Forensic Entomology

Forensic Entomology
Bugs in crime

What is that?

Forensic Entomology

Forensic entomology is the study of the application of insects and other arthropods in criminal investigation.[1] Insects or arthropods are found in a decomposing vertebrate corpse or carrion.

Why use bugs?

Time keepers

Insects or arthropods are found in a decomposing vertebrate corpse or carrion. These insect colonizers can be used to estimate the time of death i.e., time interval between death and corpse discovery, also called postmortem index (PMI), movement of the corpse, manner and cause of death and association of suspects at the death scene

Multiple Choice

How are entomology and forensic entomology different?

• Entomology studies insects while forensic entomology studies insects in application to civil and criminal legal cases.

• Entomology studies insects in application to civil and criminal legal cases while forensic entomology studies insects.

• Trick! They are both the same.

• This is not the answer.

Multiple Choice

application of entomology to civil & criminal legal cases

• forensic entomology

• forensic anthropology

• forensic odontology

• forensic epidemiology

Which bugs exactly?

Flies

The predominant species in this order are Calliphoridae (blow flies), Sacrophagidae (flesh flies) and Muscidae (house flies). Calliphoridae (blow flies), Sacrophagidae (flesh flies) may arrive within minutes following death. Muscidae (house flies) delay colonization until the body reaches bloat stages of decomposition.

Blow flies: any member in a family of insects in the fly order, Diptera, that are metallic blue, green, or black in colour and are noisy in flight.

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Calliphoridae

​Blow fly life cycle typically takes 3 – 4 weeks depending on the species. The life cycle is broken up into three distinct stages, the egg, the larvae and the adult

Flesh flies:

​Have a checked pattern on top of their abdomen alongside three black stripes running along the top of their thorax and red eyes.

Sacrophagidae

​complete metamorphosis through four life stages: egg, larva, pupa, and adult. The complete life cycle takes approximately 23 days under laboratory conditions from 1st larvae to adult.

House flies:

​Adults are gray to black, with four dark, longitudinal lines on the thorax, slightly hairy bodies, and a single pair of membranous wings. They have red eyes, set farther apart in the slightly larger female.

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Muscidae

​As it turns out, an adult female house fly typically lives for about 25 days (males live for about 15 days).

Multiple Choice

breakdown of once living matter by living organisms

• instar

• larva

• decomposition

• insect succession

Multiple Choice

body development in 4 stages: egg, larva, pupa, & adult

• complete metamorphosis

• grub

• oviposition

• spiracles

Multiple Choice

Which of these shows the correct order for a fly's life cycle?

• A --> B --> C --> D

• B --> C --> D--> A

• B --> D --> A --> C

• D --> B --> C -->A

• Fresh stage (Days 1-2): which begins at the moment of death and ends when the bloating of the carcass is observed.

• Bloated stage (Days 2-7): Putrefaction begins at this stage. Gases produced by the metabolic activities of anaerobic bacteria cause an inflation of the abdomen and the carcass forming a balloon-like appearance during the later part.

• (active) Decay stage (Days 5-13): Abdominal wall is penetrated, resulting in the deflation of the carcass and ending the bloated stage, the internal temperature rises to 14 degrees above the ambient temperature followed by a drop signifying the end of the decay stage.

​Five stages of decomposition

Five stages of decomposition

• (advanced) Post-decay stage (Days 10-23): The post-decay stage begins when most of the Diptera larvae leave the carcass, leaving behind bones, cartilage, hair, small portions of tissue, and a large amount of wet, viscous material known as byproducts of decay (BOD). The BOD is the major site of arthropod activity during this stage.

• Remains stage/dry or skeletal (Days 18-90+): This stage is characterized by bones with little cartilage remaining and the BOD has dried up.

Multiple Choice

stage 3 of decomposition

• active decay

• dry or skeletal

• advanced decay

• fresh stage

• bloating

Multiple Choice

stage 1 of decomposition

• fresh stage

• skeletal or dry

• advanced decay

• bloating

• active decay

Multiple Choice

stage 2 of decomposition

• bloating

• advanced decay

• active decay

• fresh stage

• dry or skeletal

Multiple Choice

stage 4 of decomposition

• advanced decay

• bloating

• fresh

• dry or skeletal

• active decay

Multiple Choice

stage 5 of decomposition

• dry or skeletal

• fresh

• advanced decay

• active decay

• bloating