Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
The Effects of Light and Moth Balls
On the Favoring Behaviors of Pill Bugs
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
Purpose
We did this experiment to study pill bugs preferences as to their environment. We did a control in
which each side of the behavior dish had filter paper in the bottom to determine how they normally act as
to how many are in each side at a given time. Then we continued to do three more variable tests. The
first one was to see if the pill bugs were fonder of the light or the dark. Since we know that pill bugs are
nocturnal we thought that if pill bugs were given the choice between light and dark conditions then they
would choose dark. The next variable we changed was to see if little pill bugs were fond of moth balls or
not. The third and last was to see if large pill bugs were also fond of moth balls or not. Our hypothesis
was that if both the large and small pill bugs were put in a behavior dish and given a choice between
moth balls or no mothballs then they would choose none.
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
Background Information
Pill bugs are also called wood lice, roly-poly bugs, and sowbugs. These “bugs” are not actually
insects; they are isopods. Their classification is as follows.
Kingdom
Animalia
Phylum
Arthropoda
Subphylum
Crustacea
Class
Malacostraca
Order
Isopoda
(isopods)
Some of their cousins would be lobsters, shrimp and crabs. Isopods are the only crustaceans that can
successfully live their whole lives out of water. Since they use gills to breathe they need to live in a very
humid place which is why you will usually find the pill bugs in damp soil under logs or tree roots. Pill bugs
are nocturnal. The isopods have seven jointed legs and two antennas which help the pill bugs maneuver.
The specimens also have seven segments of their body which are considered part of the thorax. The
isopod does have two eyes and four mouths. Pill bugs bred between May and September and start out
as eggs in a ventral pouch called marsupium. The eggs hatch within days of being laid. They spend a
couple of hours in the sack and then after absorbing all the fluid in the marsupium leave the mother.
They only have 6 legs to start and other then that look just like their elders, just smaller. Pill bugs will molt
anywhere from 4 to 5 times in their life times. Their diet consists of decaying plants and animals and the
occasional living plant, making them omnivores.
We observed the pill bugs in their dirt dishes and then in the behavior dishes. During this time we found
that the pill bugs were skittish for about 5 seconds during which time they would roll up in a ball. Once
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
they came unrolled some of them got stuck upside down which was entertaining to watch. Most of them
stayed in the side they were put in staying to the sides of the behavior dish until they came to the hole inbetween sides at which point they would continue on the side they were crawling instead of crawling past
the hole. After about five minutes of containment they did start to show some signs of braveness. Some
of the larger specimens would crawl across the hole or even a couple were brave enough to walk clear
across center of the behavior dish. They kept a steady pace through the majority of the test until we
shook the behavior dish at which time they seemed to pick up speed to a run and frenzy pattern. Their
social patterns were very intriguing as well. They seemed to ignore each others presence until they
needed one another. For instance they would just walk over each other if one was in his/her way. They
did pile on each other to the sides though; it was like they were trying to get out. Some did seem to fight
with each other though. They would pile on top of each other backs down and flailing around holding the
other one in their legs on top. The little pill bugs would hitch rides on the backs of the big bugs until the
big bugs noticed and then they would roll over and seem to fight with them. Over all they did not seem to
settle down just get braver. They never stopped moving.
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
Materials

Pencil

Paper

Sink with hot water

Soap

Twenty pill bugs (ten small, ten large)

Bowl full of dirt to keep the isopods when you are not experimenting with them.

Behavior dish

Black construction paper

Scissors

Light

Stopwatch

Scotch tape

Mothballs (4 grams)

Filter paper

One Coffee Filter

Electric scale
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
Procedure
Control
1) Take the behavior dish and clean it using hot water and soap.
2) Cut out filter paper to fit into the shape of each side of the behavior dish.
3) Tape all of the sides of the filter paper down to the appropriate side of the behavior dish so
that the bugs have no chance of crawling underneath the paper.
4) Collect 10 pill bugs of varying sizes out of the dirt and place five in each side of the behavior
dish.
5) Let settle for a couple of minutes keeping something in the passing lane between sides so
you still have five on each side.
6) Record amount of pill bugs on each side every minute for 10 minutes in data table labeled
control.
7) Calculate average and record in data table.
Light VS. Dark
1) Clean a behavior dish with hot water and soap.
2) Cut out filter paper to fit into the shape of each side of the behavior dish
3) Tape all of the sides of the filter paper down to the appropriate side of the behavior dish so
that the bugs have no chance of crawling underneath the paper.
4) Cut out black construction paper so it will cover only and all of side B.
5) Place behavior dish so side A will be lit by the lamp.
6) Place 5 pill bugs in each side of the behavior dish.
7) Cover side B with the precut construction paper.
8) Let the pill bugs settle for a couple of minutes and then record the amount of pill bugs on
each side every minute for ten minutes in the data table labeled Light VS. Dark.
9) Calculate average and record in data table.
Mothballs with Small Pill bugs
1) Clean a behavior dish using hot water and soap.
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
2) Cut out filter paper to fit into the shape of each side of the behavior dish.
3) Tape all of the sides of the filter paper down to the appropriate side of the behavior dish so
that the bugs have no chance of crawling underneath the paper.
4) Using the coffee filter measure exactly 4 grams of moth balls using an electric scale set to
account for the weight of the coffee filter.
5) Put the measured amount of moth balls into side B.
6) Spread out evenly being extra careful not to directly inhale the mothballs’ fumes.
7) Place 5 small pill bugs in each side.
8) Let settle for a few minutes and then record amount of pill bugs on each side every minute for
10 minutes.
9) Record results in data table labeled Mothballs Small Pill Bugs.
10) Calculate average and record in data table.
Mothballs Using Large Pill Bugs
1) Clean a behavior dish using hot water and soap.
2) Cut out filter paper to fit into the shape of each side of the behavior dish.
3) Tape all of the sides of the filter paper down to the appropriate side of the behavior dish so
the bugs have no chance of crawling underneath the paper.
4) Using the coffee filter measure exactly 4 grams of mothballs using an electric scale set to
account for the weight of the coffee filter.
5) Put the measured amount of mothballs into side B.
6) Spread out evenly being extra careful not to directly inhale the mothballs’ fumes.
7) Place 5 large pill bugs in each side of the behavior dish.
8) Let settle for a few minutes and then record amount of pill bugs on each side every minute for
10 minutes.
9) Record results in data table labeled Mothballs Large Pill Bugs.
10) Calculate average and record in data table.
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
Results
Control
Time
(in minutes)
0
Side A
(amount of pill bugs)
5
Side B
(amount of pill bugs)
5
1
7
3
2
6
4
3
6
4
4
5
5
5
6
4
6
5
5
7
5
5
8
4
6
9
5
5
10
6
4
Average
(found via mean)
5.45
4.54
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
Light VS. Dark
Time
(in minutes)
0
Side A
(amount of pill bugs)
5
Side B
(amount of pill bugs)
5
1
9
1
2
8
2
3
6
4
4
3
7
5
5
5
6
7
3
7
4
6
8
5
5
9
6
4
10
3
7
11
5
5
12
5
5
13
2
8
14
4
6
Average
(found via mean)
5.21
4.78
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
10
Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
Mothballs with Small Pill Bugs
Time
(in minutes)
0
Side A
(amount of pill bugs)
5
Side B
(amount of pill bugs)
5
1
7
3
2
4
6
3
8
2
4
6
4
5
5
5
6
7
3
7
6
4
8
7
3
9
3
7
10
4
6
Average
(found via mean)
5.18
3.9
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
Mothballs with Large Pill Bugs
Time
(in minutes)
0
Side A
(amount of pill bugs)
5
Side B
(amount of pill bugs)
5
1
4
6
2
4
6
3
4
6
4
3
7
5
4
6
6
7
3
Average
(found via mean)
4.43
5.57
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
Conclusions
Control
The pill bugs acted as expected. According to our data the isopods stayed at about the same amount of
bugs on each side of the behavior dish. I can conclude this because the data I collected shows me that
when averaged over the ten minutes there was an average of 5.45 bugs on side A and 4.54 on side B.
Both when rounded to the nearest whole number are 5. This tells me that the expected came out of our
control that they do not favor either side when it is just a clean behavior dish with filter paper in it.
Light VS. Dark
I accept my hypothesis that the pill bugs will choose dark over light when given the choice between the
two. However my data table and graph show that it is about even. I have chosen to go against this
information because we did not give the pill bugs enough time to settle down. I think they were just trying
to get out when they all ran towards the light. The last five minutes were the most accurate in my opinion
and the average from those five minutes shows that only 3.8 liked side A and 6.2 liked side B better. In
the beginning of this part of the experiment they were running around really fast and climbing on each
other as if they were trying to get out. By the end they were all going over to the dark side and those that
were there we still and calm. This leads me to believe they liked the dark side better. In the future I
would suggest to people to let them settle more before recording results.
Mothballs with Small Pill Bugs
I accept my hypothesis for the small pill bugs. If you give a small pill bug the choice between being in
moth balls or not they will tend to prefer not. My graph and data table back up my conclusions. The
average number of pill bugs on each side tells me they prefer side A, the side with no mothballs. At the
end of this trial the average was 5.18 on side A to 3.9 on side B. Watching the pill bugs move through the
moth balls was a very sad sight. They struggled to get through the texture of it with their small legs. In
the future I would put less moth balls so they could move easier and possibly give us better numbers to
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Rachel Hannum
Class: Honors Biology
Teacher: Mrs. Cassidy
Period: 3
Date: February 2, 2009
work with. I think this is helpful in real life because if you are having a pill bug problem you could possibly
put out some moth balls and it would help to contain the problem.
Mothballs with Large Pill Bugs
I reject my hypothesis. When the pill bugs were given the choice between the side with mothballs and the
side without they did not prefer one side more then the other. My graph and data table show me that the
average was 4.43 on side A and 5.57 on side B. This shows me that there were more on side B. The
numbers for this trial are in short supply though; we ran out of time and could only conduct 6 minutes of
the trial. I think with more time we would have seen even closer numbers. I think the large pill bugs could
care less about the moth balls; they just crawled over them like they were not even there. Some of them
even used the large crystals to try and escape the behavior dish. In the future I would take 15 minutes in
order to get better numbers and there for be able to make more accurate conclusions.
Over All Conclusions
The total experiment was a joy. I liked working with the pill bugs and experimenting. They were
interesting to watch and cheer on. However, I would have liked to have more time to complete more trials
and possibly get better data from it. I think this was an overall success and would suggest it to other
students.
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