Passage I

When two male crickets encounter each other there is either a fight or a threat display. The dominant cricket usually forces the submissive cricket to retreat to a place of safety. A biologist conducted two experiments to investigate the formation of dominance hierarchies (rankings) in male crickets. In the experiments described below, five adult male crickets were placed together in a container, and their interactions were observed and recorded.

Experiment 1

To determine what factors might affect the formation of dominance hierarchies, the biologist recorded the sequence in which the crickets were placed in the container, their masses, their adult ages, and the number of chirps each cricket made during the experiment. In addition, the crickets were ranked according to their aggressiveness toward each other, from most aggressive (1) to least aggressive (5). The results are shown in Table 1.

Experiment 2

The crickets were placed back into the container in the same sequence as in Experiment 1. The results of all aggressive encounters between pairs of crickets were recorded. A cricket was declared a "winner" if it forced the other cricket, the "loser," to retreat. Table 2 shows the results of the interactions between the crickets.

Table 3 summarizes the results of all the encounters for each cricket.