Thursday, April 3, 2014

Rollie Pollie Lab



 

 

 

 

 


 


 


 


 


Behavioral Tendencies of Rollie Pollies


Joe Rode


Honors Biology


4/3/14


 


 

 


 


 


 

 

 


 


ABSTRACT


            In this lab, we designed our own experiment to test certain behaviors of pill bugs. We discovered that pill bugs preferred completely dry over completely wet (dry vs. wet), no smell over weird smell (dry vs. vinegar), and were neutral towards acidity (dry vs. HCL).


INTRODUCTION


            What are some pill bug behaviors? Why do they do what they do?


Behavior is the way an animal acts or conducts itself: its tendencies to do something, especially towards others (Merriam Webster 2014). Behavior helps us to understand why animals do what they do. For every behavior, there is a reason or cause behind it. Two causes are proximate and ultimate causes. Proximate causes are immediate causes of an event, much of the time an instinct, and ultimate causes are the big-picture reason for why that cause, or instinct, occurs (Wikipedia 2014). For example: a zebra is drinking water, hears a loud noise, and runs away. The proximate cause of why the zebra ran away was that the zebra heard a loud noise. The ultimate cause of the zebra retreating was its survival. A proximate question about bird song would be what are some differences between bird songs? An ultimate question about bird song would be how do these differences affect the survival of birds?


            Fixed action patterns are instinctive behavioral sequences that are consistent and never change. Fixed action patterns occur in result to a stimulus. For example, a fixed action pattern of red-bellied sticklebacks is increased aggression after seeing the color red, the stimulus.


(Wikipedia 2014).

            Imprinting is the learning process of an infant that establishes a behavioral pattern (Merriam Webster 2014). For example, the first thing young geese see is their mother, so they follow her. A proximate cause for imprinting in young geese could be that the first thing young geese see after they are born will most likely be something willing to take care of them, their mother or not, and thus they follow it. An ultimate cause of this is that they will only survive if they are cared for, so they follow the thing that will most likely be willing to care for them.


            When there is a stimulus in an experiment, the result will either be kinesis or taxis. Kinesis is slow change to stimulus: movement is random and undirected. Taxis is immediate change to stimulus: movement is directed by the creature's preferences. An example of taxis would be a moth's attraction to light and an example of kinesis would be a cockroach's ambivalence to light. The moth's movement towards the light is immediate and unmistakable, while the cockroach's is random.


(Sparknotes 2014).


            There are two ways in which animals get their behavior: it can either be instinctive or learned. Classical conditioning is instinctive behavior that is automatic and involuntary. An example of this would be dogs salivating at the sight of food. Operant conditioning is learned behavior that is forced upon and voluntary. Operant focuses on strengthening or weakening behaviors through punishment or reinforcement. An example of this would be using a shock collar on a dog to stop them from barking.


(About.com 2014).


            In this lab, we will experiment with the behaviors of rollie pollies, or pill bugs, and use the above information to analyze what the pill bug behaviors are and why. We designed our experiment to determine how pill bugs respond to pH, wetness, and smell.


 

HYPOTHESIS


            If we add water, vinegar, and HCL stimuli in a 6-7 minute period, then the pill bugs will prefer the dry side of the experiment each time.                                

 

MATERIALS


            Plastic dish with paper slides, HCL, water, vinegar, 3 pipets, rollie pollies.


 

PROCEDURE

            1.         First, we set up the plastic dish and inserted two paper slides, one for each side.


            2.         Next, we placed 12 pill bugs on one of the paper slides.


            3.         Thirdly, we added water to the side where the pill bugs weren't.

            4.         We placed another plastic dish on top of the original one, and recorded data of                              how many pill bugs were on each side every minute for 6 minutes.


            5.         After the 6 minutes, we took the wet slide out and exchanged it for a dry slide.


            6.         We then dropped vinegar (after recording the acidity) into the dry side.


            7.         Repeat step 4.


            8.         Repeat step 5.


            9.         We then dropped HCL (after recording the acidity) into the dry side.


            10.       Repeat step 4.                   

The wet vs. dry experiment.

 


RESULTS

Data Tables and Graphs

Time (Mins)
Number in Dry Chamber
Number in Wet Chamber
0
12
0
0.5
10
2
1.0
10
2
1.5
11
1
2.0
11
1
2.5
11
1
3.0
12
0
3.5
12
0
4.0
12
0
4.5
12
0
5.0
12
0
5.5
12
0
6.0
11
1
6.5
11
1
7.0
11
1


           


 


 


 


 


 


 


 


 


                                                                                         

Time (Mins)
Number in Dry Chamber
Number in Vinegar Chamber
0
11
1
0.5
11
1
1.0
12
0
1.5
12
0
2.0
 
 
12
0
 
 
2.5
12
0
3.0
12
0
3.5
12
0
4.0
12
0
4.5
12
0
5.0
12
0
5.5
12
0
6.0
12
0

 

           

Time (Mins)
Number in Dry Chamber
Number in HCL Chamber
0
10
2
0.5
10
2
1.0
11
1
1.5
11
1
2.0
11
1
2.5
8
4
3.0
8
4
3.5
7
5
4.0
7
5
4.5
5
7
5.0
5
7
5.5
3
9
6.0
4
8



                               

 

 

 


 




























HCL!




CONCLUSION

            As shown in the results section, when we added a slide soaked in water, the pill bugs preferred the dry slide. At most, there were 2 pill bugs on the water side of the experiment. Both were back on the dry side in 2 minutes, while another pill bug entered the water side and stayed for a minute before the experiment ended. Upon doing some research, I began to understand why the pill bugs disliked the water. Pill bugs are land dwellers, and hydrate themselves using moisture in the air (Northern 2014). Thus, they preferred the dry slide. However, their ideal environment is a moist one, but they did not prefer the wet side because it was too wet, rather than simply humid. The experiment showed that they were not completely against the wet side, as a couple went here and there, but that just goes to show that the dry slide was the more favorable, not ideal, side.

            The pill bugs couldn’t stand the vinegar side. We placed one pill bug in that chamber in the beginning and it moved after 30 seconds. We realized that this was a matter of smell, rather than acidity, however. We found that the pH level of vinegar is 2, which is the same as HCL. Thus, we decided to test the HCL to see if the pill bugs were affected by the acidity or smell of vinegar. The pill bugs underwent a kinetic response to the HCL, unlike their taxis response to the water and vinegar. Therefore, we were able to come to the conclusion that pill bugs can smell, and we were correct. Pill bugs have tiny legs that act as sensory receptors, and allow them to smell by walking through things (Northern 2014). This confirms that pill bugs were motivated by smell rather than acidity because they didn’t mind the HCL, which doesn’t give off a weird aroma but has the same acidity as vinegar.


           



Pill bug’s legs serve as sensory receptors that allow them to smell.


(Backyard Arthropod Project 2008).


I reject my hypothesis because the results showed that the pill bugs were not always motivated by wet vs. dry, only in the first experiment when they chose the dry side over the water side. When I went into this experiment, and formed my hypothesis, I thought the lab was going to reveal one characteristic of pill bugs. Rather, it was a combination of behaviors that manifested itself in this experiment, rather than simply one. We learned that pill bugs can smell, that they use this smell to determine what environments they prefer, and that acidity doesn’t affect them (at least up until 2 pH). Further research that could be conducted to solidify the acidity results would be to try 3 more pH levels, each higher than the last. That way, we would be able to determine if high levels of acidity affect pill bugs.


The control of this experiment was the slides. Both sides of the plastic dish had slides, creating only one independent variable: the water, then the vinegar, then the HCL. The pill bugs, the dependent variable, mostly disliked the water, completely disliked the vinegar, and were nonpartisan to the HCL. 2 constants were the plastic dish over the other plastic dish (creating a shadow for the pill bugs), and the side opposite the independent variable was always dry. 2 potential sources of error were the fact that we couldn’t see the pill bugs until after each 30 second period (they could have gone back and forth without us knowing) and the independent variable leaking onto the dry side.


CITATION


            “A Field Guide to the North Side of Old Mill Hill." The Backyard Arthropod Project RSS. N.p., n.d. Web. 03 Apr. 2014.http://somethingscrawlinginmyhair.com/2008/02/16/pillbug-armadillidium/.


"Animal Behavior." SparkNotes. SparkNotes, n.d. Web. 03 Apr. 2014.http://www.sparknotes.com/biology/animalbehavior/orientationandnavigation/section1.rhtml.


"Behavior." Merriam-Webster. Merriam-Webster, n.d. Web. 03 Apr. 2014.http://www.merriam-webster.com/dictionary/behavior.


"Fixed Action Pattern." Wikipedia. Wikimedia Foundation, 04 Feb. 2014. Web. 03 Apr. 2014.http://en.wikipedia.org/wiki/Fixed_action_pattern.


"Imprinting." Merriam-Webster. Merriam-Webster, n.d. Web. 03 Apr. 2014.http://www.merriam-webster.com/dictionary/imprinting.


"Proximate and Ultimate Causation." Wikipedia. Wikimedia Foundation, 30 Mar. 2014. Web. 03 Apr. 2014.http://en.wikipedia.org/wiki/Proximate_and_ultimate_causation.


Wright, Johnathon. "Pillbugs." Pillbugs. N.p., n.d. Web. 02 Apr. 2014. http://www3.northern.edu/natsource/INVERT1/Pillbu1.htm.


 


           


 


 


 


 


 


 


 


 


 

 
 

 


 


 

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