Pill Bug Lab Essay Example

that the pillbugs liked dark, damp, sheltered and hot spaces as oppose to light, dry, open and cold areas. This was concluded because, as shown in Tables/Figures 1, 2, 3, 4; the bugs seemed to congregate in the dark, damp, sheltered and hot chambers mostly.However, for a few minutes in each of the experiment, the bugs did not respond in the way we had hypothesized.

This could be due to the fact that these animals have been used for prior experiments for weeks and weeks. These animals are obviously aggravated from these experiences; therefore they might not have wanted to go through it all again and did not want to cooperate with us as a whole. My hypothesis is that these animals will prefer the cold, sheltered, dark and damp habitats as opposed to hot, open, light and dry environments.

INTRODUCTION

There are many different ways to classify animal behavior and behavioral types. Behavior in terms of an animal’s response is a result of sensory input and falls within the categories of innate (inherited) and learned behaviors. When an animal is in a favorable environment it is called orientation behavior (Laboratory Manual 137).

When an animal moves either toward or away from heat, light, or moisture, it’s called taxis. When an animal’s movement is completely random, it is called kinesis. The way an organism moves can be either taxis or kinesis. Another kind of behavior is how organisms behave when mating.Part of the mating ritual involves agnostic behavior where animals respond to each other with aggressive or submissive behaviors. Behavior with other organisms includes appearances, movements, and interactions with each other.

Terrestrial isopods are land dwelling crustaceans, commonly known as

sowbugs or pill bugs (or roly-pollies). While they look similar, sow bugs are different from pill bugs. An Animal’s behavior is often erratic and hard to study. However, in a controlled environment, it is easily done. We used Pillbugs in this lab, and placed them in various conditions.

We tested to see if they would prefer a damp over dry environment, a hot over cold, a dark versus light and an open environment over a sheltered one. A natural defense mechanism for the Pillbugs is to curl themselves up into a tight ball and basically, play dead. When set in various conditions they can perform orientation behaviors. These behaviors include taxis and kinesis. Taxis occur when the animal moves towards or away from a certain stimulus. Kinesis occurs when the animal moves in a random motion in response to the stimulus.

Throughout this lab, we put the pillbugs through four different tests.These experiments are to test to see if these animals will prefer a certain habitat rather than another and how they show this is through either kinesis movement or taxis movement.

MATERIALS AND METHODS

In all labs, a lab book and a pen or pencil are essential to record the number of pillbugs. The times come up fast so you have to make sure you are watching the clock or stop watch. Obviously, do not poke the pillbugs or try and force them into a certain chamber aggressively, this will aggravate them and cause unreliable results.

When you are trying to get your pillbugs, use a paintbrush to sweep them onto your brush and then carefully lace them into the choice chamber dish that is provided for you. Make

sure to get 10 pillbugs so you can have five in each chamber. If they look dead, they are most likely just curled up. During the various tests, make sure to take notes on the appearance, the types of movements (kinesis or taxis) and the interactions between the animals.

The first experiment is to find out if the pillbugs prefer dark or light environments. The choice chambers have a little passageway between the chambers. Make sure to gently place five pillbugs on each side and then block off that doorway with a cardboard barrier of some sorts.Pick one of the chambers and then cover that chamber with something that will make the chamber be a dark environment.

Leave the other chamber completely untouched, this will be the control group for the experiment. Obtain a stop watch and remove the barrier. Then record the amount of pillbugs on the light and dark chambers after every 30 seconds. We recorded our results every 30 seconds for 10 minutes. After the 10 minutes are over, take the cover off the dark chamber and make sure you have all 10 pillbugs still and then place the clear chamber covers to ensure that the bugs won’t escape whilst you get the second experiment ready.

Remember to document in your lab book which is the independent and dependent variable for each of your experiments, this will make it easier to graph them later on. The next test is to see if the animals find a damp environment more appealing than a dry one. This is done by damping a white circular disk of paper with water and placing it in one of the chambers.

When doing this, make sure that all 10 pillbugs are on one side so you will not be placing the damp paper on top of a pillbug. Just like the previous experiment, place five pillbugs on each side of the chamber and block the doorway.

When the timer is ready, open up the entry way and time for 10 minutes, recording the number of pillbugs on each side every 30 seconds. When the 10 minutes has elapsed, carefully rally the pillbugs to the dry chamber and remove the damp paper and cover the chambers with the clear cover again. For the third experiment we tested if the pillbugs would prefer a sheltered environment as oppose to an open one. This is done by placing a cardboard shelter in one of the chambers. The shelter should fit in the chamber and should not cover the whole chamber (if it did, then the experiment would be like the first test conducted).This time, when recording the number of bugs, you will have to count the number of bugs out in the open (even if they are in the chamber with the shelter, if they are not under the shelter than they are in the open).

Again, you will keep time for 10 minutes, recording your data every 30 seconds. After the 10 minutes is up, remove the shelter and make sure that all 10 pillbugs are still in the chambers. The final experiment is testing the temperature preference of the pillbugs. First, obtain two Petri dishes; fill up one of the Petri dishes with ice from the freezer and the other with hot water from the hot water bath.

Then place

the chambers on top of the Petri dishes, making sure that the hot water was underneath one chamber and the ice was underneath the other. Remove the barrier between the chambers and record your results every 30 seconds for 10 minutes. After the ten minutes are over, throw out the hot water and ice and place your Petri dishes back. Return the 10 pillbugs to their makeshift habitats carefully and then clean up your area and materials.

RESULTS

For the first experiment, we tested to see if the Pillbugs preferred darker condition to lighter ones.The animals would swarm to each other initially, but after a few seconds they began to spread out. As seen in Table 1 and Figure 1, the animals preferred the dark side. When a Pillbug would come out from the dark chamber, it quickly went back, usually taking another Pillbug with it. There were a few who hung out in the doorway between the two chambers; we counted that as being on the dark side because it was slightly covered.

The second experiment was to test the Pillbug’s response to damp versus dry conditions. After setting up the test we learned that most of the Pillbugs enjoyed being on the damper chamber as oppose to the dry chamber.As you can see by the observations on Table 2 and Figure 2, one particular Pillbug enjoyed the damp area so much that it sprinted to that side and ran in circles. The next experiment we did was to test the pillbug’s response to a shelter.

The shelter is different than the dark and light test because only a part of the chamber is covered, not the whole

thing. As seen by Table 3 and Figure 3, the Pillbugs liked the shelter more so than being out in the open. For the majority of the time, the number of Pillbugs was even on each side but there were more bugs underneath the shelter than out in the open.The final experiment we conducted was to test the animal’s response to hot and cold conditions.

The number of Pillbugs seemed to stay fairly consistent throughout the 10 minute period as seen in Table 4 and Figure 4. However, for the most part, the Pillbugs were on the hot chamber more than the cold chamber until the very end. For the last minute the Pillbugs scooted over to the cold chamber. Observations of Pill bugs Behavior in Response to Light Time (Min)Number of Pillbugs in “Light” ChamberNumber of Pillbugs in “Dark” ChamberOther Notes and Observations 055Some of the pill bugs were fighting with one another.555 155 1.

564One of the pill bugs went to the light side. 255The bug didn’t like the light and went back to the dark side. 2. 555 355 3. 555Pill bugs are on top of each other. 455 4.

555 564 5. 573 682 6. 564 755 7. 546 864 8. 564 955Very clustered.

9. 564 1082 Table 1 Number of Pillbugs in Each Light or Dark Chamber depending on the Time (in minutes) Figure 1 Observations of Pill bug Behavior in Response to Dry & Wet Conditions Time (Min)Pill bugs in Dry AreaPill bugs in Wet AreaOther Notes and Observations 055 .564 155Several Pill bugs ran into the wet side and ran around the area in a circular formation. . 564 237 2.

519Taxis movement

away from the dry area.319 3. 5010 4010Clustered again in wet area. 4. 528 537 5. 537 628One of the pill bugs was pushed into the wet area by another pill bug.

6. 528 719 7. 5010 8010 8. 5010 9010 9. 5010 1028 Table 2 Number of Pillbugs in Each Wet and Dry Chamber depending on the Time (in minutes) Figure 2 Observations of Pillbug Behavior in Response to Shelter Time (Min)Number of Pillbugs in ShelterNumber of Pillbugs not in the ShelterOther Notes and Observations 055 .555 155Not under the shelter but around it 1.

564 273 2. 573 337 3. 573 482 4. 591 582 5.

573Some are fighting 73 6. 555 755 7. 555 855Are either moving or stationary 8. 564 982 9. 573 1055 Table 3 Number of Pillbugs Under and Out of the Shelter depending on the Time (in minutes) Figure 3 Observations of Pillbug Behavior in Response to Hot & Cold Conditions Time (Min)Pill bugs in the Hot areaPill bugs in the Cold areaOther Notes and Observations 055 .

546 164 1. 564 255 2. 555 364Taxis movement of two bugs to the hot area. 3. 564 464 4.

555 546 5. 556 646 6. 555 746Several Pill bugs cannot decide on which area to go to. 7. 546 855 8. 555 928Kinesis movement away from the hot area.

9. 528 1028 Table 4.Number of Pillbugs In the Hot and Cold Chambers depending on the Time (in minutes) Figure 4.

DISCUSSION

When the group was gathering our Pillbugs from their makeshift habitat, I noticed that the majority of them were attached to the underneath of a piece of paper towel.

I speculated that they preferred darker scenarios and

my results seemed to support this speculation. From this information I also suspected that the animals would prefer the shelter rather than an open area. Especially since they had a defense mechanism of curling into a ball, I figured that the Pillbugs did not like to be open and vulnerable to predators.Also, they are usually found in dirt environments, which means that they would prefer moist areas as oppose to dry ones. Some of the experiments were inconsistent with the movement of the Pillbugs. In the beginning of each experiment, the pillbugs seemed to show taxis movement, as in they were moving away from the stimulus that displeased them and moved towards the one that they preferred.

However, as the test went on, especially in the fourth test (as seen in Table 4 and Figure 4), the pillbugs performed movements closer to the kinesis definition.This was totally unexpected, especially since the bugs were supporting out hypothesis in the beginning. This change in attitude could be because of numerous things. The experiment was not conducted properly, the hot water was not hot enough, the cover did not cover the whole chamber, or these pillbugs have been poked and prodded for a long time now. Therefore, they might have been exhausted and fed up and did not want to cooperate with us.

LITERATURE CITED

1. Wagner, David, Theodore Taigen, Thomas Terry, and Karen Lombard. Biology 102: Foundations of Biology. Fall 2006 Stamford Edition. 129-137.
2. Unknown: University of Connecticut, 2007.