What causes cricket males to sing? Two consequences I can think of that come about from a male cricket's singing are the attraction of a female and the exhibition of aggression towards any other males present in the area. The act of singing accomplishes both of these tasks, but the question of which consequence led to the other comes up. In a lecture about evolutionary processes in a different class I learned about the mechanism and function of behaviors. The mechanism of a behavior is the actual process of the behavior and the direct results of this process, while the funcion of a behavior refers to the longterm consequences of the behavior, which are indirectly correlated to mechanism. If the mechanism of a behavior is evolutionarily successful, it follows that the function of that behavior will also develop by natural selection. Perhaps in this case, the initial mechanism of singing was used to warn other males in the area of the singing male's presence, since the traditional mating ritual may be preceded by a fight over the mating rights with the female between two competing males. This call eventually became associated by the female to the actual act of mating. Indirectly, the singing of the male lead to the attraction of the female who was interested in mating. The male who sang must have won enough competitions to have been selected for, so this became a pattern in behavior for crickets-the mechanism of singing to initiate or scare away competition led to the indirect function of attracting females interested in mating.

Fair enough, and important. But there is also a more immediate question. Why did THIS male cricket sing at THIS particular time? As we talked about in class today, that boils down to a question of whether there was an external triggering "stimulus", and hence to the interesting question: can a nervous system generate output irrespective of input? PG