faunal succession and human decay april 13, 2009
TRANSCRIPT
Faunal Succession and Human Decay
Faunal Succession and Human Decay
April 13, 2009April 13, 2009
Faunistic StudiesFaunistic Studies
Based on ecological premise
Each sequential wave of organisms is unique
Usually requires entomological expertise
Can accurately estimate age of a corpse
Based on ecological premise
Each sequential wave of organisms is unique
Usually requires entomological expertise
Can accurately estimate age of a corpse
LimitationsLimitations
Faunistic studies can be used to estimate age of corpse
Accurate data
Accurate collection
Knowledge of perimortem activities
“This body was available for colonization on this date”
Faunistic studies can be used to estimate age of corpse
Accurate data
Accurate collection
Knowledge of perimortem activities
“This body was available for colonization on this date”
Ecological Categories of Carrion Community
Ecological Categories of Carrion Community
Necrophagous spp.
Sarcosaprophagous spp.
Most important
Feed on carrion itself
Necrophagous spp.
Sarcosaprophagous spp.
Most important
Feed on carrion itself
Ecological Categories of Carrion Community
Ecological Categories of Carrion Community
Predatory and Parasitic
On necrophagous spp.
Second most important
Beetles, flies, Assassin bugs, Wasps
Predatory and Parasitic
On necrophagous spp.
Second most important
Beetles, flies, Assassin bugs, Wasps
Ecological Categories of Carrion Community
Ecological Categories of Carrion Community
Omnivorous species
Both carrion and inhabitants
Adventive Species
Use carrion as extension of their environment
Omnivorous species
Both carrion and inhabitants
Adventive Species
Use carrion as extension of their environment
Ecological Categories of Carrion Community
Ecological Categories of Carrion Community
Accidental Species
Seek moisture
Resting place
Wide variety of insects
Plant-associating, others
Accidental Species
Seek moisture
Resting place
Wide variety of insects
Plant-associating, others
Roll of Necrophagous Invertebrates
Roll of Necrophagous Invertebrates
Important component of food web
Ecosystem defined
A biological community together with its physical environment (=habitat) which functions as a unit to capture and cycle energy and which does this more or less independently of other ecosystems
Important component of food web
Ecosystem defined
A biological community together with its physical environment (=habitat) which functions as a unit to capture and cycle energy and which does this more or less independently of other ecosystems
Roll of Necrophagous Invertebrates
Roll of Necrophagous Invertebrates
Environment Defined:
The total of circumstances surrounding an organism or group of organisms especially the combination of external or extrinsic physical conditions that affect and influence the growth, development and survival of organisms
Environment Defined:
The total of circumstances surrounding an organism or group of organisms especially the combination of external or extrinsic physical conditions that affect and influence the growth, development and survival of organisms
Basic Structure of a Food WebBasic Structure of a Food Web
Trophic: having to do with the process of nutrition
Trophic level: position of an animal in the food web
Producers
Primary Consumers
Secondary Consumers
Tertiary consumers
Quaternary consumers
Trophic: having to do with the process of nutrition
Trophic level: position of an animal in the food web
Producers
Primary Consumers
Secondary Consumers
Tertiary consumers
Quaternary consumers
Other Components of the Food Web
Other Components of the Food Web
Omnivores
Parasites
Transformers
Omnivores
Parasites
Transformers
Fresh StageFresh Stage
Initial decay
Algor mortis,livor mortis, rigor mortis, autolysis
Ectoparasites leave body
Eggs/early instars appear with onset of autolysis
Initial decay
Algor mortis,livor mortis, rigor mortis, autolysis
Ectoparasites leave body
Eggs/early instars appear with onset of autolysis
Eggs/early instars appear with onset of autolysis
Putrefaction StagePutrefaction Stage
Begins with the onset of bloat
1-3 days
Insect accelerate putrefaction
Liquefaction of muscles
larvae feed between muscles
Then on muscle fibers
Begins with the onset of bloat
1-3 days
Insect accelerate putrefaction
Liquefaction of muscles
larvae feed between muscles
Then on muscle fibers
Insect SuccessionInsect Succession
Necrophagous insects arrive on and in a corpse in somewhat predictable sequence
Ecological Succession
Seres: Series of blending waves of arthropods, each comprised of different organisms
Necrophagous insects arrive on and in a corpse in somewhat predictable sequence
Ecological Succession
Seres: Series of blending waves of arthropods, each comprised of different organisms
Importance of Succession
Importance of Succession
Extend PMI estimations
Describe or detect other incidents
Extend PMI estimations
Describe or detect other incidents
Arthropod SeresArthropod Seres
Number of seres variable
Megnin: 8 seres
Exposed corpse
Buried corpse--diversity markedly reduced
Number of seres variable
Megnin: 8 seres
Exposed corpse
Buried corpse--diversity markedly reduced
Sere State of Corpse Composition
#1 FreshBlow Flies, Filth Flies, Flesh
Flies
#2 Bloated Flesh Flies, Cynomya. sp
#3Putrid Advanced
DecaySkin beetles, Grease moths
#4Putrid Advanced
DecayCheese skippers, Fannia,
Sepsidae, Cleridae
#5Late Putrid
Advanced DecayDump flies, Phoridae,
Silphidae, Clown beetles
#6 Early Dry Stage Mites
#7Mid/late Dry
StageDermestidae, Tineidae
#8 Late Dry Stage Ptinidae, Tenebrionidae
Buried CorpseBuried Corpse
3 Seres:
Flies
Root eating Beetles
Rove beetles
3 Seres:
Flies
Root eating Beetles
Rove beetles
Other Successional Studies
Other Successional Studies
Animal carcasses
Number of seres varies
2-6
Attempt to define biological communities
Animal carcasses
Number of seres varies
2-6
Attempt to define biological communities
Summary of Findings to Date
Summary of Findings to Date
Broad general agreement of orders and families
General agreement of sequence
General agreement of dipteran sere
Broad general agreement of orders and families
General agreement of sequence
General agreement of dipteran sere
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