Behavior Lab
Pillbug Background
A pillbug, or roly-poly, is a greyish-brown crustacean that lives on land and consumes decaying matter like plants. They cannot live without water so they primarily reside in moist environments under rocks and wood. They have three general body parts: the head, thorax, and abdomen. Pillbugs breathe through gills, have a protective exoskeleton, and defend themselves by rolling into a ball. The female carries eggs in a pouch and the eggs are fertilized by the male pillbug's appendages. Generally, the female pillbug carries around 100 eggs in her pouch and the eggs hatch looking like their parents. Growth is done by molting and occurs several times before the pillbug reaches maturity.
Sources:
http://www.ca.uky.edu/entomology/entfacts/ef439.asp
http://insected.arizona.edu/isoinfo.htm
Sources:
http://www.ca.uky.edu/entomology/entfacts/ef439.asp
http://insected.arizona.edu/isoinfo.htm
Line Graph
Conclusion
1. What are the variables in this experiment?
The independent variables are the moisture present on the paper towels in the chambers and the time spent migrating through the chambers. The dependent variable is the number of pillbugs found in each chamber. The control is the middle chamber where the pillbugs choose which new chamber to enter.
2. What conclusion can you draw from these data?
From the data gathered, it can be assumed that pillbugs prefer environments with a greater concentration of moisture over dry areas. In this experiment, the pillbugs respond to stimuli by kinesis.
3. Do you think you would have seen the same trends if this lab was conducted with an earthworm? How are earthworms and pillbugs similar with respect to their behaviors? Why do you think they are similar?
If this lab was conducted with earthworms, the organisms would most likely respond in the same manner due to the earthworm's preference for a moist environment. Earthworms and pillbugs are similar in their behavioral responses because they both respond by kinesis rather than taxis. They are similar in this respect because they are both responsible for breaking down plants in the soil. Plants are usually located in moist areas so both organisms are most likely to migrate to the areas they can do their niche.
The independent variables are the moisture present on the paper towels in the chambers and the time spent migrating through the chambers. The dependent variable is the number of pillbugs found in each chamber. The control is the middle chamber where the pillbugs choose which new chamber to enter.
2. What conclusion can you draw from these data?
From the data gathered, it can be assumed that pillbugs prefer environments with a greater concentration of moisture over dry areas. In this experiment, the pillbugs respond to stimuli by kinesis.
3. Do you think you would have seen the same trends if this lab was conducted with an earthworm? How are earthworms and pillbugs similar with respect to their behaviors? Why do you think they are similar?
If this lab was conducted with earthworms, the organisms would most likely respond in the same manner due to the earthworm's preference for a moist environment. Earthworms and pillbugs are similar in their behavioral responses because they both respond by kinesis rather than taxis. They are similar in this respect because they are both responsible for breaking down plants in the soil. Plants are usually located in moist areas so both organisms are most likely to migrate to the areas they can do their niche.