Estimating the age of immature Chrysomya albiceps (Diptera: Calliphoridae), correcting for temperature and geographical latitude
- Richards, Cameron S, Paterson, Iain D, Villet, Martin H
- Authors: Richards, Cameron S , Paterson, Iain D , Villet, Martin H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442129 , vital:73961 , https://doi.org/10.1007/s00414-007-0201-7
- Description: Developmental curves for Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) were established at 13 different constant temperatures using developmental landmarks and length as measures of age. The thermal summation constants (K) and developmental zeros (D 0) were calculated for five developmental landmarks using the method described by Ikemoto and Takai (Environ Entomol 29:671–682, 2000). Comparison with the K and D 0 values of our findings to those of three previously published studies of C. albiceps suggests that K is directly proportional to geographic latitude, and D 0 is inversely proportional to both K and geographic latitude. Body size and developmental landmarks have a complex relationship because of trade-offs between mortality risk and female fecundity (as measured by body size) at non-optimal temperatures. This relationship can be summarized using superimposed isomorphen and isomegalen diagrams, which can then be used to make forensic estimates of postmortem intervals from larval body lengths. Finally, we recommend that future studies providing data for precise forensic estimates of postmortem intervals should use a relative temporal precision of about 10% of the total duration being measured. For many blowflies, this translates into a sampling interval of approximately every 2 h before hatching, 3 h before first ecdysis and 6 h before second ecdysis.
- Full Text:
- Date Issued: 2008
- Authors: Richards, Cameron S , Paterson, Iain D , Villet, Martin H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442129 , vital:73961 , https://doi.org/10.1007/s00414-007-0201-7
- Description: Developmental curves for Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) were established at 13 different constant temperatures using developmental landmarks and length as measures of age. The thermal summation constants (K) and developmental zeros (D 0) were calculated for five developmental landmarks using the method described by Ikemoto and Takai (Environ Entomol 29:671–682, 2000). Comparison with the K and D 0 values of our findings to those of three previously published studies of C. albiceps suggests that K is directly proportional to geographic latitude, and D 0 is inversely proportional to both K and geographic latitude. Body size and developmental landmarks have a complex relationship because of trade-offs between mortality risk and female fecundity (as measured by body size) at non-optimal temperatures. This relationship can be summarized using superimposed isomorphen and isomegalen diagrams, which can then be used to make forensic estimates of postmortem intervals from larval body lengths. Finally, we recommend that future studies providing data for precise forensic estimates of postmortem intervals should use a relative temporal precision of about 10% of the total duration being measured. For many blowflies, this translates into a sampling interval of approximately every 2 h before hatching, 3 h before first ecdysis and 6 h before second ecdysis.
- Full Text:
- Date Issued: 2008
Factors affecting accuracy and precision of thermal summation models of insect development used to estimate post-mortem intervals
- Richards, Cameron S, Villet, Martin H
- Authors: Richards, Cameron S , Villet, Martin H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442142 , vital:73962 , https://doi.org/10.1007/s00414-008-0243-5
- Description: This paper investigates the effects that different summary statistics (minimum, median, mean, or maximum), temporal sampling resolutions (duration between sampling events), and sample sizes (number of individuals sampled per sampling event) had on the accuracy and precision of the regression coefficients of a typical thermal summation model used to calculate minimum post-mortem interval (PMI). No significant differences were found in the values of the developmental constants calculated from different summary statistics of the duration of development. Sample size was found to affect the precision of measurement of the duration of development but had little overall influence on thermal summation constant (K) and developmental threshold (D 0) calculations (and therefore, subsequent PMI estimates), but temporal sampling resolution had a direct influence on the accuracy of K and D 0 calculations. These data suggest that when numbers of experimental maggots are limited, it is more important to sample more frequently using smaller sample sizes than to sample less frequently with large sample sizes. Furthermore, we suggest that the median is the most representative summary measure of the duration of development and should be used preferentially.
- Full Text:
- Date Issued: 2008
- Authors: Richards, Cameron S , Villet, Martin H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442142 , vital:73962 , https://doi.org/10.1007/s00414-008-0243-5
- Description: This paper investigates the effects that different summary statistics (minimum, median, mean, or maximum), temporal sampling resolutions (duration between sampling events), and sample sizes (number of individuals sampled per sampling event) had on the accuracy and precision of the regression coefficients of a typical thermal summation model used to calculate minimum post-mortem interval (PMI). No significant differences were found in the values of the developmental constants calculated from different summary statistics of the duration of development. Sample size was found to affect the precision of measurement of the duration of development but had little overall influence on thermal summation constant (K) and developmental threshold (D 0) calculations (and therefore, subsequent PMI estimates), but temporal sampling resolution had a direct influence on the accuracy of K and D 0 calculations. These data suggest that when numbers of experimental maggots are limited, it is more important to sample more frequently using smaller sample sizes than to sample less frequently with large sample sizes. Furthermore, we suggest that the median is the most representative summary measure of the duration of development and should be used preferentially.
- Full Text:
- Date Issued: 2008
Forensic Entomology: An Introduction, D.E. Gennard book: review
- Villet, Martin H, Richards, Cameron S
- Authors: Villet, Martin H , Richards, Cameron S
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451690 , vital:75070 , https://hdl.handle.net/10520/EJC32766
- Description: Since the publication of Smith's (1986) "A manual of forensic entomology", there have been a series of useful texts in forensic entomology, some written as authoritative resources (Byrd and Castner 2001; Greenberg and Kunish 2002; Wyss and Cherix 2006) and others as training manuals (Catts and Haskell 1990). Dorothy Gennard's contribution is a bit of both, being the first text written primarily as a broad introduction to medico-criminal forensic entomology for specialised undergraduate classes.
- Full Text:
- Date Issued: 2008
- Authors: Villet, Martin H , Richards, Cameron S
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451690 , vital:75070 , https://hdl.handle.net/10520/EJC32766
- Description: Since the publication of Smith's (1986) "A manual of forensic entomology", there have been a series of useful texts in forensic entomology, some written as authoritative resources (Byrd and Castner 2001; Greenberg and Kunish 2002; Wyss and Cherix 2006) and others as training manuals (Catts and Haskell 1990). Dorothy Gennard's contribution is a bit of both, being the first text written primarily as a broad introduction to medico-criminal forensic entomology for specialised undergraduate classes.
- Full Text:
- Date Issued: 2008
- «
- ‹
- 1
- ›
- »