faunal succession and human decay april 13, 2009

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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Any Questions?Any Questions?