Pill Bug Behavior Choices
A Carolina EssentialsTM Investigation
Total Time: Ihr 30mins
Prep: 1hr 30 mins | Activity: 45mins
Life Science
6-12
Middle/High School
Overview
Three concepts are paramount to understanding weather basics: temperature, pressure, and the Coriolis effect. Air temperature and pressure affect the density of an air mass. Differences in density set up convection currents that move air both vertically and horizontally within the atmosphere. Convection currents lead to pressure gradients that drive air across the surface of the earth, and the Coriolis effect explains apparent deflections in direction. Meteorologists report parameters such as temperature, air pressure, wind speed, and wind direction. These concepts can be demonstrated quickly and visually for students in an introductory demonstration or small group activity at the beginning of a weather unit.
Essential Question
Do environmental conditions affect animal behavior?
Investigation Objectives
- Investigate how pill bugs respond to humidity levels in their environment.
- Identify 2 other environmental factors that influence pill bug behavior.
Next Generation Science Standards* (NGSS)
SCIENCE & ENGINEERING PRACTICES
Constructing Explanations
- Students will construct and revise an explanation based on valid evidence obtained from the investigation.
DISCIPLINARY CORE IDEA
LS2: Ecosystems: Interactions, Energy, and Dynamics
- LS2.C: A complex set of interactions within an ecosystem can keep its numbers and types of organisms relatively constant over long periods of time under stable conditions.
CROSSCUTTING CONCEPTS
Cause and Effect: Mechanism and Explanation
- Students can suggest cause and effect relationships to explain and predict behaviors in complex natural systems.
Materials
- Pill bugs
- Choice chambers (2 chambers)
- Filter paper or circles of paper towel
- Dropping pipets
- Potting soil or premium garden soil
- Pail with lid
- Beakers or cups for water
- Springwater, deionized water, or tap water treated to remove chloramines
- Plastic spoons
- Stopwatches (preferred), watches with second hands, or smartphones with stopwatch applications
Safety and Disposal
Ensure that students understand and adhere to safe laboratory practices when performing any activity in the classroom or lab. Demonstrate the protocol for correctly using the instruments and materials necessary to complete the activities, and emphasize the importance of proper usage. Use personal protective equipment such as safety glasses or goggles, gloves, and aprons when appropriate. Model proper laboratory safety practices for your students and require them to adhere to all laboratory safety rules. Return the pill bugs to the pail. Throw filter paper in the trash. Clean out the choice chambers and return them to the designated place.
Procedures
If you ordered pill bugs from Carolina, immediately open the shipping container upon receipt and check their condition. They are shipped in damp paper towels to provide the humidity they require. If the paper towel is not damp, add just enough water to remoisten it. After examining the pill bugs, close the container. If you use the pill bugs right away, no additional care is needed. If you need to keep them for more than a day before use, prepare a holding container. Punch air holes in the lid of a pail, cover the bottom with moist potting soil, and place a slice of raw potato or apple on the soil. Mist the inside of the pail with room-temperature water. Gently empty the contents of the shipping container into the pail. Carefully unfold the crumpled paper towel and shake off as many of the pill bugs as possible. If you are unable to dislodge all the pill bugs, use a soft artist’s brush to remove any that remain. Mist the inside of the pail again and replace the lid.
Pill bugs need little care other than humidity and food. At the end of this lab, return the pill bugs to the container. Feed them leaf litter and pieces of potatoes, apples, or carrots. Immediately remove any food that becomes moldy. This provides what the pill bugs need to thrive and even to reproduce.
STUDENT PROCEDURES
- Place a clean sheet of filter paper or paper towel disk into each side of the choice chamber.
- Using the dropping pipet, dampen the filter paper on 1 side of the chamber. Make sure the paper absorbs all excess water.
- Use a plastic spoon to transfer 5 pill bugs to each side of the chamber.
- Put the lids on the chamber.
- Count and record on the data table the number of pill bugs on each side of the chamber every 30 seconds for 10 minutes. Continue to record data even if they all move to 1 side or stop moving.
TEACHER PREPARATION AND TIPS
- If you collect your own pill bugs, follow the care instructions listed above.
- Go over the essential question and objectives with students prior to performing the experiment.
- Explain and show students how to safely handle the pill bugs
- Demonstrate how to connect the choice chambers
- Explain “damp.”
- If permissible, students may use smartphones as a timer.
- Demonstrate how to transfer the pill bugs without dropping them.
- Make sure all pill bugs are returned to the stock pail. If you collected them outside, they may be returned to the same spot.
Data and Observations
Sample Table
Analysis & Discussion
- Graph your data for the damp side and the dry side of the chamber on the same axes. Title the graph and include the following information:
a.The independent variable is time.
b. The dependent variable is the number of pill bugs in each chamber.
c. Plot the independent variable on the x-axis and the dependent variable on the y-axis.
Explain how the pill bug response to humidity may be advantageous.
Pill bugs respond to a moist environment because they breathe through gills. This allows them to live and reproduce, continuing the species.
Based on your graph and the introductory material, explain pill bug behavior with respect to humidity.
From 30 seconds on, there were more pill bugs in the damp chamber than in the dry chamber. From 7 minutes, 30 seconds through the end of the data collection, all 10 pill bugs were in the damp chamber. Pill bugs are crustaceans and breath through gills. They must have a moist environment to survive.
Identify 2 more environmental factors that may affect pill bug behavior.
Temperature, light intensity, substrate texture, substrate color
Design an experiment to test 1 of the environmental factors that may affect pill bug behavior.
Answers will vary. Make certain students are testing 1 variable at a time and have a way to quantify the data. A setup similar to the one in the main activity is acceptable.
SHOP THE KIT
SAFETY REQUIREMENTS
- Safety Gloves Required
- Safety Goggles Required
HELPFUL LINKS
VIEW MORE ESSENTIALS
*Next Generation Science Standards® is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of, and do not endorse, these products.
