Pill Bugs Prefer Moisture Content of Water over Soda - Lab Report Example

Biology 20 April Pill Bugs Prefer Moisture Content of Water over Soda Pill bugs are members of phylum Arthropoda and are closely related to crustaceans like shrimps, lobsters etc. These species breathe with the help of gills and thus they require high moisture content for survival. This experiment is based on the ethology of pill bugs. Mainly two hypotheses were stated in this experiment and the two hypotheses are pill bugs prefer moist condition over dry condition and pill bugs prefer environment moist with water over soda. Experiments were conducted and on the basis of the observations the hypothesis that pill bugs preferred water moist environment was proved to be true, thus the null hypothesis were rejected. So according to the results obtained, it can be concluded that pill bugs are better suited to environment moist with water as they require high moisture provided by water for their survival. Introduction: Pill bugs are the common crustacea belonging to the order isopoda and are “closely related” to lobsters, shrimps as well as crabs (Schofield ). They have oval or slightly elongated structure with seven pairs of legs and their colour ranges from dark grey to white. Pill bugs are also called “rolly-pollies” as they roll into tight ball as soon as they sense danger (Koehler 1999). This action of “conglobation” protects them from predators and also safeguards the delicate ventral surface of the organism and helps them to survive under lethal conditions (Smigel & Gibbs 2008). The water loss is very high in terrestrial isopods, thus the process of conglobation help in conserving water in the case of pill bugs as they are the only crustacea that can perform conglobation. (Smigel & Gibbs 2008). Pill bugs are usually seen under “natural debris” like rocks, logs and also under bricks, boards, trash, decaying vegetation or areas where the humidity is high (Holland par. 2014). They are omnivores and feed primarily on decaying organic matter and also damage the roots of green plants. Pill bugs are crawling, that is slow moving arthropod and require high moisture content and are usually active during night. Pill bugs obtain oxygen with the help of “gills” located underside of the body and since it is a type of terrestrial species, its gills require continuous wetting for its functioning and hence pill bugs are mostly seen in moist areas (Colorado Crustacean of Interest: Pillbug(“Roly-Poly”) 2013). The main issue seen with the pill bugs are drying out in the terrestrial environment. Pill bugs have the ability to absorb the water vapour from the damp air probably with the help of its gills. In this experiment, the behaviour of the organism was observed including their speed, appearance and preferred direction of motion. In the first experiment, observations were made to prove the hypothesis that pill bugs prefer moist condition than dry condition. According to the nature of the organism, they prefer moist environment for the functioning of their gills through which they respire. There are different moist environment and the second experiment was conducted to prove the second hypothesis that pill bugs preferred environment moist with water over soda. For this test, two moist medium were used, water and soda (pepsi cherry), and results were drawn on the basis of observation. For every experiment there may be a few hypothesis and null hypothesis based on the observation. In this case the hypothesis is that the pill bugs will prefer moist environment with water over soda and the null hypothesis is that the pill bug does not prefer moist environment with water over soda. Methods and Materials: Firstly the direction of motion of the pill bugs was observed. 4 pill bugs were introduced into a graduated cylinder one by one and experiment was conducted with the angle of the cylinder and the direction of motion of the 4 pill bugs was noted. 4 pill bugs were observed and metric rulers and a stopwatch were used to measure the time taken by the organism to cover a certain number of millimetres and the result was recorded. The patterns of movement of the species were observed inside the petriplates. In the first experiment, test is based on the hypothesis that pill bugs prefer moist environment than dry environment. Two petriplates were taken and they were connected with each other so that the bugs can travel between the two plates. A piece of filter paper was placed on each petriplate and one piece of filter paper was wet with water. 4 pill bugs were placed in each dish and after a wait of 5 minutes, the bugs were observed on the basis of how well they acclimate to their new surroundings. In the next 10 minutes, the number of organisms present in each habitat was noted during every minute. The mean of the observation was calculated and checked whether the data obtained supports the hypothesis. The next experiment is based on the hypothesis that pill bugs prefer environment moist with water over soda. In this experiment two petriplates were used and these petriplates allowed for the movement of pill bugs between the two plates. A piece of filter paper was placed in each dish and one side was filled with water and the other side was filled with soda (pepsi cherry). 4 pill bugs were introduced into each plate and after 5 minutes, it was seen how the organism adjusted to the new environment. The observation showed that the number of pill bugs in each dish was counted by stopping after every 60 seconds using a stopwatch. The number of pill bugs in each plate was noted and the mean was calculated. The same procedure was repeated two more times for best result. Result: Based on the observation made on the direction of motion and the speed calculated, it is clear that pill bugs move quickly and within a graduated cylinder all the 4 pill bugs tried to move in the upward direction. They are small in size but the average speed of the 4 pillbugs observed was 7.99mm/sec. The pill bugs tended to crowd around each other within the petriplates. According to the data tabulated in the first experiment regarding the preference of pill bugs for moist environment; the mean values calculated were 6.3 and 1.7 for moist environment and dry environment respectively. From the mean value it is clear that pill bugs prefer to live in moist environment than the dry condition. According to the observations made in the 3 sets of experiments based on the hypothesis that pill bugs prefer moist environment with water over soda (pepsi cherry) the mean value obtained in the first set of experiment were 5 and 3 for water and soda respectively. Hence it is clear that pill bugs were more adapted to environment moist with water rather than soda. In the second set of experiment, the mean values were estimated to be 4.8 and 3.2 for water and soda respectively. In this experiment also more number of organisms stayed in water environment as compared with the soda. In the third experiment, the mean values were 5 and 3 for water and soda respectively and thus the hypothesis stated is true that pill bugs prefer water environment over soda. Graph showing the 3 sets of experiment done on the hypothesis that pill bugs prefer environment moist with water over soda: On the basis of three sets of experiment conducted on the basis of hypothesis that pill bugs prefer environment moist with water over soda, it is clearly understood that more number of pill bugs were seen in environment moist with water than soda. Discussion: Many experiments have been conducted in order to study and understand the ethology of pill bugs. The mean values of the data collected were then calculated thus validating that the hypothesis was true. It was observed that organism was more adapted to moist condition than dry condition within the given time. Three sets of experiments were conducted for the second hypothesis and the count was tabulated. In the three experiments performed, the mean of each experiment was calculated and the result was studied. According to the calculation, in the three experiments, the number of pill bugs adapted to environment moist with water was more than that of soda. Hence the null hypothesis that the pill bugs do not prefer water environment over soda was rejected. Pill bugs rely on constant form of moisture as they lack waterproofing cuticle waxes and are easily susceptible to drying out and thus they prefer wet environment. Under high humidity, pill bugs absorb the water vapour for rehydration. Pill bugs respire through gills and thus they require water for its survival. Soda like pepsi is carbonated drink which contains carbon dioxide gas in dissolved state and is slightly acidic in nature. The pill bugs seemed to be more comfortable in water and thus they preferred environment moist with water over soda. Studies on effect of soda on pill bugs haven’t being studied much, however as pill bugs are easily available, experiments are being conducted to find more favourable media to suit the organism. Works Cited Colorado Crustacean of Interest: Pillbug (“Roly-Poly”). n.d. Web. 20 April 2014. Holland, Asa. Armadillidium Vulgare Pillbug. Animal Diversity Web. 2012. Web. 20 April 2014. < http://animaldiversity.ummz.umich.edu/accounts/Armadillidium_vulgare/> Koehler, P. G. Pillbugs, Centipedes, Millipedes and Earwigs. University of Florida. EXTENSION: Institute of Food and Agricultural Sciences. n.d. Web. 20 April 2014. Powell, Peggy K. Sowbugs & Pillbugs. West Virginia University: Extension Service. 1914. Web. 20 April 2014. Schofield, Kimberly. Pesky Pill Bugs. Texas Cooperative Extension: The Texas A & M University System. n.d. Web. 20 April 2014. Smigel, Jacob T. & Gibbs, Allen G. Conglobation in the Pill Bug, Armadillidium Vulgare, as a Water Conservation Mechanism. Journal of Insect Science. Vol. 8. n.d. Web. 20 April 2014. < http://www.insectscience.org/8.44/i1536-2442-8-44.pdf> Smigel, Jacob T. & Gibbs, Allen G. Conglobation in the Pill Bug, Armadillidium Vulgare, as a Water Conservation Mechanism. Journal of Insect Science. University of Wisconsin Library. 2008. Web. 20 April 2014. Read More