Forensic Entomology – Using insects to assist in time-of-death analysis

Egg to Adult… about 2 weeks depending on Temperature and Humidity…

2 – Eggs hatch into larva (maggots) in 12-24 hours 1 – Adults lay eggs on carcass at wound areas and/or body openings (nose, eyes, ears, anus, etc.) 2 – Eggs hatch into larva (maggots) in 12-24 hours 3 – Larvae continue to grow and molt (shed exoskeletons) through the various stages. 1st Instar - 5 mm long after 1.8 days 2nd Instar - 10 mm long after 2.5 days 3rd Instar – 14-16 mm long after 4-5 days 4 – The larvae develop into pupa after burrowing in surrounding soil, after 4-5 days. 5 – Adult flies emerge from pupa cases after 6-8 days.

Decomposition of a baby pig https://www. youtube. com/watch Professor from University of Michigan https://www.youtube.com/watch?v=PLJsXnTIS6Q

STARTS after 1-2 hrs “FULL” after 8-12 hrs ENDS: after 24-48 hrs Rigor Mortis STARTS after 1-2 hrs “FULL” after 8-12 hrs ENDS: after 24-48 hrs

Rigor Mortis: “Stiffness of Death” PATHWAY eyelids  jaw  face  torso  limbs Relaxes in the same order

Algor Mortis: ‘Coolness of Death’ Beginning at 37⁰ C, body temperature drops steadily Systems which maintain HOMEOSTASIS not working Taking temp of corpse…rectal (best) or armpit. Mouth muscles relaxed (or Rigored) …tongue won’t stay on top of thermometer. Thinner people cool faster than fat.

Livor Mortis: “Color of Death” Heart stops = blood stops cycling RBCs and plasma gravitate to lowest point

STARTS: after 1-2 hrs “FIXED”: after 6-8 hrs -- body position may not agree with lines

Vitreous Humor Not much? Cloudy? Broken blood vessels? = Dead longer… Cloudy? Broken blood vessels? = likely strangulation

When Did She Die ? Anatomy & Physiology Homeostasis = “steady state” hypothalamus pituitary cells making ATP ATP allows muscle cells to contract and relax. Your cells can store some, but not much… The last little bit is probably used up in Rigor Mortis – the final contraction

When Did She Die ? Anatomy & Physiology