The Effects of Moisture and Light on Isopod Behavior

The study of animal behavior is called Ethology. Responding to sensory input is what animal behavior essentially is. Animal behavior falls down to three categories: orientation, agonistic, and mating. Orientation behavior involves the animal proceeding to its most desired environment that best suits it. When an animal travels towards or away from a stimulus this is defined as Taxis. Taxis occurs when a stimulus is altered for example the change in heat or light. When an animal interacts with each other in hostile or compliant movements this is called Agonistic behavior. Finally, mating behavior occurs essentially when a member of the same species finds another member and mate. Terrestrial isopods are also known as Pill Bugs. They are crustaceans that dwell on land. They are related to lobsters, crab, and shrimp. Pill bug growth involves the molting of an exoskeleton while shedding their cuticles in waves. Pillbug have a diet consisting mainly of decomposed vegetables, grass, weeds, fruits, and plants. Pillbugs are located in moist environments, specifically under logs or leaves for example.

As the experiment progressed there was something worth pointing out. First off, the pillbugs experienced kinesis and taxis as they moved towards a dark moist environment. This stimulus is what is causing the animal behavior to occur. As noted at 6:45 PM, in the experiment, the pillbugs were still continuing to move however they appeared to be hesitant since they weren’t familiar with the area, especially the dishes with bright light (taxis). Some of the pillbugs weren’t affectionate towards the light as they moved to areas with shade or all the way back to the dark petri-dishes. Agonistic behavior was not observed during the experiment since the pill-bugs were relatively friendly and not hostile. In fact, the pillbugs were actually passive and the only time they touched each other was during mating. Signs of mating behavior was seen only once during the whole experiment. In some cases the larger pill bugs were seen to be on top of smaller ones while moving which might suggest that communication was indeed being taken place at times. This form of behavior does not help the pillbug defend against natural predators however the natural defense mechanism does. When a pillbug senses danger it curls up into a ball as observed when they were picked up. Pill bugs are really small so they cannot be seen by many.

Pill bugs are great at hiding due to their ability to bury themselves along with their color schemes. One way I could have better improved this experiment was to place no bedding material in the middle petri dish so that the pillbugs could possibly have had an easier chance of going to other petri dishes. Errors that might have been present in the experiment could have been due to such a small testing size. This could have been improved by adding more pillbugs because the higher the sample size the more likely the data will be more accurate.

Based off the experiment results, pill bugs prefer dark environments over lighter ones. Pill bugs also prefer wet conditions over dry conditions. The petri dish with dark wet conditions proved to be the most suitable for the pillbugs since their was the most activity coming from that dish alone. In conclusion, Pill bugs prefer dry and wet environments the most.