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Comparison of Single Diptera Species Decomposition vs. Diptera Community: Forensic Entomology Study

Investigating decomposition rates of Sarcophagidae vs. Calliphoridae on carcasses for forensic purposes. Explore larval growth and competition effects in a lab vs. wild setting.

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Comparison of Single Diptera Species Decomposition vs. Diptera Community: Forensic Entomology Study

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  1. Differential Decomposition of a Single Diptera Species (Sarcophagidae) versus a Community of Diptera Species (Calliphoridae) Emma Jones

  2. Introduction • Forensic entomology: • The process of studying the insects and arthropods on decomposing carcasses for legal and scientific purposes • Life cycle of flies on carcasses can be analyzed to determine how long decomposition has been occurring • Post-mortem interval (PMI): • The interval of time after death that helps entomologists determine how long a carcass has been decomposing by flies and other insects

  3. Sarcophagidae Sarcophagabullata • Commonly known as flesh flies • Larviparous: • The eggs develop internally and the females birth live larvae that is relatively large in size • Sarcophagabullatawere specifically used to represent the single species • Representative of a lab setting testing a single species of fly https://www.revolvy.com/page/Sarcophaga

  4. Calliphoridae • Commonly known as blow flies • Oviparous: • Females lay eggs which develop into larva outside of the female’s body • Make up the community, or Wildlife, sample • Representative of a natural setting with different species of flies Phormiaregina https://www.opsu.edu

  5. Review of Literature • Competition between Calliphoridae and Sarcophagidae has a direct impact on which species lays more on a carcass (Denno, 2011) • Maggot size is affected by the number of maggots present on the carcass (Rivers, 2010) • The rate at which larvae grow can be affected by the type of tissue they feed upon (Clark, 2005)

  6. Hypothesis H1 The single species, Sarcophagabullata, will have a faster rate of decomposition than the community of Calliphoridae (Wildlife). H0 There will be no statistically significant difference in decomposition rates between the single species, Sarcophagabullata, and the community of Calliphoridae (Wildlife) species.

  7. Methodology Water Cup Water Cup Fly Cage Fly Cage s. BullataPupae s. BullataPupae Sugar Cubes Sugar Cubes Liver/Heart Liver/Heart Wildlife Pupae Wildlife Pupae

  8. BloodFeeds Weighing the Blood Feed • One cup of mince, or ground beef • Placed in dish and weighed for initial weight prior to decomposition • Dish placed in fly cage to allow laying • Removed after 24 hours and transferred to a rearing dish Blood feed before decomposition Photo by Emma Jones Photo by Emma Jones

  9. Rearing Dishes Rearing Dish • An insulated environment for Wildlife eggs to hatch and the S. bullata’s larvae to mature • Blood feed placed in plastic container halfway filled with sand and covered with a piece of mesh • Sprayed with water three times twice a day • Kept outside of the fly cage for two weeks and then weighed for final weight after decomposition Blood feed after decomposition Photos by Emma Jones

  10. Results Wildlife. Weights and decomposition of community species (Calliphoridae) trials. • Average Percent Decomposed (Wildlife): 25.2% • Average Percent Decomposed (S. bullata): 30.2% • Difference: 5.0% S. bullata. Weights and decomposition of single species (Sarcophagidae) trials.

  11. Statistical Analysis • Differences in means of mass change by species (ANOVA F(1,8)=0.74, p=0.416, s.e.d. = standard error of difference)

  12. Discussion • The weight of the mince decreased significantly in all trials • The variety in species did not affect the flies ability to decompose the mince overall • Both the single species of flies and the community of species will decompose the mince • The number of varying species will not affect the overall decomposition in a statistically significant way

  13. Conclusion • The single species, Sarcophagabullata, did not have a faster rate of decomposition than the community of species, Calliphoridae • There was a difference between the average decompositions between the two samples • There was no statistical significance between the average decompositions of the two samples • There are no statistical differences between studying in a lab setting versus a natural setting

  14. Future Work • Change a few aspects of this research in attempt to find different results • Regulate the initial weight before decomposition creating another constant • Create new experiments with similar ideas • Specifically analyze how one species reacts in an isolated environment versus how the same species an environment with other species

  15. Acknowledgements • Mentor • Grad-student • Science Research Teacher • Chelsea Brown • My mom

  16. References Blow and Flesh Flies. (n.d.). Retrieved from https://hortnews.extension.iastate.edu/blow-and-flesh-flies Byrd, J. H., & Castner, J. L. (2010). Forensic entomology: The utility of arthropods in legal investigations. Boca Raton (Fla.): CRC Press. Catts, E. P., & Goff, M. L. (1992). Forensic Entomology in Criminal Investigations. Annual Review of Entomology,37(1), 253-272. doi:10.1146/annurev.en.37.010192.001345 Dadour, I., Cook, D., Fissioli, J., & Bailey, W. (2001). Forensic entomology: Application, education and research in Western Australia. Forensic Science International,120(1-2), 48-52. doi:10.1016/s0379-0738(01)00420-0 Denno, R. F., & Cothran, W. R. (1976). Competitive Interactions and Ecological Strategies of Sarcophagid and Calliphorid Flies Inhabiting Rabbit Carrion. Annals of the Entomological Society of America,69(1), 109-113. doi:10.1093/aesa/69.1.109 F, D., S, R., M, D., & P, B. (2016). The Use of Forensic Entomology in Legal Veterinary Medicine: A Case Study in the North of Italy. Journal of Forensic Science & Criminology,4(1). doi:10.15744/2348-9804.4.101 Greenberg, B. (1985). Forensic Entomology: Case Studies. Bulletin of the Entomological Society of America,31(4), 25-28. doi:10.1093/besa/31.4.25 Heaton, V., Moffatt, C., & Simmons, T. (2014). Quantifying the Temperature of Maggot Masses and its Relationship to Decomposition. Journal of Forensic Sciences,59(3), 676-682. doi:10.1111/1556-4029.12396 Order Diptera: The True Flies. (2011). The Royal Entomological Society Book of British Insects,177-225. doi:10.1002/9781444344981.ch19 O’Brien, R. C., Forbes, S. L., Meyer, J., & Dadour, I. R. (2007). A preliminary investigation into the scavenging activity on pig carcasses in Western Australia. Forensic Science, Medicine, and Pathology,3(3), 194-199. doi:10.1007/s12024-007-0016-3 Rognes, K. (2013). Blowflies (Diptera, Calliphoridae) of Fennoscandia and Denmark. Leiden: E.J. Brill. Szpila, K., Mądra, A., Jarmusz, M., & Matuszewski, S. (2015). Flesh flies (Diptera: Sarcophagidae) colonising large carcasses in Central Europe. Parasitology Research,114(6), 2341-2348. doi:10.1007/s00436-015-4431-1 Tomberlin, J. K. (2012). Assessment of Decomposition Studies Indicates Need for Standardized and Repeatable Research Methods in Forensic Entomology. Journal of Forensic Research,03(05). doi:10.4172/2157-7145.1000147 Voss, S. C., Forbes, S. L., & Dadour, I. R. (2007). Decomposition and insect succession on cadavers inside a vehicle environment. Forensic Science, Medicine, and Pathology,4(1), 22-32. doi:10.1007/s12024-007-0028-z

  17. Questions?

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