Carrion Fly and Disease Vector Activity Associated with a Decomposing Corpse

LTJG David England,MSC,USN LTJG David England,MSC,USN Medicolegal Entomology Medicolegal Entomology

Navy Entomology Center of ExcellenceNavy Entomology Center of ExcellenceNaval Air StationNaval Air StationJacksonville, FLJacksonville, FL

ObjectivesObjectives

1.1. Basic Methods For Estimating Basic Methods For Estimating Postmortem IntervalPostmortem Interval

2.2. Oregon Decomposition And Insect Oregon Decomposition And Insect Succession ModelSuccession Model

3.3. Current Forensic Entomology Current Forensic Entomology EndeavorsEndeavors

AccumulatedAccumulated

DegreeDegree

DayDay

HoursHours

Post MortemPost Mortem

IntervalInterval

(PMI)(PMI)

Estimation of PMIEstimation of PMI Insect succession Insect succession

patternspatterns Insect life cyclesInsect life cycles Influential Influential

variablesvariablesLife Cycle

Variables

Succession

PMIPMI

Variables that influence Variables that influence PMIPMI

TemperatureTemperature SeasonSeason SpeciesSpecies Death ScenarioDeath Scenario ToxicologyToxicology Parasitoids & PredatorsParasitoids & Predators

Insect SuccessionInsect Succession

Succession of insects generally follows a similar Succession of insects generally follows a similar pattern at the family level, but there are pattern at the family level, but there are variations at the genus and species levels with variations at the genus and species levels with respect to differing geographical locations respect to differing geographical locations

Forensic entomology ‘works’ because succession Forensic entomology ‘works’ because succession is a very predictable and consistent eventis a very predictable and consistent event

Site LocationSite Location

Soap Creek Soap Creek Ranch,Ranch,

18km NW of 18km NW of CorvallisCorvallis

Animal ModelAnimal Model

36 kg domestic pigs36 kg domestic pigs Euthanasia methodEuthanasia method ClothedClothed CagedCaged Human homicide Human homicide

scenarioscenario

Sampling Methods: Sampling Methods: Onsite & LaboratoryOnsite & Laboratory

Temperature readings: ambient, carcass and Temperature readings: ambient, carcass and maggot mass maggot mass

Insect SamplingInsect Sampling

Sticky, Pitfall, Hand Sample and NetSticky, Pitfall, Hand Sample and Net One Pig Weighed Daily (Change in Mass)One Pig Weighed Daily (Change in Mass) Growth ChambersGrowth Chambers

22°C and 12 hours controlled light22°C and 12 hours controlled light Identifications - OSU Insect CollectionIdentifications - OSU Insect Collection

Stages Of Stages Of Decomposition*Decomposition*

FreshFresh BloatedBloated Active DecayActive Decay Advanced DecayAdvanced Decay Dry RemainsDry Remains

**Catts and Haskell, 1990Catts and Haskell, 1990

Fresh StageFresh Stage

10 minutes PMI 10 minutes PMI Calliphoridae, Calliphoridae,

species species Lucilia Lucilia illustrisillustris (Meigen) (Meigen)

Egg clusters: Egg clusters: six hours PMIsix hours PMI

Reared and Reared and identifiedidentified

CalliphoridaeCalliphoridaeGreen bottle fly (Green bottle fly (Lucillia illustrisLucillia illustris))

Photo: http://bugguide.netPhoto: http://bugguide.net

Bloated Stage Bloated Stage

Eight hours - BloatingEight hours - Bloating 12 hours, bald-faced 12 hours, bald-faced

hornets hornets ((Dolichovespula Dolichovespula maculata) maculata) (Linnaeus)(Linnaeus)

33 hours PMI: the 33 hours PMI: the green bottle fly eggs green bottle fly eggs hatched hatched

48 hrs: Staphylinidae 48 hrs: Staphylinidae appearappear

Staphylinidae Staphylinidae

Brown and gold roveBrown and gold rove(Ontholestes cingulatus)(Ontholestes cingulatus)

Hairy roveHairy rove(Creopilus maxillosus(Creopilus maxillosus

Photo: http://bugguide.netPhoto: http://bugguide.net

Active Decay Stage Active Decay Stage

72 hour PMI72 hour PMI Red-tailed flesh flyRed-tailed flesh fly

((Sarcophaga Sarcophaga haemorrhoidalis)haemorrhoidalis)

Terrestrial isopodsTerrestrial isopods Adult green bottle fly Adult green bottle fly

decreasing decreasing Dermestidae, Dermestidae,

Silphidae, Histeridae Silphidae, Histeridae

Advanced Decay Stage Advanced Decay Stage

120 hours: carcass 120 hours: carcass began to desiccatebegan to desiccate

132 hours: third 132 hours: third instar/post feeding instar/post feeding maggotsmaggots

147 hours: maggot 147 hours: maggot mass exited carcassmass exited carcass

Large Large predator/scavenger predator/scavenger activity activity

Post Feeding ActivitiesPost Feeding Activities

Green bottle fly pupaeGreen bottle fly pupae

Dry Remains Stage Dry Remains Stage

288 hrs PMI288 hrs PMI DesiccatedDesiccated Beetle ActivityBeetle Activity No odorNo odor Seasonal rain mid- Seasonal rain mid-

OctoberOctober 25 days: scavengers 25 days: scavengers November: cages November: cages

removedremoved

November, 2005 November, 2005

Cage removedCage removed

April, 2006April, 20066 months 6 months after cage after cage removalremoval

6 months 6 months after cage after cage removalremoval

Decomposition SummaryDecomposition Summary

Green bottle fly within 10 minGreen bottle fly within 10 min Ovipositing/egg cluster 6 hrsOvipositing/egg cluster 6 hrs 33 hrs: first hatch33 hrs: first hatch 12 hrs: predators (hornet)12 hrs: predators (hornet) 72 hrs: predators (beetles)72 hrs: predators (beetles) 168 hrs: green bottle maggots left carcass168 hrs: green bottle maggots left carcass Jan. 1Jan. 1stst little evidence left; dead vegetation little evidence left; dead vegetation

Temperature SummaryTemperature Summary

Ambient temperatures (°C):Ambient temperatures (°C):

Mean 20.8; Min. 9.03; Max. 34.9Mean 20.8; Min. 9.03; Max. 34.9 Maggot mass temperature (°C):Maggot mass temperature (°C):

Mean 30.9; Max. 50.7 (128 hrs.PMI)Mean 30.9; Max. 50.7 (128 hrs.PMI) Mean RH: 50%Mean RH: 50% Precipitation: none until Oct.Precipitation: none until Oct.

Rate of DecompositionRate of Decomposition

Percentage of Mass Loss

0

20

40

60

80

100

1 2 3 4 5 6 7 8 9 10

Days

Mas

s %

mas

s

Decomposition RatesDecomposition Rates

Decomposition

0

1

2

3

4

5

0 5 10 15 20 25 30 35 40

Time

Mas

sLo

g of

% m

ass

Linearized Regression Analysis_______________________________________________________________Studies R² Slope (estimated) _______________________________________________________________

Grassberger: European Urban Habitat 1) May 0.907 -0.0786 2) Aug. 0.9677 -0.0586

Richards: Hawaiian Islands1) 1877 m 0.9338 -0.10752) 1169 m 0.8651 -0.1104

3) 646 m 0.8834 -0.1204

Anderson: SW British Columbia1) Carcass 1 0.9253 -0.0372

2) Carcass 2 0.9781 -0.0303

England: Corvallis, Oregon 1) Carcass 1 0.9517 -0.2378

SummarySummary

Regional ModelRegional Model Standardized AnalysisStandardized Analysis

* * All slope values produced consistent results*Exponential decomposition rate that can be evaluated with linearization

Utilized In Further Research (geography, Utilized In Further Research (geography, seasons, scenarios, etc.)seasons, scenarios, etc.)

Current Forensic Current Forensic Entomology EndeavorsEntomology Endeavors

Provide Entomological Training For Provide Entomological Training For Naval Criminal Investigation ServiceNaval Criminal Investigation Service

Georgia Research With Naval Criminal Georgia Research With Naval Criminal Investigation ServiceInvestigation Service

Iraq Fly SamplesIraq Fly Samples

AcknowledgementsAcknowledgements

Dr. Phil RossignolDr. Phil Rossignol

Dr. Anne RossignolDr. Anne Rossignol

Dr. Brian CroftDr. Brian Croft

Dr. Paul JespersenDr. Paul Jespersen

CDR SzumlasCDR Szumlas

Joyce TakyasuJoyce Takyasu

Clint SextonClint Sexton

Questions and

Discussion