Teacher Information

Light My Fire ...Fly

Elizabeth M. Dann

Overview

In this activity students will measure the frequency of light stimulus used by communicating fire flies. This activity is used to introduce the topic the concept of using light to communicate in many organisms. A VCR with frame advance capability is required in order to quantify the duration of the light stimulus.

Biological Concepts

• intraspecific communication

• nature of light

• animal behavior

• structure of the compound eye/human eye

Class Time

Students will need to get film footage at dusk of fire flies.

One 50 minute class period is required to analyze the data.

Background Information

Many organisms use light as a venue for communication. This phenomenon was noted as early as the 4th century B.C. by Aristotle. In the 1st century A.D. the Roman statesman, Gaius Plinius Secundus, wrote about bioluminescent fauna in the Mediterranean Sea. Bioluminescence has been studied in both aquatic and terrestrial organisms. Organisms that can be studied include bacteria, protozoa, jellyfish, corals, sharks, insects, crustaceans, and fungi.

Light can be generated in one of three ways in organisms:

a) extracellular organisms are able to secrete chemicals into the sea around them.

e.g.. shrimp, squid

b) some organisms secrete substances that cover their outer bodies.

e.g.. these organisms are not well studied

c) organisms are able to secrete chemicals intracellularly

e.g.. cephalopods, insects, fish, crustaceans

In most species, the chemical luciferan is responsible for producing bioluminescence. This chemical is controlled by the enzyme luciferase which is controlled by the central nervous system. Luciferan is found in the visible light spectrum between 415 - 670 nm.

There are many species of fire flies which generally fall into one of the following genera, Coleoptera, Lamyridae, Pteroptyx, Luciola, Phausis, and Photinus. Fire flies use bioluminescence to promote mating, illuminate landing sites, as a form of aggression (including predation), and defense. In the clear majority of these behaviors, timing is used to communicate and only in rare cases is the shape of the "flash" responsible for communication.

The frequency and intensity of luminescence can be used to distinguish species and gender in mating fire flies. The following chart can be used for species identification according to the duration of the "flash".

Species female flash (seconds) male flash (seconds)

Photinus macdermotti 3.2 0.2-2.2__________________

Photinus greeni 2.2 0.2-1.2__________________

Photinus pyralis 2.2 0.2 or_6.2_______________

Photuris versicolor 2.0 or 7.0 6 flashes in 1second________ Photouris lucicrescens 3.0 2.0 ____________

Luciola aphrogeneia 2 flashes a second for 4 sec.__ 3 flashes a second for 4 sec._

Phausis reticulata glow from 4-7 seconds indefinitely long glow______

Lampyris noctiluca continuous glow does not glow____________

(adapted from Case, J.R. 1984)

Materials

• video recorder

• video tape

• VCR with frame advance capability

• fire flies

Teacher Preparation

Student groups should be instructed to take video footage of flashing fire flies for approximately 5 minutes.

1. Count the number of frames that a "flash" lasts for using the frame advance control.

2. Determine qualitatively where the flash is coming from with respect to the ground.

3. Flash length can be calculated by multiplying the number of frames by 33 milliseconds.

Extensions/Variations

Experiments can be designed that test the effects of drugs and temperature on the pattern of bioluminescence.

The ability to measure frequency by using the frame advance control is a tool that can be used in a variety of experiments. Some examples include breathing mechanics of fishes and reflex behaviors.

Resources

Buck, J.B. and E. (1980). Flash Communication as tool and as enabler in firefly courtship competition. Am. Nat. 116, pp. 587-590.

Case, J.F. (1984) Vision in Mating Behaviour of Fireflies in "Insect Communication" (T. Lewis, ed.). pp. 195-222. Academic Press, Harcourt Brace Jovanovich.

Hailman, Jack. Optical Signals, Animal Communication and Light. Indiana University Press, Bloomington and London, 1977.

Johnson, Frank H. Luminescence, Narcosis, and Life in the Deep Sea. Vantage Press, New York, 1988.

Lloyd, J.E. (1977) Bioluminescence and Communication n "How Animals Communicate". (T.A. Sebok, ed.) pp. 164-183. Indiana University Press, Bloomington.

About the Author

Liz Dann is a Biology teacher at the Walnut Hill School in Natick, Massachusetts. She can be contacted by e-mail at edann@idea.uml.edu

Student Activity

NAME:_______________________________DATE:______________PERIOD:_____________

LIGHT MY FIRE ...FLY

1. List three reasons that organisms such as fire flies communicate through bioluminesence.

2. List the two main methods of light generation in oraganisms.

3. Name the chemical that produces light in most organisms. What enzyme controls this process?

4. Complete the following data chart after reviewing your film footage:

Trial Relative position to the ground #of frames # of milliseconds

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

5.Using the chart provided by your teacher, can you identify the species of fire fly that you filmed?

6. Are you able to determine if your fire fly is a male or a female?

Extra Credit: Using all available resources (internet,library, etc.) is it reasonable to expect your species of fire fly to be found in your geographical region?

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