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Biology LibreTexts

Investigation: Habitat Selection in Flour Beetles

  • Page ID
    20792
  • Overview

    In this laboratory, you will observe the behavior of an insect and design an experiment to investigate its responses to environmental variables.

    Objectives

    After doing this laboratory you should be able to measure the effects of environmental variables on habitat selection in a controlled experiment.

    Pre-Lab Questions

    1. What is meant by an environmental variable?

    2. What is meant by habitat selection?

    3. Provide two examples of variables you could test with any animal study.

    Examine sample data from an experiment on pillbug. The pillbugs were placed in the choice chamber, 5 on each side. They were then observed for 10 minutes and the number on each side was recorded.

    4. Graph the data shown and write a brief summary of what the data shows about pillbug behavior.

    Time(minutes) # In Wet Chamber # In Dry Chamber
    0 5 5
    1 5 5
    2 6 4
    3 6 4
    4 6 4
    5 7 3
    6 7 3
    7 8 2
    8 8 2
    9 9 1
    10 10 0
    Conduct Your Experiment

    Choose the variable you want to test from the following options. (Choose ONE)

    1. Wet vs Dry
    2. Water vs Vinegar
    3. Sand vs Paper
    4. Light Vs Dark

    5. Write a hypothesis about what environmental condition will be preferred by your specimen. Write the hypothesis as a complete sentence.

    Experiment Set-Up

    For this lab, you will use flour beetles. Set up your choice chambers to test the variable of your choice. Generally, filter paper or paper towels can be used to test chemicals such as alcohol and vinegar. Your instructor will have the materials you need. Each side of the chamber should have a different variable.

    beetle diagram.png

    6. Label the diagram to show how yours is set up.

    7. Collect Data: You will need to collect data for at least 10 minutes. A graph will not be necessary this time.

    Time (minutes) Side L Side R
    0
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10

    8. Summarize Data: Examine the data you collected and write a statement that summarizes the data and answers the experimental question (hypothesis.) This statement should be a complete and thoughtful sentence that is supported by the data you gathered.

    Instructor Notes:

    Choice Chambers available form Amazon or Carolina Biological Supply Company

    Cut filter paper in matching shapes to save time. You can just soak the filter paper before putting it into cage. Paper towels that aren’t flush with containers will likely result in the animals crawling under them.

    Students may need additional assistance with drawing the graph on the first page, I recommend a bar graph with colors indicated numbers on the wet and the dry side.

    Other animals can be used, I maintain a mealworm colony in my class to feed lizards and turtles. The adult beetles perform well in this experiment. You could potentially substitute crickets or have students collect pillbugs. I didn’t find the larval mealworms to be very good in this experiment, they seem to have limited senses and do not move very quickly.

    Beetles in choice chambers. Filter paper allows for changing habitat properties.

    beetle lab.png