Carrion Fly and Disease Vector Activity Associated with a Decomposing Corpse LTJG David England,MSC,USN Medicolegal Entomology Navy Entomology Center of Excellence Naval Air Station Jacksonville, FL

Objectives 1.Basic Methods For Estimating Postmortem Interval 2.Oregon Decomposition And Insect Succession Model 3.Current Forensic Entomology Endeavors

AccumulatedDegreeDayHours Post Mortem Interval(PMI)

Estimation of PMI  Insect succession patterns  Insect life cycles  Influential variables Life Cycle Variables SuccessionPMI

Variables that influence PMI  Temperature  Season  Species  Death Scenario  Toxicology  Parasitoids & Predators

Insect Succession Succession of insects generally follows a similar pattern at the family level, but there are variations at the genus and species levels with respect to differing geographical locations Forensic entomology ‘works’ because succession is a very predictable and consistent event

Site Location Soap Creek Ranch, 18km NW of Corvallis

Animal Model  36 kg domestic pigs  Euthanasia method  Clothed  Caged  Human homicide scenario

Sampling Methods: Onsite & Laboratory  Temperature readings: ambient, carcass and maggot mass  Insect Sampling Sticky, Pitfall, Hand Sample and Net  One Pig Weighed Daily (Change in Mass)  Growth Chambers 22°C and 12 hours controlled light 22°C and 12 hours controlled light  Identifications - OSU Insect Collection

Stages Of Decomposition*  Fresh  Bloated  Active Decay  Advanced Decay  Dry Remains * Catts and Haskell, 1990

Fresh Stage  10 minutes PMI  Calliphoridae, species Lucilia illustris (Meigen)  Egg clusters: six hours PMI  Reared and identified

Calliphoridae Green bottle fly (Lucillia illustris) Photo:

Bloated Stage  Eight hours - Bloating  12 hours, bald-faced hornets (Dolichovespula maculata) (Linnaeus)  33 hours PMI: the green bottle fly eggs hatched  48 hrs: Staphylinidae appear

Staphylinidae Brown and gold rove (Ontholestes cingulatus) Hairy rove (Creopilus maxillosus Photo:

Active Decay Stage  72 hour PMI  Red-tailed flesh fly (Sarcophaga haemorrhoidalis)  Terrestrial isopods  Adult green bottle fly decreasing  Dermestidae, Silphidae, Histeridae

Advanced Decay Stage  120 hours: carcass began to desiccate  132 hours: third instar/post feeding maggots  147 hours: maggot mass exited carcass  Large predator/scavenger activity

Post Feeding Activities

Green bottle fly pupae

Dry Remains Stage  288 hrs PMI  Desiccated  Beetle Activity  No odor  Seasonal rain mid- October  25 days: scavengers  November: cages removed

November, 2005 Cage removed Cage removed April, months after cage removal

Decomposition Summary  Green bottle fly within 10 min  Ovipositing/egg cluster 6 hrs  33 hrs: first hatch  12 hrs: predators (hornet)  72 hrs: predators (beetles)  168 hrs: green bottle maggots left carcass  Jan. 1 st little evidence left; dead vegetation

Temperature Summary  Ambient temperatures (°C): Mean 20.8; Min. 9.03; Max  Maggot mass temperature (°C): Mean 30.9; Max (128 hrs.PMI)  Mean RH: 50%  Precipitation: none until Oct.

Rate of Decomposition % mass

Decomposition Rates Log of % mass

Linearized Regression Analysis _______________________________________________________________ Studies R² Slope (estimated) _______________________________________________________________ Grassberger: European Urban Habitat 1) May ) Aug Richards: Hawaiian Islands 1) 1877 m ) 1169 m ) 646 m Anderson: SW British Columbia 1) Carcass ) Carcass England: Corvallis, Oregon 1) Carcass

Summary  Regional Model  Standardized Analysis * * All slope values produced consistent results *Exponential decomposition rate that can be evaluated with linearization  Utilized In Further Research (geography, seasons, scenarios, etc.)

Current Forensic Entomology Endeavors  Provide Entomological Training For Naval Criminal Investigation Service  Georgia Research With Naval Criminal Investigation Service  Iraq Fly Samples

Acknowledgements Dr. Phil Rossignol Dr. Anne Rossignol Dr. Brian Croft Dr. Paul Jespersen CDR Szumlas Joyce Takyasu Clint Sexton

Questions and Discussion