Forensic Entomology Activities
Forensic entomology is applying the study of certain insects to help with criminal investigations. A forensic entomologist may be required to identify insects at different phases of their life cycle as well as collect and preserve insects as evidence at a crime scene. Studying insect evidence can help ascertain the time elapsed from the time a victim was killed to the time the victim's body is discovered. For students studying forensic entomology, there are several hands-on activities that can bring the subject matter to life.
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Murder Case
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The National Library of Medicine's website provides lesson details and information for a forensic entomology activity that uses details from a real murder case. The investigator in the murder case had to collect insects as evidence as well as raise larvae until they reached the adult stage of their life cycle. Students are given the role of detectives in this activity and will access the case summary which provides information of the detailed investigation. Students will then use reasoning and mathematics to answer worksheet questions and also show that they have grasped the concept of how information about insects' life cycles can be used to determine time of death. Keep the answers hidden and offer a prize to the budding detective who gets the correct answer.
Blow Fly Life Cycle Chart
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One of the most important insects in forensic entomology is the blow fly. This activity is for younger students and will help them to understand the stages of the blow fly's life cycle and how this relates to forensics. Students will need cardboard and drawing materials to create a life cycle chart. The adult blow fly lays eggs on a dead body within minutes of death. The eggs are laid in the body's natural openings and in any wounds. Each female blow fly lays about 250 eggs from which the first-stage maggots will emerge within 24 hours. Once they have fed and molted, they become second-stage maggots, and after feeding for a number of hours, they molt once more and become third-stage maggots. The final stage is metamorphosis into the adult form. This is an important timeline for students to understand and memorize. The sizes of the insect at different stages should be noted and labeled on the chart.
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Raising Flies
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It's one thing to learn from pictures and diagrams, but raising live flies is an activity that will help students to identify the real thing. This activity, which can get rather smelly, should not be done on a really hot day, as flies do not flourish in excessive heat. Place liver pate and baked sardines on separate foam meat trays. Set the trays outside in a lunch box on top of a layer of dry sand. The sand should be about an inch deep. Leave the trays uncovered for about two days. Hairy maggots, of the genus Chrysomya, will be attracted to the sardines, while smooth maggots, genus Calliphora, will be attracted to the liver. Once maggots are visible, bring the trays inside and cover with a netting material. Mist the food with water to keep it moist. Students can watch the maggots grow and change. They should keep a chart with measurements and observations.
Time of Death Game
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Insects arrive at a dead body at very specific times and in a particular order. They then continue onto different phases of their life cycle depending on the temperature and other factors. Divide the class into teams and have them read up the night before about the various insects involved in forensic entomology. Prepare a set of questions and scenarios that describe a crime scene and the insects present on that particular victim. Based on these clues, teams must work out the respective times of death. The winning team is the one that determines the answers the quickest.
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References
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