, Crystal , Williams, Kirstin A
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59692 , vital:27639 , https://doi.org/10.3897/AfrInvertebr.58.9537
- Description: Eleven species of flesh fly were identified in a sample of 737 specimens captured during fortnightly trapping at three sites in Grahamstown, South Africa, over a year. Sarcophaga africa Wiedemann, 1824, S. inaequalis Austen, 1909, S. exuberans Pandelle, 1896 and S. tibialis Macquart, 1851 showed well-defined peaks between early October 2001 and late April 2002, and only S. africa was trapped at other times of year. These peaks occurred when average minimum and maximum ambient air temperatures were above 12°C and 22°C, respectively, and showed no obvious relationship to rainfall. There were indications of population cycles in all of these species. Sarcophaga hera Zumpt, 1972, S. arno Curran, 1934, S. inzi Curran, 1934, S. langi Curran, 1934, S. freyi Zumpt, 1953, S. nodosa Engel, 1925 and S. samia Curran, 1934 were too scarce to assess their patterns of occurrence rigorously. Insects attending a corpse are reputed to assist forensic entomologists in estimating the time of year when the body died. Some flesh flies provide more precise estimates than others, so several species should be used for cross-validation. Insect activity at a corpse depends on the weather, so that presence of a species indicates particular environmental conditions and not simply calendar dates (particularly if climate changes). Absence of a species is not necessarily evidence of specific conditions because species may not be present at all sites simultaneously, populations cycle even when their members are active, and low population densities may hamper detection of a species.
- Full Text:
- Date Issued: 2017
A molecular phylogeny of the cicadas (Hemiptera: Cicadidae) with a review of tribe and subfamily classification:
- Marshall, David C, Moulds, Max, Hill, Kathy B R, Price, Benjamin W, Wade, Elizabeth J, Owen, Christopher L, Goemans, Geert, Marathe, Kiran, Sarkar, Vivek, Cooley, John R, Sanborn, Allen F, Kunte, Krushnamegh, Villet, Martin H, Simon, Chris
- Authors: Marshall, David C , Moulds, Max , Hill, Kathy B R , Price, Benjamin W , Wade, Elizabeth J , Owen, Christopher L , Goemans, Geert , Marathe, Kiran , Sarkar, Vivek , Cooley, John R , Sanborn, Allen F , Kunte, Krushnamegh , Villet, Martin H , Simon, Chris
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140601 , vital:37902 , DOI: 10.11646/zootaxa.4424.1.1
- Description: A molecular phylogeny and a review of family-group classification are presented for 137 species (ca. 125 genera) of the insect family Cicadidae, the true cicadas, plus two species of hairy cicadas (Tettigarctidae) and two outgroup species from Cercopidae. Five genes, two of them mitochondrial, comprise the 4992 base-pair molecular dataset. Maximum-likelihood and Bayesian phylogenetic results are shown, including analyses to address potential base composition bias. Tettigarcta is confirmed as the sister-clade of the Cicadidae and support is found for three subfamilies identified in an earlier morphological cladistic analysis. A set of paraphyletic deep-level clades formed by African genera are together named as Tettigomyiinae n. stat. Taxonomic reassignments of genera and tribes are made where morphological examination confirms incorrect placements suggested by the molecular tree, and 11 new tribes are defined (Arenopsaltriini n. tribe, Durangonini n. tribe, Katoini n. tribe, Lacetasini n. tribe, Macrotristriini n. tribe, Malagasiini n. tribe, Nelcyndanini n. tribe, Pagiphorini n. tribe, Pictilini n. tribe, Psaltodini n. tribe, and Selymbriini n. tribe). Tribe Tacuini n. syn. is synonymized with Cryptotympanini, and Tryellina n. syn. is synonymized with an expanded Tribe Lamotialnini. Tribe Hyantiini n. syn. is synonymized with Fidicinini. Tribe Sinosenini is transferred to Cicadinae from Cicadettinae, Cicadatrini is moved to Cicadettinae from Cicadinae, and Ydiellini and Tettigomyiini are transferred to Tettigomyiinae n. stat from Cicadettinae. While the subfamily Cicadinae, historically defined by the presence of timbal covers, is weakly supported in the molecular tree, high taxonomic rank is not supported for several earlier clades based on unique morphology associated with sound production.
- Full Text:
- Date Issued: 2018
- Authors: Marshall, David C , Moulds, Max , Hill, Kathy B R , Price, Benjamin W , Wade, Elizabeth J , Owen, Christopher L , Goemans, Geert , Marathe, Kiran , Sarkar, Vivek , Cooley, John R , Sanborn, Allen F , Kunte, Krushnamegh , Villet, Martin H , Simon, Chris
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140601 , vital:37902 , DOI: 10.11646/zootaxa.4424.1.1
- Description: A molecular phylogeny and a review of family-group classification are presented for 137 species (ca. 125 genera) of the insect family Cicadidae, the true cicadas, plus two species of hairy cicadas (Tettigarctidae) and two outgroup species from Cercopidae. Five genes, two of them mitochondrial, comprise the 4992 base-pair molecular dataset. Maximum-likelihood and Bayesian phylogenetic results are shown, including analyses to address potential base composition bias. Tettigarcta is confirmed as the sister-clade of the Cicadidae and support is found for three subfamilies identified in an earlier morphological cladistic analysis. A set of paraphyletic deep-level clades formed by African genera are together named as Tettigomyiinae n. stat. Taxonomic reassignments of genera and tribes are made where morphological examination confirms incorrect placements suggested by the molecular tree, and 11 new tribes are defined (Arenopsaltriini n. tribe, Durangonini n. tribe, Katoini n. tribe, Lacetasini n. tribe, Macrotristriini n. tribe, Malagasiini n. tribe, Nelcyndanini n. tribe, Pagiphorini n. tribe, Pictilini n. tribe, Psaltodini n. tribe, and Selymbriini n. tribe). Tribe Tacuini n. syn. is synonymized with Cryptotympanini, and Tryellina n. syn. is synonymized with an expanded Tribe Lamotialnini. Tribe Hyantiini n. syn. is synonymized with Fidicinini. Tribe Sinosenini is transferred to Cicadinae from Cicadettinae, Cicadatrini is moved to Cicadettinae from Cicadinae, and Ydiellini and Tettigomyiini are transferred to Tettigomyiinae n. stat from Cicadettinae. While the subfamily Cicadinae, historically defined by the presence of timbal covers, is weakly supported in the molecular tree, high taxonomic rank is not supported for several earlier clades based on unique morphology associated with sound production.
- Full Text:
- Date Issued: 2018
Effect of the killing method on post-mortem change in length of larvae of Thanatophilus micans (Fabricius, 1794) (Coleoptera: Silphidae) stored in 70% ethanol
- Midgley, John M, Villet, Martin H
- Authors: Midgley, John M , Villet, Martin H
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6857 , http://hdl.handle.net/10962/d1011140
- Description: It is recommended that insect larvae collected for forensic purposes should be killed using the same method as was used to create existing models for rate of development. Certain killing methods have been shown to be preferable because they cause less distortion of the specimens, but these are not always practicable in a particular case, and so a method of correcting for effect of killing method is required. Larvae of all instars of Thanatophilus micans (Fabricius 1794) (Coleoptera: Silphidae) were measured and then killed by immersion in ethanol, immersion in hot water or freezing. Samples were re-measured immediately after death, then stored in excess 70% ethanol and re-measured after 1 week and again after 4 weeks. The change in length was significantly different from zero in all samples (t = -9.07022, p < 0.001). An analysis of covariance showed that instar, killing method and storage time all had a significant effect on the change in length. The results showed that T. micans larvae have a great potential for change in length during storage but that the change is not predictable, as the magnitude and sign of the change are variable.
- Full Text:
- Date Issued: 2009
- Authors: Midgley, John M , Villet, Martin H
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6857 , http://hdl.handle.net/10962/d1011140
- Description: It is recommended that insect larvae collected for forensic purposes should be killed using the same method as was used to create existing models for rate of development. Certain killing methods have been shown to be preferable because they cause less distortion of the specimens, but these are not always practicable in a particular case, and so a method of correcting for effect of killing method is required. Larvae of all instars of Thanatophilus micans (Fabricius 1794) (Coleoptera: Silphidae) were measured and then killed by immersion in ethanol, immersion in hot water or freezing. Samples were re-measured immediately after death, then stored in excess 70% ethanol and re-measured after 1 week and again after 4 weeks. The change in length was significantly different from zero in all samples (t = -9.07022, p < 0.001). An analysis of covariance showed that instar, killing method and storage time all had a significant effect on the change in length. The results showed that T. micans larvae have a great potential for change in length during storage but that the change is not predictable, as the magnitude and sign of the change are variable.
- Full Text:
- Date Issued: 2009
Diversity of bacteria isolated from the flies Musca domestica (Muscidae) andChrysomya megacephala (Calliphoridae) with emphasis on vectored pathogens
- Brits, Devon, Brooks, Margot, Villet, Martin H
- Authors: Brits, Devon , Brooks, Margot , Villet, Martin H
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66904 , vital:28998 , ISSN 1021-3589 , https://doi.org/10.4001/003.024.0365
- Description: Publisher version , We evaluated the bacteria occurring externally on Musca domestica and Chrysomya megacephala, the two most common synanthropic flies which may be found at many refuse sites throughout the world. Bacteria cultured from 10 specimens of each species were isolated, Gram-stained and examined microscopically, and divided into morphologically distinct ‘pseudospecies', to avoid excessive duplication of genetic identification. About 350 bp of the 16S ribosomalRNAgene was amplified from genomicDNAextracted from each ‘pseudospecies', sequenced, and bacteria identified using BLASTn. Nineteen different types of colony were identified from M. domestica, with Pseudomonas sp. and Swine Manure Bacterium SP14 being most abundant. Chrysomya megacephala yielded 15 distinct pseudospecies with total colony counts approximating to 10 000 from 10 plates, where 80 % of colonies were non-pathogenic Bacillus pumilus. A total of 18 species were identified genetically: three shared by the fly species; four unique to C. megacephala, and 13 unique to M. domestica. Half of these 18 species were pathogenic, two or three others were food spoilers and the rest were environmental or commensal bacteria from soil or plant matter. This study added three new pathogenic strains of bacteria and one new environmental strain to the list of bacteria reported to be vectored by these flies.
- Full Text: false
- Date Issued: 2016
- Authors: Brits, Devon , Brooks, Margot , Villet, Martin H
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66904 , vital:28998 , ISSN 1021-3589 , https://doi.org/10.4001/003.024.0365
- Description: Publisher version , We evaluated the bacteria occurring externally on Musca domestica and Chrysomya megacephala, the two most common synanthropic flies which may be found at many refuse sites throughout the world. Bacteria cultured from 10 specimens of each species were isolated, Gram-stained and examined microscopically, and divided into morphologically distinct ‘pseudospecies', to avoid excessive duplication of genetic identification. About 350 bp of the 16S ribosomalRNAgene was amplified from genomicDNAextracted from each ‘pseudospecies', sequenced, and bacteria identified using BLASTn. Nineteen different types of colony were identified from M. domestica, with Pseudomonas sp. and Swine Manure Bacterium SP14 being most abundant. Chrysomya megacephala yielded 15 distinct pseudospecies with total colony counts approximating to 10 000 from 10 plates, where 80 % of colonies were non-pathogenic Bacillus pumilus. A total of 18 species were identified genetically: three shared by the fly species; four unique to C. megacephala, and 13 unique to M. domestica. Half of these 18 species were pathogenic, two or three others were food spoilers and the rest were environmental or commensal bacteria from soil or plant matter. This study added three new pathogenic strains of bacteria and one new environmental strain to the list of bacteria reported to be vectored by these flies.
- Full Text: false
- Date Issued: 2016