Pillbugs’ Reaction to Different
Environments
Abstract
During the animal behavior lab,
pillbugs’ orientation behaviors towards humidity, temperature and smell were
tested. One can conclude according to the results that, during the lab, the
pillbugs preferred dry environment with lower temperature and no smell.
Introduction
The study of animal behavior is
called Ethology. It studies an animal’s response to sensory input. In the study
of animal behavior, one can study proximate questions or ultimate questions. A
proximate question focuses on the environmental stimuli that trigger the
behavior. For example, how does a bird know when to sing? An ultimate question
addresses the evolutionary significance of a behavior. For instance, why does a
bird sing (Emilyleck)? Before the lab, there are a few terms need to be
clarified. A fixed action pattern is an instinctive behavioral sequence that is
indivisible and runs to completion (Campbell). For example, a Graylag Goose will
roll a displaced egg near its nest back to the others with its beak. The sight
of the displaced egg triggers this behavior. If the egg is taken away, the
animal continues with the behavior, pulling its head back as if an imaginary
egg is still being maneuvered by the underside of its beak (Rogers). Imprinting
is a process whereby a young animal follows the characteristics of his/her
mother after hatching. It can be filial imprinting or
following a future mating partner. For example, a young goose would follow its
mother after hatching. The proximate cause may be it is hungry and need to
follow its mother to find food. The ultimate cause is that all geese follow
their mother after hatching because of evolutionary reasons (Biology Online).
There are two types of learning: classical conditioning and operant
conditioning. Classical condition occurs when a stimulus is associated with a
particular response. For example, if a dog hears a bell before receiving its
food all the time, then the dog will associate the bell with the arrival food.
Operant conditioning is a learning process that involves shaping behaviors by
using reinforcement or punishment. For example, a child will continue to eat
his vegetables if it is reinforced with a treat afterwards (Brewer). Animal behavior
falls into three basic categories: orientation behaviors, agonistic behaviors
and mating behaviors. The purpose of this lab is to study pillbugs’ orientation
behaviors. Orientation behaviors place the animal in its most favorable
environment. There are two types of orientation behaviors – taxis and kinesis.
In taxis, the animal intentionally moves towards or away from a stimulus, which
can be humidity, smell temperature, etc. For example, a pillbug move to a place
with higher humidity because it prefers humid environment. In kinesis, the
animal moves randomly without reacting to a stimulus. For instance, a pillbug
moves randomly between a humid environment and a dry environment.
Hypothesis
If a humid and a dry environment are
provided for pillbugs, they will move to the humid environment. If an
environment with strong smell and an environment without smell are provided for
pillbugs, they will prefer the environment without smell. If an environment of
lower temperature and an environment of higher temperature are provided,
pillbugs prefer lower temperature.
Materials
10
pillbugs
Box
with two chambers
Filter
paper
Water
Ammonia
Ice
pack
Stopwatch
Procedure
1. Place a piece of filter paper in one of
the chambers in the box and soak it with water. Place 10 pillbugs in the dry
chamber and cover the box. Observe the pillbugs every 30s and count the numbers
of pillbugs in each chamber for 7min.
2.
Clean the chambers. Place a piece of filter
paper in each chamber. Soak one side with water and the other side with
ammonia. Place 10 pillbugs in the chamber soaked by water and cover the box.
Observe the pillbugs every 30s and count the numbers of pillbugs in each
chamber for 6min.
3. Clean the chambers. Place ice pack under
one chamber and place 10 pillbugs in the chamber without ice pack. Observe the
pillbugs every 30s and count the numbers of pillbugs in each chamber for 6min.
Results
Time/Mins
|
Number
in Dry Chamber
|
Number
in Wet Chamber
|
0
|
10
|
1
|
0.5
|
8
|
2
|
1.0
|
8
|
2
|
1.5
|
8
|
2
|
2.0
|
9
|
1
|
2.5
|
9
|
1
|
3.0
|
9
|
1
|
3.5
|
9
|
1
|
4.0
|
9
|
1
|
4.5
|
9
|
1
|
5.0
|
9
|
1
|
5.5
|
9
|
1
|
6.0
|
9
|
1
|
6.5
|
9
|
1
|
7.0
|
9
|
1
|
Time/Mins
|
Number
in Ammonia Chamber
|
Number
in Water Chamber
|
0
|
0
|
10
|
0.5
|
0
|
10
|
1.0
|
0
|
10
|
1.5
|
0
|
10
|
2.0
|
1
|
9
|
2.5
|
1
|
9
|
3.0
|
0
|
10
|
3.5
|
1
|
9
|
4.0
|
1
|
9
|
4.5
|
1
|
9
|
5.0
|
2
|
8
|
5.5
|
2
|
8
|
6.0
|
3
|
7
|
Time/Mins
|
Number
in Room Temperature Chamber
|
Number
in Cooler Temperature
|
0
|
7
|
3
|
0.5
|
5
|
5
|
1.0
|
4
|
6
|
1.5
|
3
|
7
|
2.0
|
3
|
7
|
2.5
|
2
|
8
|
3.0
|
2
|
8
|
3.5
|
2
|
8
|
4.0
|
2
|
8
|
4.5
|
1
|
9
|
5.0
|
2
|
8
|
5.5
|
2
|
8
|
6.0
|
3
|
7
|
Conclusion
Throughout the experiments, factors
like humidity, temperature and smell are independent variables. The number of
bugs is a dependent variable. In the first lab, temperature and brightness are
constants when humidity is changing. During the experiment, there were always
more bugs in the dry chamber. As a result, it proves that the more humid the
environments is, the less the pillbugs like it, and it failed to prove my
hypothesis of pillbugs like humid environment. In the second lab, temperature,
brightness and humidity are constants while one chamber smells (because of
ammonia) and the other does not. There were more bugs in the chamber that does
not smell throughout the entire experiment. Thus, it proves my hypothesis. In
the third lab, brightness and humidity are constants while temperature changed.
There were more bugs in the chamber with lower temperature throughout the whole
experiment. Therefore, it proves my hypothesis that pillbugs prefer lower
temperature. Two potential errors in this lab can be: First, seven and six
minutes were not enough time for the pillbugs to react to its surroundings, so
the pillbugs did not have enough time to move to the chamber they prefer. Secondly,
after the second lab, the smell of ammonia might not have been completely
cleaned up. As a result, the pillbugs can still smell ammonia and stayed in one
chamber for that reason
Work Cited List
Biology
Online. “Imprinting.” Web.
Brewer. “Classical and
Operant Conditioning.” University of Massachusetts Amherst, 2011. Web.
Campbell, N. A. Biology (4th edition), Chapter 50. New
York: Benjamin Cummings, 1996. Web.
Emilyleck,
“Chapter 51: Study Questions ~ Behavioral Ecology.” Quizlet.com. Web.
Rogers,
Philip. “Fixed Action Pattern” video. Sep. 14th, 2009. Web.
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