Activities
The three-week unit begins with a basic overview of the role of forensic entomologists. This unit provides closure to the monthly insect hunts and documentation that students will have participated in for the duration of the school year, and therefore this unit should take place in the last grading period of the school year. Students have caught, photographed, sketched, and released insects in order to become familiar with the local insect species, trends year-round, and possible life cycles of some species. For teachers who do not intend to conduct monthly catches, a class period or two within the unit may be modified to accommodate field days, and thus timing this unit to be taught in the spring also increases the likelihood of catching live, adult insects.
Lesson Set 1: Introduction to Forensic Entomology
Students will take guided notes, watch a video clip, and render two articles about a case in which insects were an essential component in a legal case. The preferred video clip is Mike Rowe’s Dirtiest Jobs: Bug Detectives (Season 7, Episode 8), however, many publically available alternatives would suffice20. Students use a “Quad Note” taking format, in which they systematically log key information, similar to Text Rendering. At the time of writing this curricular unit, the preferred article in which an insect species was used to identify a suspect is Lynn Kimsey’s 2007 Los Angeles Times newspaper article, The Case of the Red-Shanked Grasshopper21. An article about insect poaching is the article Butterfly Poaching referenced from American University (Washington, D.C.).
Supporting activities in this first week involve reviewing the forensic definition of evidence and how it is assessed, learning the insects presented in the video and article, discussing the differences in life cycles between types of insects, and recognizing scientific names. Students will participate in the “Silent Witness” activity, in which they rank a small plastic bag of evidence items (either fictitious or adapted from simulation of a real case) in order of seeming importance, of which each evidence bag will include at least one desiccated insect sample. Students record their findings in their lab notebooks, and receive credit for completion rather than agreement with the teacher’s opinion. The purpose of this ranking exercise is for students to have discussions with their small lab groups and practice articulating and defending ideas.
At the end of the week, the teacher should present options for a project related to the unit. The two basic options, described in the Project section of this unit, should be either to create a menu or order form for illegal collectors or to produce a field guide of local insects. Some students may opt to conduct a case study or produce a video documentary, and these are excellent options for highly motivated students, hence will not be described as part of this unit.
Lesson Set 2: Research and Documentation
Guided notes for the second week should introduce formal categories of insects, with special attention to the nomenclature using genus and species, and the taxonomic order. Students should examine several Coleoptera (beetles), Hymenoptera (ants/bees/wasps), Odonata (dragonflies), Mantidae (mantids), Hemiptera (cicada), Blattodea (roaches), and Diptera (flies and mosquitos). Using the insects that lab teams have caught, groups will be able to categorize insects by order, and then further divide them into as specific a taxonomy group as possible. Student teams should expect to catch and observe a minimum of thirty specimens, of which most will be released into the area of the campus from which they were caught. With discussion in lab groups, students next agree upon a range of variation for each of the species of insects that they can define as a team. For example, the number of spots on a ladybug indicates a species; however, minor variations among each of the ones that have the same number of spots should be determined, documented, and defined. In learning taxonomies, students will also compare images of international species that are similar but different to their local key. Although not especially important in forensics, ladybugs are fairly common across the United States, and students should know that the spots on ladybugs are indicative of different species, not age or sex of the insect. For more information regarding citizen science regarding ladybugs, students can access the Lost Ladybug Project website.22
In researching their catches, students will find that their collection represents the regional species. Students may observe anomalous specimens, such as if they were very similar to the expected local species yet exhibiting a feature that makes it stand out as very different. An example would be finding a flying cockroach rather than the typical crawling type. The students will need to decide whether these are invasive species or whether it is a member of another population that has crossed some geographic borders. I suggest preparing a regional list or a website that documents local species. Several of these may be available from local universities, such as at the San Jose State University (SJSU) Entomology Collection and Museum. Depending on timing and access, teachers may invite a local entomologist to share his or her collections with the class. In the past, I have invited Carlos Stephens, a representative of SJSU’s Entomology Museum, and serendipitously, he is a graduate from my students’ high school district.
Lesson Set 3: Expert Witnesses
The third week combines the tasks of the two former components. Students will practice a skill learned in the first semester regarding scale factor by calculating the actual size of an insect using comparison to a reference in the photograph, such as a standard United States coin. After this exercise, teachers should pose a question in which the Elytra beetles are bred so that their elytra (wing covers) can be harvested for use in ornamental jewelry. These captive-bred insects are contrasted against a similar practice that involves poaching and illegal import/export of endangered beetles with beautiful wing coverings. Students will keep this question in mind throughout the week.
The final component of the lesson set is for students to testify as expert witnesses in an excerpted form of mock trial keeping in mind the context of the Elytra beetles. An expert witness is a person who has a specialty in a particular field and as such can explain evidence findings. An expert witness in entomology should thus be able to provide background about the role of insects in general as well as specific to the case. The distinction should be clear that an expert witness is not simply a person who has seen many crimes, but rather he or she is a subject-area specialist who is able to testify to provide detailed analysis based on evidence submitted to him or her. Selected students respond to questions regarding their profession, justify their identification of given insect specimens, and defend the reliability of possible evidence as studied. In these simulations, students are assigned roles as expert witnesses. In preparation, students should select a university affiliation of their choice, state their degree title, and respond to questions. The sets of questions will range in depth of knowledge, from factual information to inferences, predictions, and rationalization.
Culminating Project Options
To complete the extended assignment supporting this unit, students have the option of either creating a menu or a field guide. The project options are fairly flexible, however, teachers may need to restrict choices or provide more guidance depending on their own students. The basic scoring guide for either task is the same in that students must include accurately drawn or photographed (not downloaded) images, taxonomies (order, genus, and species), and provision of additional facts.
The menu could range in creativity from a fictitious local insect restaurant to creating an “order form” for commonly poached insects with alternatives based on common local species. It should resemble an actual menu as though from a restaurant, including a title, accurate images, and scientific names. Prices, such as the fetching price for illegal trade or the price associated with prosecution, should also be included.
Making a field guide involves researching the species and their forensic uses, if any. The field guide will explain the usability of the insect species in a forensic case. For example, is there minimal variation within the regional population of insects? If so, then it could be highly useful to find a representative of the species that is very different since that would indicate it is likely from a different location. Blowflies are also highly useful to forensic entomologists; their life cycle is well-documented and can fairly reliably predict the day when a corpse was introduced to the environment. A species very common in the region would be less useful than one that does not live in the wild in the region.
Lesson Differentiation
Each component of the unit may be differentiated to accommodate various student needs. For instance, the minimum number of notes may be set higher or lower depending on student English proficiency. Teachers may choose articles based on news stories that are more local than the ones I use in my lessons. Allowing students to select articles may also increase their ability to select credible articles from reliable sources.
Once the project has been assigned, teachers may opt to provide work time for students during class in order to monitor progress or to schedule time to check in with students. This may be particularly helpful if the students will complete the projects in small groups or if students generally do not have computer and internet access outside of school.
An option to differentiate the Expert Witness activity, especially for students who have educational accommodations related to oral presentations, would be for students to compose a written evidence report instead of orally testifying. An evidence report formally summarizes the findings from analysis of a specific sample retrieved from a crime scene, typically in comparison to reference samples. Writing evidence reports exercises analytical writing skills of students. The task also refines formal writing performance since information must be conveyed using neutral word choices that deliver information that may be used for legal assessment. For example, students are guided to avoid using terms such as “match” and “guilty”. Alternative terms to describe a “match” could be “consistent with the reference sample” or “the evidence sample cannot be excluded.” The purpose of composing an evidence report is to present objective information through which pieces must be combined during court discussion. True (real life) evidence reports may span several pages, but I assign a 200-word maximum to encourage succinct yet thorough analysis.
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