True accuracy of our textbook

Forensic Entomology is the study of insects to criminal matters. If we know how long it takes for an insect to mature, we can try to figure out the post-mortem interval. Forensic Entomology can be very reliable. Insects can provide detailed information about the time of death; bugs can go to a body within minutes and lay eggs.

     Most commonly used insects in forensic entomology is the blowfly. The blowfly is one of the first insects to arrive to the dead body. The fly goes into different stages so the life cycle is very informational. The blowfly goes through each stage and you can trace back the time each stage was present to help find out the death date.

     The book states that each stage will last a little bit longer than the previous stage. For the egg, it claims to last 8 hours and then the larva 1, 20 hours, larva 2, 15-20 hours, larva 3, 20 hours, the pre-pupa 3-4 days, late pupa between 6 and 12 days, and lastly, the adult fly takes weeks. I believe the flies in our experiment will not move through each stage so fast. I think that it will take at least a day for each beginning phase like the eggs and larva, 1 & 2 to complete. Hours is a short amount of time for something to mature, even though it is an insect, I believe the process will be slower than the books rate, but then be more accurate towards the last few stages.

For each individual group, we put our chickens in a small container and then put them in a bigger one,img_1836

so the flies could get to the raw meat, we cut holes into a container.


Throughout the experiment, we took pictures, and wrote down our observations and the progress of the experiment:

Days Weather Stage of Life cycle Observations
Day 0 On 9/29, the weather was dry and it was sunny.

High – 84

Low – 64

There is nothing going on around the chicken yet. The chicken was “fresh” and we put it into our own container then into the big container with holes on the sides to allow the flies to get in.  
Day 1 On 9/30, the morning was cool and fresh but there were no clouds.

High – 81

Low – 59

There are eggs already beginning to pop up. Already, the chicken began to smell. Eggs were laid and  there were adult flies buzzing around going from chicken to chicken. It still smelled like rotting chicken.
Day 5 On 10/4 it was humid and hot.

High – 91

Low – 88

Larva begins to make  it’s way around the chickens. The smell began to die down and there was a lot of dead flies in the big container and each little container. The chicken looked more exposed to the outside and flies but there was nothing new as in pupa.
Day 7 On 10/6 it was partly cloudy and the sun was peeking through.

High – 86

Low – 75

Pupa are now visible and measure at .9 of a centimeter. The stench was not nearly as bad as the other days. If you really tried to smell the chicken then you would be able to but it wasn’t bad. Pupa were now showing up and put into small containers. The pupa measured at .9 of a centimeter
Day 12 On 10/11 the weather was hot and it was sunny, but now the pupae were inside in little containers. The room temperature varied between 75 and 77 Pupae is now secluded and in their own space together. Everything looked the same as the pupa were still in their own containers and we waited for the flies to hatch. The pupa stayed at .9 of a centimeter.
Day 14 On 10/13 it was cloudy but everything was inside still, the temperature stayed  the same between 75 and 77 Adult flies are now flying around on day 14. There were adult flies this day. There was a container with a dead fly but there was also moving/ alive adult flies in our presence.

Thursday, Day 0, Sept. 29:

Friday, Day 1, Sept. 30:

Tuesday, Day 5, Oct. 4:

Thursday, Day 7, Oct. 6:

Tuesday, Day 12, Oct. 11:img_1947

Thursday, Day 14, Oct. 13:



In conclusion, my hypothesis was not correct. I thought the life cycle would be a slower process but that was not the case. For the books case, it was also incorrect, it stated that the process would be slow, but quicker than my thoughts, in the end, it was a quick process actually.  If I were to redo this experiment, I would check on the growth everyday to make sure I didn’t miss anything. I have learned that you cannot rely on just resource to get all your information from. Not everything is dependable and sometimes you have to look and observe for yourself.

Image result for chart on forensic entomology


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