This movie is based on a very popular manga in Japan. One of the possible reasons for its popularity might be that in Japan many children grow up being "fans" of insects in the same way that some kids are "fans" of dinosaurs. A lot of Japanese kids have a deep knowledge about different kinds of bugs.
Several times we see the drinking bird and the glass of water: a direct homage to the Alien (1979) franchise.
Shokichi's name is also the word used to describe a level of luck/blessing in O-mikuji (New Years Day fortune paper).