Forensic Entomology Lab Report

Zachary Hamel

Advanced Forensics

Entomology Lab

10/2/14

          

           Our advanced forensics class established and created a lab to aid us in our study of decomposition and forensic entomology and the effect insects have on decomposition. On September 8^th, our class went into the front of Tolman in from of the Blackstone and dug a well sized hole. Next, we unwrapped the pork shoulder and placed it inside the hole, not too deep. We then placed a cage like covering over the pig shoulder, and used spikes rocks and some zip ties to make sure no outside variables or animals would come into contact with our pork shoulder and affect our decomposition and data. As soon as the pork shoulder was placed on the ground and left long enough without any disturbance, flies were migrating towards the body within minutes, and beginning to lay their eggs.

In the first couple of days that would pass, we had a minor heatwave, which could have possibly affected our rate of decomposition. We went outside to check on the shoulder each day, and saw little to no changes in appearance, or any insect activity. It wasn't until we went outside on September 10^th or around there, that we saw a notable difference. It was on this day that we could finally examine and analyze the notable insect activity on, in, and around the pork shoulder. There were now bees picking apart at the flesh and tissues, flies were still swarming around the crevices and open areas of the pork shoulder, and maggots had become present in and around the shoulder. They were eating away at the flesh little by little. It was also at this time, that the skin began to get very hard and stiff, and change color from a beige almost pink, to a green almost turning brown. We later went out around the 16^th or 17^th of the month to examine the shoulder again, and it was during this observation and analysis that we could see the maggots swarming all over and around the body seriously eating away at it, making the body decompose very progressively. The skin and shoulder at this time, or what was left of it, had turned a very dark brown almost blackish color, and the smell of it was almost unbearable, so much that Vick’s had to be applied to come within observing distance. The maggots had begun the third instar, or the third form a larvae before they begin to pupate.

At this time, it was time for our class to finish our observations of the pork shoulder and begin to collect, mark down, and analyze our data. What we were trying to do was analyze the information we took from the pork shoulder and the given insects around and on it, to find the PMI or post mortem interval, to try and see how forensic entomologists do these same tests to conclude when a body has died or been killed. We gathered data from the national weather information on average temperatures from each of the days we went outside and made our observations. The weather during this time could have played a major role in the case, as if it would have been hotter, the decomposition would have been thoroughly sped up, where as if it had been much colder the decomposition process would have been extremely slowed down. Comparing our data with the published data, our results were consistent with the published data, as the average temperatures for the time our pork shoulder was outside was pretty well matched up with the data we got from our analysis.

Forensic Entomology is a great tool and resource to have at your ability, as it can be highly beneficial to solving a crime and finding out the exact day that a body or in this case a pork shoulder, was dispersed of, and began to decompose.  It helps entomologists, and us students, understand the connection that flies, maggots, and all bugs have to a case and how valuable and critical they are in a case, where no evidence is left behind and there are no clues or answers. This lab also helped us to comprehend and understand what the life cycle of a maggot is like and how its different stages of life can all be useful and beneficial to a forensic case. In all, this lab truly showed us how valuable a small little insect like a fly or maggot can be to forensic entomology and to calculating the time of death.