House Cricket Experiment Essay

1227 Words Mar 26th, 2014 5 Pages
House Cricket Experiment

Introduction The topic of house cricket aggression in response to residency has been previously studied. (Alexander 1961) split this aggression behavior into five levels: 1) no aggression, dominance, or retreat; 2) no aggression with a retreat by one cricket; 3) mild one-sided aggression with mild repercussion; 4) moderate to intense aggression from both crickets; or 5) sustained combat. Interestingly, in Polistes wasps (Pardi 1948a), Sphecius wasps (Mr Norman Lin, personal communication), and crayfish (Bovbjerg 1953; Lowe 1956) aggressive behavior has been split into four or five levels. (Alexander 1961)
The experimental organism in this experiment was Acheta domesticus, more commonly known as the house
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The containers were plastic and 18 by 15 by 6 centimeters long. Prior to the experiment being performed, the crickets had spent a week in these residencies. Along with the crickets in the plastic containers, there was wet pieces of paper towel and a slice of carrot. The procedure started with placing the intruder cricket into another cricket’s residence. The intruder was distinguished from the resident by marking its body with a colored marker provided for the experiment. Once the intruder was in the container, a trial of ten minutes started. The object was to tally the winner each time the two crickets interacted in aggressive behavior. The loser was determined by which cricket backed up from the interaction first. After the ten minutes were up, the winner of the trial was the cricket with the most tallies. If the score was tied, the crickets were watched for an additional minute. This procedure was repeated twice for the remaining four crickets. A Chi-square test was used for hypothesis testing. This is used to determine that the observed number of wins of the resident from the trials is different from what would be observed by chance. The null hypothesis was observed wins will be equal to that expected by chance. On the other hand, the alternative hypothesis was observed wins will not be equal to that expected by chance. The class’ hypothesis was proven correct that resident male crickets have a greater motivation to defend