The Nature of Science:

Territorial Behavior in Crickets

Paul Kelly

Mike McNabb

Todd Shattuck

Overview

Cricket behavior during courtship is a useful tool in teaching students the importance of observation in biological sciences. Proper observational technique and principles of experimental design will prove necessary as students record the behavior of five crickets, three males and two females. Observing cricket behavior will also confirm that data collection during scientific research is not always exact, uniform or easily quantified. Using the methods of science, students will measure the number and types of interactions between household crickets (Achetus domesticus). Students will discriminate between quantitative and qualitative observations, and use collected data to develop hypotheses and guide their own experimental design.

Biological Concepts

• Scientific Processes

• Insect Behavior

Class Time

Approximately two-three 55 minute periods

Background Information

Crickets are classified in the following way:

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Orthopthera

Family: Grylleae

Genus: Achetus spp.

Male crickets are territorial, and after establishing their territory will defend it against other male crickets. According to Alexander and Simons (1961) there are five levels of aggressions in crickets:

The presence of a female cricket inside a male’s territory will increase aggressiveness toward other males, as well as stimulating courting behavior towards the female. However, the territorial behaviors in males will vary. These behaviors include:

•

• chirping

• wing flaring

• avoidance

• biting

• pushing

• guarding

Courting behaviors in males also vary. These behaviors include:

•

• antenna stroking

• chirping

• following

• guarding

Females also show specific behaviors, which include

• ovipositor insertion

• mounting of males

Male and female crickets show a strong sexual dimorphism (see Figure 1). Note the female crickets can be identified by long ovipositors that project from the tip of their abdomens.

Materials

(per lab group of four)

• One cricket terrarium with lid

• One isolated male housed several days prior to activity in terrarium (see below) (isolated male crickets will be marked with a single white dot on thorax)

• Two female crickets separated from male crickets

• Two male crickets separated from female crickets (these male crickets will be marked with either a red or blue dot on the thorax)

• metric ruler

• magnifying glass (optional)

Teacher Prep

At least ten terrariums should be prepared prior to obtaining crickets.

- Terrarium can be made from a clear storage container approximately 8"x 8" x 14" with lid.

- Bottom of container should be filled with sand approximately 1" in depth

- Place a piece of cardboard egg carton in the terrarium to serve as cricket shelter

- A piece of apple, oats, and/or dog food will provide food source

- Water on sponge or paper towel (use care not to make terrarium too humid; high humidity will damage or kill crickets)

Approximately five days before activity, teacher should obtain crickets from biological supply company, or local bait shop. Each lab group will need five crickets (three males and two female). Classes of 30 with 8 lab groups of three or four should require about 60 crickets.

Immediately upon receiving the crickets, they should be sexed (see Figure 1) and separated into male and a female terrariums. In the remaining eight terrariums, a single male should be placed in the terrarium so that he can establish his territory within the terrarium prior to the activity.

Isolated males should be marked with a single white dot (acrylic paint or correction fluid) on their thorax so that they can be easily identified during interaction with other crickets on the day of the activity. The other male crickets can be marked with either red and blue dots. Females do not have to be marked due to their distinctive ovipositor.

Crickets should remain isolated for 3 to 5 days. Feed crickets dog food, apple or oats.

On the day of the activity, allow students to proceed through the activity as written on the student handouts. The activity will happen in four steps:

Step I

• Groups make observations of single male in terrarium

• Groups discuss their observations with teacher facilitation.

• Teacher introduces importance of qualitative and quantitative observations using student data. Examples of qualitative data may include eating, hole digging, hiding. Examples of quantitave data include number of chirps, loudness of chirps (decibels), area covered by the cricket within terrarium.

Step II

• Groups choose whether to introduce a male or female cricket into the terrarium and make a hypothesis regarding their expectations of what will occur.

• Groups make observations.

• Groups report data and establish a behavioral key (Figure 2) outlining different behaviors (male to male, or male to female).

Step III

• Groups introduce another cricket of the opposite sex from the cricket they introduced in step two. This will ensure each group has two males and a single female in the terrarium. Groups make observations, using and modifying the key outlined in Step II.

• Groups report findings to class.

Step IV

• Groups make hypothesis regarding cricket behavior if an additional male and female are introduced to the terrarium (total of 5 crickets). Groups add a male and female cricket.

• Using chart provided and key made in class, groups will chart all interactions.

• Students organize data, and discuss further/unique experimentation with crickets.

Extensions/Variations

Students will be encouraged to design their own experiments regarding cricket behavior. Some possibilities for this experimentation include:

• How do environmental factors (light, day length, heat, etc.) affect cricket behavior?

• How do males crickets identify females?

• Are female crickets territorial?

• How would a territorial male react if placed into a new territory?

• Is chirping different in male-male interactions as opposed to male-female interactions?

Resources

Alexander, Richard D. & Simons, L.W. (1961) "Aggressiveness, Territoriality, and Sexual Behavior in Field Crickets," Behaviour, 17, 130-223

Cricket drawings taken from World Wide Web Site, "http://www.life.uiuc.edu/ Entomology/insectgifs.html"

Alcott, John, Arizona State University. Lecture at Woodrow Wilson Foundation Neurobiology Institute, Princeton, New Jersey, 7/96.

About The Authors

• Paul Kelly, Park Hill High School, 7701 NW Barry Road, Kansas City, MO 64153 [pvkelly@primenet.com]

• Mike McNabb, Ballard High School, 6000 Brownsboro Road, Louisville, KY 40222 [mikemc4161@aol.com]

• Todd Shattuck, Garfield High School, 5101 East 6^th Street, Los Angeles, CA 90022 [tshattuck@lausd.k12.ca.us]

NAME: __________________________ DATE: ____________ PERIOD: __________

The Nature of Science:

Territorial Behavior in Crickets

Overview

Cricket behavior during courtship is a useful tool in demonstrating the importance of observation in biological sciences. Proper observational technique and principles of experimental design will prove necessary as you record the behavior of five crickets, three males and two females. Using the methods of science, you will observe and measure the number and types of interactions between household crickets (Achetus domesticus).

Materials

(per lab group of four)

• One cricket terrarium with lid

• One isolated male housed several days prior to activity in terrarium (see below) (isolated male crickets will be marked with a single white dot on thorax)

• Two female crickets separated from male crickets

• Two male crickets separated from female crickets (these male crickets will be marked with either a red or blue dot on the thorax)

• metric ruler

• magnifying glass (optional)

Procedure

1. For five minutes, make observations of the single male cricket in the terrarium. Avoid moving or banging terrarium. Write your observations below (use complete sentences).

2. After class discussion, choose either a male or female cricket to add to the terrarium. Make a hypothesis about what you think will occur between the two crickets. Write your hypothesis below. Make observations made from observing the crickets for 10 minutes.

3. From discussions with entire class, construct a "behavior key" (sample on right) from observations the entire class made during the cricket-cricket interaction. The entire class will use the same key.

3. Place a third cricket in your terrarium so that you have two males and a female. Use the key above to describe how each cricket interacts with the others. Discuss with class.

4. What do you think will happen if an additional male cricket and female cricket are added to the terrarium? Write in the form of a hypothesis.

5. Place a third male and second female to the terrarium. Chart interactions between each of the crickets in the chart below:

7. Summarize how the five crickets interacted.

8. How was the large group interaction different from the smaller group? Why do you think this is?

9. Why was it important to discuss your results with other groups? Would there ever be a reason when communicating with other scientists would not be beneficial?

10. What new questions about cricket behavior do you now have as a result of this activity?

11. Select one of the questions from above and describe how you might test it.

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