Entomology

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PMI estimation

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Entomology

  1. 1. 1Insect succession and carrion decomposition in selected forests of Central Europe. Part 2: Composition and residency patterns of carrion faunaSzymon Matuszewski,Daria Bajerlein,Szymon Konwerski,Krzysztof Szpila Presenter – Divyanshu Singh 1
  2. 2. Introduction• PMI ??• After death body undergoes many changes• Forensic entomology - insect activity on the corpse• Analysis of composition of carrion fauna and selected features of residency in carrion in adults and larvae of particular taxa.• Implications for  Succession-based post-mortem interval (PMI) estimation  Determination of the carcass movement  Determination of the season of death 2
  3. 3. The Approach•Determine the forensic usefulness of carrion insects by  recognition of reoccurring taxa  quantify feature of residency  relationship between a given taxon presence and a particular state of the carcass• Factors considered: • Seasons - spring, summer and autumn • Forest type - pine-oak forest, hornbeam-oak forest and alder forest 3
  4. 4. Data Analysis, Results and Discussion1. The composition of carrion fauna2. The residency patterns of carrion fauna3. The relationship between appearance time of carrion fauna and onsets of decomposition processes 4
  5. 5. The composition of carrion fauna• Two-way analysis of variance (ANOVA) Evaluate the significance of season and forest effect on the number of minimally abundant taxa.•The composition of adult and larva of Diptera andColeopteraNumber of taxa minimally abundant in adult stageNumber of taxa minimally abundant in larval stage 5
  6. 6. Observation Seasonal differences seen Differences in pattern results from • the seasonality of carrion taxa • seasonal differences in decomposition Not much differences seen in different forest types 6
  7. 7. The residency patterns of carrion fauna• Comparison of taxa• Determination of  Length of the presence period  Number of breaks in the presence period  Length of the longest unbroken period• To calculate relative length of the presence period (RLPP)RLPP = LPP * 100% (LPP-length of presence period LSI LSI-length of sampling interval.) 7
  8. 8. Observation  Length of the presence period in Diptera and Coleoptera • Closer the relation between a taxon and carrion, shorter is its presence period. • Presence period of carrion-breeders was seen to be 46% and carrion feeders 66%.  Breaks in the presence period in Diptera and Coleoptera • Residency was broken in case of adult carrion taxa and unbroken in case of larval carrion taxa .C – a reoccurring taxon with breaks clumped, b – a break in the presence period, lup – the longestunbroken period, pp – the presence period. 8
  9. 9. The relationship between appearance time ofcarrion fauna and onsets of decompositionprocesses  Correlational analysis To evaluate the relationship between the appearance time of a taxon and different decompositional processes  The Pearson product–moment correlation coefficient used • Outliers in scatterplot omitted • Results of significant taxa presented 9
  10. 10. Observation Key Variable affecting decomposition - Ambient temperature Ambient temperature closely related to • Onset of bloating • Appearance time of taxon 10
  11. 11. Implications for forensic entomology Estimation of PMI • Presence or absence of taxa on the carcass Determination of the carcass movement • Differences between forest and open habitats suggest the composition of insect fauna Determination of the season of death • 2 season or 1 season taxa • More experimentation needed 11
  12. 12. Take Home Message For the composition of carrion fauna, large differences between seasons, but no important differences between forest types. Residency of adults was broken, residency of larvae was unbroken. In adults, two distinct residency patterns observed; • with breaks clumped in the final part of the presence period • with breaks evenly distributed inside the presence period Almost in all taxa, the time of appearance showed the closest, significant, positive and strong relationship to the onset of bloating. 12
  13. 13. 13 References1. http://entomology.wsu.edu/courses/coursefiles/ENTOM101/ENT101%20Fall200 6/ent%20101%20carrion%202006.pdf3. S. Matuszewski, D. Bajerlein, S. Konwerski, K. Szpila, Insect succession and carrion decomposition in selected forests of Central Europe. Part 1: Pattern and rate of decomposition, Forensic Sci. Int. (2009), doi:10.1016/j.forsciint.2009.10.016.5. J.D. Wells, L.R. LaMotte, Estimating the postmortem interval, in: J.H. Byrd, J.L. Castner (Eds.), Forensic Entomology. The Utility of Arthropods in Legal Investigations,CRC Press, Boca Raton, 2001, pp. 263–285.6. www.google.co.in8. www.wikipedia.org Castner (Eds.), Forensic Entomology. The Utility of Arthropods in Legal Investigations,CRC Press, Boca Raton, 2001, pp. 263–285.11. http://www.benecke.com/pdf-files/elderlyneglect.pdf13. http://en.wikipedia.org/wiki/Post-mortem_interval 13
  14. 14. Thank you for your attention! 14

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