At one point, the entomologist collects an antlion. This insect is from the family Myrmeleontidae. The larval stage is often called a "doodlebug" in the United States. The insect ensnares its prey by digging out a pit in loose sand. When the prey falls into the pit, it is unable to get out and becomes food for the antlion. This is symbolic of the situation the entomologist himself encounters when he is trapped in the sand pit.
Kyôko Kishida and director Hiroshi Teshigahara had a number of artistic differences in the film, ranging from Kishida's character's manner of dress to her symbolic importance. Kishida wanted to portray her character as a universal "every-woman" while Teshigahara insisted that her character was uniquely Japanese. Teshigahara's vision eventually won out.