Biomimicry of Ormia’s Ears

This activity is intended for a high school audience in a biology class, but can be modified for a middle school or elementary class.

Time Frame
Set-up: 5-10 minutes
Activity: 95 minutes
Clean-up: 5-10 minutes

After completing the activity, students will be able to:

  1. Gain a basic understanding of how ears work
  2. Imagine engineering designs inspired by biology

Standards Addressed
HS-ETS-ED Engineering Design
d. Plan and carry out a quantitative investigation with physical models and prototypes to develop evidence on the effectiveness of design solutions, leading to at least two rounds of testing and improvement.

Activity Materials
Part 1:

  • Ear Building Materials: Cardboard, tubes, cups, clay/putty/PlayDoh, fake fur/cotton
  • Scissors
  • Tape/Glue
  • Ruler
  • Sound Generating Device: Timers, LabQuests

Part 2:

  • Demonstrative Model of Ormia Ears
  • Photos of Ormia Ears

Part 3:

  • Decks of Biomimicry card game

Activity Instructions
Set-up 10 minutes

  • Lay out materials for ear construction and experiment.
  • Have Ormia ear model on hand and computer images of fly.
  • Have decks of Memory cards for each pair/group.

Introduction (5 min)
Begin with a discussion to find out what the class knows as a whole and reveal the objectives of the lesson. The following is a potential script for the teacher:

What do engineers do?
Our goal for today will be to find a link between biology and engineering, how biology can help engineers. The feature in biology we will be exploring is ears.

Students can respond to these questions verbally. Hand out guided inquiry packets. Allow collaboration as students work through each part. Discuss (in pairs/groups or as a class) #1-7.

Part One of the Activity 50 minutes
Prepare students to answer questions about what makes ears effective. They should answer their questions by constructing different ears and testing them. Together, the class should come up with the methods to answer the questions, the constants in the construction of ears, testing one variable at a time, the procedure for the experiment, a way to collect data…guided by the teacher.

Together we will design an experiment that we can do as a class. Each group can test a different feature of ears. We have timers/LabQuests that can generate sounds to listen for with each ear. Here are the materials you can use to build ears. Each group will create ears that test a certain question. Then we will share our results. What are some ideas you have about what makes ears effective? (Larger ears are better) One group could test length of ears, which is better for hearing long ears or short ears? Wide or narrow? What material is best (plastic, Styrofoam, paper, metal)? What surface is best (smooth, ridged, hairy)?

What would the independent variable be for group 1 (long vs. short ears)? (length of ears) Dependent? (how well they work) Constants? (materials, width) For group 2? 3? 4?

Put students in groups and have them construct ears.
The groups could look like this:
Group 1: Long vs. Short Ears
Use the same type of cardboard to create 3-5 tubes (ears). They should have the same diameter. Each one should be a different length.
Group 2: Wide vs. Narrow Ears
Use the same type of cardboard to create 3-5 tubes (ears). They should have the same length. Each one should have a different diameter.
Group 3: Materials – Plastic vs. Paper vs. Styrofoam
Use the same size cup to create ears from 3 different materials (ex: use 12 oz cups for each material). The same size hole should be cut in the bottom, center of each cup.
Group 4: Surface – Smooth vs. Hairy vs. Ridged Ears
Use the same type of cup for each ear (ex: use all paper cups). Leave one cup with a smooth surface. Use putty/clay/Play Doh to create ridges on the inside of one cup. Stick fake fur/cotton to the inside of one cup. The same size hole should be cut in the bottom, center of each cup.

We also need to agree on a procedure. Brainstorm with your partner steps for this experiment. What do you think should be the first step? Did anyone think of a step that could go before this one? … How will we record data?

[Come up with procedure and data table. Since data is qualitative, a numerical scale may be used to judge the effectiveness of each ear. For example: their own ears would be a 0. Holding up a good set of ears could be a 1 or 2. A poor set of ears might be a -1 or -2.]


  1. Make predictions about which ears will work best in each category.
  2. Using the Audio Function Generator on the LabQuests, choose a tone with a specific frequency, or use timers.
  3. Listen to tone with your own ears. Record how well you can hear it.
  4. Listen to the timer with each type of ear. Record how well you can hear each ear.

Suggested Constants:

  • Length of each test
  • Distance and position of ears and tone
  • Specific tone (in Hertz)
  • Number of trials

Trial 1

Trial 2

Trial 3

No Ear

Ear 1

Ear 2

Ear 3

Now that each group has their ears constructed, assign roles to each group member:

Sound generator – sets timer
Measurer – measure the distance and tell the tester where to stand
Tester – test each pair of ears
Recorder – record what the tester reports in the data tables
Have each group follow the procedure with their sets of ears.

Now I’d like you to focus on directional hearing. [Blindfold someone, create a sound and have them point to where they hear the sound.] How do you think he/she knew where the sound was coming from? What is happening in their ears, in their brain?

Return to guided inquiry packet. Have students work through #8-10 collaboratively.

How can we test directional hearing? (Change the location of the tone. Have the tester wear a blindfold. See if they can detect, point to, where the sound came from. How far away was their guess?)

  1. Repeat the testing procedure agreed on previously, but change the location of the tone (while keeping the same distance from the ear).

Trial 1

Trial 2

Trial 3

No Ear

Ear 1

Ear 2

Ear 3

Which ears were most effective in the first experiment? Why?  Which ears were most effective for direction? Why? What kinds of animals need to hear direction? What do their ears look like? What features would be best for hearing direction?  Which animals need to hear for distance? What do their ears look like? What features would be best for hearing at a distance?

What made the experiment less credible?

Part Two of the Activity 15 minutes
Show a variety of pictures of the hearing mechanism in the Ormia fly. Discuss directional hearing in the Ormia fly using #11-14 in the guided inquiry packet and any available models.This fly is parasitic. It can hear crickets calling at night. It follows the call, lands on the cricket, and lays eggs in the cricket. The eggs hatch and eat the cricket. It has directional hearing that locates sounds within 2 degrees. What problems do you notice/ questions do you have about this fly’s ears? They’re right next to each other, connected, how can it detect the time difference that we detect?  It finds the direction of the sound by a lever/bridge than connect the ear drums. (Show pictures) The bridge that connects them creates a larger time difference. The new time difference is large enough for the fly’s brain to understand.

[try model demonstration]

This fly is tiny! It can’t figure out directions of sounds the way we can. It has ears that are connected so that it can find directions of sound. The lever changes the vibration. Engineers are very interested in this fly. Why? What technology could this be used for?

(Think-Pair-Share) This is what engineers are currently using Ormia’s ears for: microphones, hearing aids, satellite dishes

All of these use antennas. What is an antenna? Antennas pick up signals of electromagnetic waves. A transmitter puts out a signal (using an antenna) and a receiver picks up a signal (using an antenna). These parts can change sound waves and data waves into electromagnetic waves and back again. That allows wireless communication. What antenna technology do you use? Cell phones, tv, radio.

This summer I worked with some professors and students who were researching antennas. They learned about the Ormia fly and are trying to use what they learned from the fly in antenna technology. They are engineers. Many engineers get their ideas from biology, organisms. This concept is called biomimicry.

Part Three of the Activity (20 min)

Hand out a deck of Biomimicry cards to each pair/group and explain the game.

This game is essentially “Memory” or “Concentration.” There are biology cards with different organisms on them, which have a green background. Each biology card matches with a certain technology card. The technology cards are engineered products inspired by something in biology. *You may want students to find the pairs BEFORE playing the game, as some are difficult to discover through playing. (All cards are laid out in columns and rows face down. On a player’s turn, they flip over two cards, so everyone can see, then put them face down. The goal is to remember where each card is. One a player chooses two cards that match on their turn, they keep those cards. Each match is one point. The player with the most points when all the cards are gone wins.)

What was some interesting technology you learned about from this game?

Conclusion (5 min for explanation – take home activity)
Refer to #15-16 in the guided inquiry packet which asks students to invent their own idea of biomimicry. This can be a homework assignment so students can research interesting features of animals and implement one in technology.

Think of your own original idea of biomimicry. Think about some unique features of an organism and decide how it could be used to create new technology to improve existing technology. The assessment should include:

  • Background information about your organism and its special features. Why does it have this feature? How did it get this feature?
  • How it could be used in new technology or to improve existing technology. How will this help people?
  • A sketch/diagram to show what the technology might look like and/or how it would work.

Teachers should know some basic information about how sound waves work and how the human ear works. They will also need to know how Ormia’s ears work.

Supplemental Materials

  • A Guided Inquiry packet can help lead discussion and allow students to draw conclusions from pictures, diagrams, graphs.
  • A digital presentation can help guide the activity and provide visuals.

Biomimetic: Technology Imitates Nature. (2009, August 23). In Scienceray. Retrieved July 10, 2012
Biomimicry 3.8. (1999). Case Studies. Retrieved June 27, 2012 (2010). The 15 Coolest Cases of Biomimicry. Retrieved July 10, 2012
Christie, K. (2003, April 29). And the Flies Have it. Novel Auditory Mechanisms in a Parasitoid Fly. In Topics in Neuroethology. Retrieved June 27, 2012
Hoy, R. R. (1998). Comparative Hearing: Insects. New York, NY: Springer-Verlag New York Inc.
Miles, R. N., Robert, D., & Hoy, R. R. (1995, June 6). Mechanically Coupled Ears for Directional Hearing in the Parasitoid Fly Ormia Ochracea. Journal of Acoustical Society of America, 98(6), 3059-3070.
National Public Radio. (1999, July 12). Ormia’s Ear. In NPR Radio Expeditions. Retrieved June 27, 2012
Robert, D., Edgecomb, R. S., Read, M. P., & Hoy, R. R. (1995, December 2). Tympanal Hearing in Tachinid Flies (Diptera, Tachinidae, Ormiini): the Comparative Morphology of an Innovation. Cell and Tissue Research, 284, 435-448.
Robert, D., Hoy, R. R., & Miles, R. N. (1998, June 23). Tympanal Mechanics in the Parasitoid Fly Ormia Ochracea: Intertympanal Coupling During Mechanical Vibration. Journal of Comparative Physiology A, 443-452.
Seven Amazing Examples of Biomimicry (2010, February 8). In Improve Your World. Retrieved July 10, 2012

Additional References
Extensions: This activity lends itself to many other topics including:

  • Coevolution (between the Ormia fly and crickets)
  • Symbiosis (Ormia’s parasitic relationship with crickets)
  • Sensory systems (how the vibrations of sound are transferred to neurons)
  • Waves (sound waves, electromagnetic waves in wireless communication, frequency, amplitude)
  • Engineering (improve technology)

RET Fellow:  Kira Jacobson
RET Leadership Team: RET Teachers, Ben Taylor, George Lisensky, Nader Behdad, Amir Masoumi, and Anne Lynn Gillian-Daniel.