Basham 1
Substrate and moisture preferences of terrestrial
isopods.
C. Brett Basham,
Conservational Biology, Tennessee Tech University, Cookeville, TN 38501.
February 27, 2006
Table of Contents: Project Summary (p.1)
Introduction (p.1)
Methods and Materials (p. 2)
Expected Results (p.2)
Data form (p. 3)
Timeline (p.4)
Budget (p. 4)
Literature Cited (p.4)
Project Summary: Terrestrial isopods, like their aquatic relatives use tracheae like
gills to breath. I hypothesize that in order for them to breathe properly they must be able
to respond to changes in moisture levels in their environment due to abiotic factors. I will
test this hypothesis with a set of experiments that will test both the isopods’ responses to
different moisture levels and their response to different substrates. I expect to find that
the isopods will have a definite preference for both moisture levels and substrates that
match that of their natural environment.
Key Words: terrestrial isopods, substrate, abiotic factors,
Domain: Eukarya
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Isopoda
Family: Armadillidiiae
Species: Armadillidium vulgare
Introduction: Isopods are found in dark, damp places. Terrestrial isopods are the only
crustaceans that have totally abandoned an aquatic environment for a terrestrial one.
(Brusca 1985) Isopods break down organic material, especially leaf matter and greatly
aids in the production of humus. (Rapp 2001) Young isopods emerge in the spring and
walk from a few to over one thousand meters before establishing burrows of their own.
(Baker 2005) Fossil evidence even shows that isopods occurred in the Late Jurassic and
inhabited coastal mudflats. (Gaillard et al. 2005) Isopods are able to perceive the
presence of toxic compounds and are able to escape from contaminated to clean soil.
(Loureiro et al. 2005)
Basham 2
Methods and Materials: There will be two separate experiments. The first
experiment will test how the isopods respond to different moisture levels on a simple,
artificial substrate. This will be done by placing two halves of filter paper with different
moisture levels in a Petri dish and counting the number of isopods on each side after a
time. The second will test how they respond to the preferred moisture level of the first
experiment on different natural substrates. This will be done by placing two different
substrates in a Petri dish and counting the number of isopods on each side after a certain
time period. I will analyze the data from each experiment using the G-test, and then by
using a chi squared table to determine if my findings are significant.
Materials:
- Petri dishes
- filter paper
- dark soil
- red clay
- sand
- water
Expected Results:
OBSERVATION
Isopods live in dark, damp areas and must have moisture to survive.
PROBLEM
Will isopods show a preference to different moisture levels and certain substrates?
HYPOTHESIS
Yes, isopods will show preference to moisture levels and substrates that resemble their
nature environment.
NULL HYPOTHESIS
The isopods will show no preference for moisture levels or substrate.
EXPERIMENT/METHODS
The independent variable in my experiment is different moisture levels. The dependant
variable in the experiment is the isopods. The controlled variable is dry substrate.
ANTICIPATED RESULTS
I predict my hypothesis will be correct and that the isopods will be able to react to
moisture levels and show a preference.
Expected Results and Experiments: For both experiments the isopods will show
a preference. For the first experiment I predict they will prefer the moist substrate. For
the second experiment I predict that they will have a preference for the dark soil.
Basham 3
Data form:
Substrate and moisture preferences of terrestrial
isopods.
Location: __________________________________________________
(Facility name)
(City)
(County)
(State)
Sample Taken by:
___________________________________________________________
(Name)
(Position)
(Organization)
Preferred
Rejected
Showed No
Preference
Dry
Moist
Drenched
Dark soil
Red clay
Sand
Remarks:
______________________________________________________
______________________________________________________
Signature: _________________________
Date:__________
Basham 4
Time line:
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Po
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C
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18
16
14
12
10
8
6
4
2
0
yp
Weeks
Timeline
Budget:
Salary- $500
Nonexpendable-$100
Expendable-$150
Indirect Costs-$75
Travel-$175
Literature Cited:
Baker, M. 2005. Experience influences settling behaviour in desert isopods, Hemilepistus
reaumuri. Animal Behavior 69: 1131-1138
Brusca, R. 1985. The biology of terrestrial isopods. Science 230: 659
Gaillard, C., P. Hantzpergue, J. Vannier, A. Margerard, J. Mazin. 2005. Isopod trackways
from the Crayssac Lagerstatte, Upper Jurassic, France. Palaeontology 48: 947-962
Loureiro, S., A. Soares, A. Nogueira. 2005. Terrestrial avoidance behavior tests as
screening tool to assess soil contamination. Environmental Pollution 138: 121-131
Rapp, W. 2001.The terrestrial isopods of Nebraska. Transactions of the Nebraska
Academy of Sciences 27: 9