Powerpoint presentation of Practical Forensic Research Project.

1. Examination of Decomposition and Insect Activity Variations of Sunlit and Shaded Carrion during Winter Forensic Research Project by Esther Breen Supervised by: Catherine Fitzgerald Bryan Lessard Jodie Ward

5. Blowfly Lifecycle 7 Myskowiak J, & Doums C, 2002 ‘ Effects of refrigeration on the biometry and development of Protophormia terranovae (Robineau-Desvoidy) (Diptera: Calliphoridae) and its consequences in estimating post-mortem interval in forensic investigations’, Forensic Science International , Vol. 125, p. 254-261. Figure 1: The blowfly lifecycle 7 .

9. Figure 2: Death scene data form

11. Figure 3: Mean daily temperature for sunlit and shaded carrion. (a) represents mean daily ambient and body temperature of the sunlit carrion and (b) represents the mean daily ambient and body temperature shaded carrion. (a) showed similar daily mean temperatures in the sunlit carrion of P05, P07 and P09 with no strong differences. In contrast (b) had similar temperature in the shaded carrion in P06 and P08 with a spike of warmer daily temperature in P10. In comparison there are no strong differences in daily mean ambient and body temperature between the sunlit and shaded. b) a) Temperature

13. Table 1: Sunlit and shaded comparison of P05 and P06 88 46 3 Shaded (Pig 6) Sunlit (Pig 5) Day

14. Table 2: Sunlit and shaded comparison of P07 and P08. 88 46 3 Shaded (Pig 8) Sunlit (Pig 7) Day

15. Table 3: Sunlit and shaded comparison of P09 and P10. 88 46 3 Shaded (Pig 10) Sunlit (Pig 9) Day

17. Figure 4: Comparison of insect populations during Fresh stage of decomposition between sunlit and shaded carrion.

18. Figure 5: Comparison of insect populations during Bloat stage of decomposition between sunlit and shaded carrion.

19. Figure 6: Comparison of insect populations during Bloat stage of decomposition between sunlit and shaded carrion.

20. Table: Insect species found on carrion at each stage of decomposition.

21. Figure 7: Insect species observed on the carrion. Diptera: a) Calliphora stygia b) Muscidae sp. c) Sarcophaga aurifrons d) Piophila casei e) Chironomidae sp. Coleoptera: f) Scarabidae sp. g) Necrobia rufipes h) Cleridae sp. i) Curculionoidea sp. j) Paederus sp . Hymenoptera: k) Diapriidae sp. l) Rhytidoponera metallica m) Monomorium minimum . Acari: n) Tetranychidae sp. Gastrura: o) Gastrura sp . Photographs by Esther Breen. a) b) c) d) e) f) g) h) i) j) k) l) m) n) o) Insect Species Present

24. Table 4:Calculation of the ADD for Calliphora stygia rate of development.

25. Discussion Temperature variations between sunlit and shaded carrion were not significantly different throughout the experiment. The temperature and humidity recorded by the data loggers from each carrion observed may have resulted in more significant figures if some had not failed. The data from the ThermochronTM logger, which was placed inside the carrion, and the underneath HydrochronTM logger would have resulted in maggot mass temperature variations which could have been compared. The rate of decomposition showed no significant differences between the sunlit and shaded carrion but decomposition was increased when warmer temperatures enhanced insect activity. This was obvious in P05 which had an abundance of insects present during most of the study. P06 showed substantial decomposition of the rear area, which received the most ambient warmth and sunlight through the shade cloth in the afternoons, whilst the upper portion of the body was in shade from a nearby tree. However the habitat also did appear to have an effect on the rate of decomposition. The soft tissue mummified in sunlit carrion, which would have made the skin tougher and harder for the insects and maggots to digest, slowing the rate of decomposition. Whereas, the soft tissue in the shaded carrion; developed adipocere around them which appeared to drown a number of insects trying to reach the carcass.

26. Shean et al. 12 determined that the ambient air temperature was the major factor that influenced variations in carrion decomposition between sunlit and shaded locations. This is supported by Joy et al. 13 who observed a greater rate of decomposition in higher ambient temperatures sunlit and shaded carrion decomposition. The sunlit carrion decomposed more rapidly compared to the shaded carrion, even when the ambient temperature was not significantly different. This may be related to variations in environmental conditions experienced by the carrion. The insect activity of the sunlit and shaded carrion presented very similar species with the sunlit carrion increasing in population for insects during all stages of decomposition, especially the Diptera species. The abundance of Diptera in sunlit locations was likely due to the warmer temperature increasing the activity of maggots and blowflies. Some species also showed a preference for the sunlit locations with no occurrence of these species on the shaded carrion. Hymenoptera were more abundant in the shaded location compared to the sunlit during the Bloat stage. But this may have been the result of increased larvae and eggs from the blowflies in the moist, shaded environment which would have provided more food and reproductive sources for certain species of parasitic wasp and ants. 12 Shean BS, Messinger L, & Papworth M, 1993 ‘Observtions of different decomposition on sun exposed v. shaded pig carrion in coastal washington state’, Journal of Forensic Science , Vol. 38, p. 938-949 13 Joy JE, Liette NL, & Harrah HL, 2006 ‘Carrion fly (Diptera: Calliphoridae) larval colonisation of sunlit and shaded pig carcasses in west virginia, USA’ Forensic Science International, Vol. 149, no.2-3, p. 57-65

30. Conclusion The current experiment demonstrated that the winter in the Canberra region reduced the rate of decomposition, which extended the stages of Fresh, Bloat and Decay over 90 days. The sunlit and shaded pig carrion showed no significant difference in rate of decomposition, however changes in soft tissue were observed showing mummification in the dry, sunlit habitats and the formation of adipocere in the moist, shaded habitats. Temperature variations between the two habitats showed no significant difference in ambient temperature or body temperature, but the control samples did demonstrated that the rate of decomposition was linked to the insect activity. When examining insect activity in sunlit and shaded locations, a significant difference between insect populations was observed. Diptera abundance was almost doubled at sunlit carrion sites throughout the stages of decomposition in comparison to shaded carrion, with slight variations in Hymenoptera and Coleoptera numbers. However, the Hymenoptera population was more abundant at shaded sites during Bloat. There also were observable preferences between some species for sunlit or shaded environments. when examining the development rate and ADD of blowflies at this time of year, errors in PMI due to cold weather which may delay the oviposition of eggs and reduce the growth rate of larvae can cause inaccuracies in PMI estimates. Therefore, temperature conditions which are below a species minimum temperature threshold and which stunt larvae development should be taken into consideration when estimating the PMI.

31. Future Directions and Research The current study had some limitations which could be improved in future sunlit and shaded carrion examination. Further consideration of location differences of sunlit and shaded carrion, and differences of seasonal and yearly data would contribute significantly to the research. Additional data from maggot mass temperatures, laboratory reared maggots and effective data loggers would also be beneficial. A comprehensive study of variations in Calliphora stygia larval weight, length, development rate and minimum temperature threshold for cold temperature conditions, which are collected from the Canberra region, could provide more information for estimating PMI during winter. Also the statistical error in delayed oviposition and the accuracy of PMI estimations could be examined to determine a standard error rate.