Forensic Entomology Notes on page 79

What is Forensic Entomology?  Applying the study of insect life cycle to estimating time of death  Flies and beetles follow a life cycle that allow scientists to estimate how long a body has been deceased

Life Cycle of the Fly Soon after death 1.8 days 2.5 days 4-5 days 8-12 days days

The egg  Shortly after death, a mature fly will lay eggs on the decomposing flesh  Will typically lay eggs in moist, warm areas  Mouth, eyes, ears, anus, wounds  Will remain 8 hours  Approximately 2 mm in length

Larval stages  Also called instar 1, 2 and 3  Have black mouth hooks  Will have spiracle slits near anus  Instar 1: 1 spiracle slit; 5 mm in length  Instar 2: 2 spiracle slits; 10 mm in length  Instar 3: 3 spiracle slits; 17 mm in length  Crop visible in 2 nd instar stage; covered by fat deposits in 3 rd instar stage

Maggots

Pupa stages  After 3 rd instar maggots have matured, they will crawl away from body to a dry area  Become immobile, do not eat, changes to a dark brown color, pupa case is hard  Can stay in pupa cases for days

Adult flies  Adult fly matures in approximately days  They will be alive for several weeks  Not able to fly in first couple of hours

Beetles  Beetle larva differ from maggots in that they have 3 pairs of legs  Arrive on body after flies lay eggs  Come to feed on the maggots

Question  Answer this question on page 78  Explain how flies and maggots are used to help estimate the time since death of a decomposing body