Isopod Behavior
Introduction:
Isopods classified are under phylum arthoropoda. They are crustaceans and require wet environments to breathe because they have gills. Hence they are often found underneath stones, logs, leaf litter and other debris in cool damp environments. They have three body parts including head, thorax, and abdomen and have seven pairs of legs and seven separate segments on thorax.
Question:
Do isopods prefer wet or dry environments in general?
Hypothesis:
If isopods require wet environments to breathe and respire, then they will prefer the wet environment and go to and stay in the wet Petri dish.
Materials:
•Isopods (10)
•A special Petri dish that has two dishes connected in the middle with a tunnel
•Paper (to put over the Petri dish bottom)
•Dropper
•Stopwatch
Procedure:
1.The apparatus was set up. The paper was put in both sides of the joint double Petri dish and one side was made damp by adding water with the dropper while the other was left dry.
2.The isopods were gathered and five active ones were placed on opposing extrenes of the joint double Petri dish. There were five on the dry side and five on the wet side.
3.The isopods were observed in time intervals of three minutes. Data regarding movement from one Petri dish to another was recorded.
Data:
Number of pillbugs in dried Petri dish (start with 5)Number of pillbugs in wet Petridish (start with 5)
3 minutes later 6 4
6 minutes later 5 5
9 minutes later 3 7
12 minutes later 5 5
15 minutes later 3 7
18 minutes later 1 9
21 minutes later 0 10
Conclusion:
This experiment served to determine which kind of environment isopods prefer-wet or not wet. It was found that isopods preferred the wet environment over dry environments. Over the 21 minute interval in which we observed the isopods, isopods moved from dish to dish randomly at first when exposed to their new environment. Some isopods left the wet environment to go to the dry environment. This random movement can be explained by behavioral biology. Such undirected movement is kinesis and results when exposed to a new environment. However, after being exposed to their new environment for a while, the isopods started moving in response to the stimuli in place. They started moving toward the wet environment and staying there. This directed movement is taxis. The isopods prefer the wet environment because isopods have gills and wet environments allow them to respire more efficiently. Our hypothesis was also proven correct by our data and analysis.
