Academic journal article Science Scope

Don't Swat That Fly! Using House Flies in an Inquiry Activity

Academic journal article Science Scope

Don't Swat That Fly! Using House Flies in an Inquiry Activity

Article excerpt

What do you think of when you see flies buzzing around? If you only consider swatting them, you are shooing away a valuable tool to use in your classroom. Most students have encountered insects either in their daily activities at home or outside in the school yard. Teachers can take advantage of this familiarity and easily use insects to introduce complex scientific principles. We have developed an activity related to house flies, Musca domestica (L.), that can be used in middle school science classrooms. The activity is relatively inexpensive to set up and emphasizes house fly biology and associations with humans, making this entomological theme easy to incorporate into numerous science topics (Figure 1).

The activity is centered around a series of "mysterious events" occurring in a fictitious town. Crime scenarios are inherently problem-based and thus provide a natural context by which authentic mysteries may be solved using an inquiry-based approach. See Figure 1 for standards addressed in this activity.

This activity would be appropriate for a study of structural adaptations or food webs in a life-science class or using experimental design to produce empirical evidence as part of a study of the nature of science. For students in a biology or environmental science course, it could serve as an introduction to entomology; in a life-science or health class, it could be an introduction to disease transmission.

What's the crime?

Crime scene: Spots on my white picket fence?

To introduce the crime, we created a newspaper that presented different stories concerning the town of Proximity Parish (see Activity Worksheet). One story interviews the park supervisor, who discovered that the freshly painted fence on Main Street had been vandalized. Another story describes the gelatin-eating contest that had been held earlier in the week. Finally, a third story is about the increasing number of house flies present along Main Street.

Students working in groups of four read and discuss the articles, using the Activity Worksheet as a guide to integrate information and develop their own hypotheses regarding the apparent vandalism. They should generate a prediction that the house flies were responsible for the polka dots on the white picket fence. If students do not generate this prediction, teachers can guide them to the conclusion that house flies might be causing the spots. The teacher then presents a variety of materials to students, including gelatin and house flies, that they can use to test their hypothesis. Student groups then make their plans for testing the hypothesis and share them with the class. After discussion, the teacher presents an experiment for solving the "crime." Through the experiment students will determine the following:

1. Whether house flies can feed on gelatin

2. Whether flies that have fed on gelatin of colors could be responsible for the discoloration of the white picket fence


1. Students will safely conduct a scientific inquiry to solve valid problems.

2. Students will describe adaptations/characteristics of the house fly that can be linked to disease transmission.


3. Students will be able to describe the role of house flies in the ecosystem.

Materials and teacher preparation

To rear house flies

House flies can be purchased from several biological supply companies. They should never be collected from the wild or released back into the wild after being purchased from a biological supply company. Approximately 300 house flies should be ordered for a class of 25 to 30 students, who will work in groups of four. The least expensive (~$30) and easiest option is to order flies in the pupal stage (the stage before adult) (Figure 2); however you will need to allow three to five days for the flies to emerge into adults. Pupae should be placed in a 250 mL cup that is then placed in a well-ventilated, screened cage. …

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