Bugs Don’t Lie July 9, 1997 Champaign County, Ohio Stepfather, Kevin Neal, claims stepchildren are missing from their back yard Bodies discovered on September 6th were in the late stages of decomposition Autopsies revealed Maggot infestation Absence of blowflies and screwworms Presence of cheese skipper fly in its 3rd instar stage How were these insects evaluated? Forensic Science II: Forensic Entomology, Chapter 12 © 2012 Cengage Learning. All Rights Reserved

After Death As the body decays, odors attract insects to the dead body. The flies are the first to arrive. Blowflies and flesh flies are flesh feeders and will be the first in line. If no trauma is present on the body, female blowflies will lay eggs in exposed body openings.

Estimating Time of Death Factors affecting insect development Temperature Wind Time of day Season Exposure to elements Estimation of time of death obtained by raising insects from scene in same conditions at lab. Process is known as Accumulated Degree Hours (ADH) scienceinschool.org

Time of Death - Insects Blowfly eggs can be found in the moist, warm areas of a corpse within 8 hours after death. They will have progressed to the 1st of their 3 larva stages within 20 hours. By the 4th or 5th day they will have progressed to the 3rd of their 3 larva stages.

Time of Death - Insects By the 8th or 12th day the larvae will migrate away from the corpse to a dry place. Becoming pupa and immobile within 18-24 days, they will change from white to dark brown. By the 21st-24th day the pupa cases will split open and adult blowflies will emerge.

Forensic Science: Fundamentals & Investigations, Chapter 11 Image: http://www.nlm.nih.gov/visibleproofs

Phormia regina Spiracles are incomplete Third-instar larvae

Phaenicia sp Spiracles are complete Third-instar larvae

Postmortem Interval - PMI Postmortem Interval- the time elapsed since a person died When longer than 72 hours after death, entomology becomes important Within 48 hours the female blowfly lays eggs in moist areas of the body Forensic Science II: Forensic Entomology, Chapter 12 © 2012 Cengage Learning. All Rights Reserved

Postmortem Interval - PMI Forensic Entomology is used to determine time since death (the time between death and corpse discovery) This is called postmortem interval or PMI. scienceinschool.org

Postmortem Interval - PMI Entomological evidence collection Identify the species Document larvae length Determine the instar Determine PMI documentingreality.com

Collecting & Preserving Evidence Observe and record all pertinent factors Weather patterns (rainfall, wind, humidity, temperature, and exposure to light) during the PMI Avoid disturbing insects within several feet of the body Measure distance from body to insects Collect samples of all insect stages on, near, and under the body Forensic Science II: Forensic Entomology, Chapter 12 © 2012 Cengage Learning. All Rights Reserved

Collecting & Preserving Evidence Capture live flies with nets Pin flies to a board, or Preserve with 80% alcohol and 20% water Adult flies Eggs Largest larvae Forensic Science II: Forensic Entomology, Chapter 12 © 2012 Cengage Learning. All Rights Reserved

Temperature Readings Ambient air Ground Soil 1 foot above the body 4 feet above the body Ground Soil Surface 10 centimeters below 20 centimeters below Center of a large infestation (if present) Forensic Science II: Forensic Entomology, Chapter 12 © 2012 Cengage Learning. All Rights Reserved

Forensic Science: Fundamentals & Investigations, Chapter 11

Applications Time of injury vs. death Estimation of time of death Whether or not a corpse has been moved Instances of insects as weapons Child and elderly abuse and neglect Single vehicle car accidents

Applications “Roach Track” Confusion Roaches are notorious for confusing blood spatter analysis Blood trajectory is often critical to forensic investigations Roaches, silverfish and other household insects often travel through bloodstained areas

Applications: Insects and Illegal Drugs Shipments of illegal drugs often contain insect infestations, especially cannabis and heroine (derived from poppy plants.) Analysis of insect “stowaways” can allow investigators to track country of origin, and in many cases the local area of cultivation. PMI used to detect illegal drugs/poisons in fly larvae (consumed from corpses)