"Other than predation, parasitism offers an extremely fascinating case because it is in here that we see the overlapping and interface of two Umwelten, that of the parasite and that of the host. From a casual observer’s point of view, the parasite and the host, so long as they reside together, can be said to share one world from which is constructed two interlocked Umwelten.(..)
I would like to reinstate an old semiotic model of value exchange developed from A. J. Greimas’s structural semantics (1983; 1987). For the para-site, the value consists of two elements, nutrition and habitat. If we retain Uexküll’s preferred nominal for the living organism as subject rather than object (Uexküll 1926: 126), then the values it “desires”, out of biological instinct, such as medium and food, serve as its object. This subject-seeking-object process then forms an elementary syntagmata in signification, comparable to Uexküll’s interaction of world as sensed by a subject and its world of action. This subject-object relation is coupled with another sender-receiver relation, thus constituting the communicative-performative syntagm of living organisms. The exchange of value may first seem to be unilateral in that the host serves only as sender (expéditeur) and the parasite receiver (destinataire); but one could expand the realm of value to include other information-contents or messages, such as immunity, then the communication becomes bilateral or reciprocal. In fact, the relation-ship of sender and receiver can be reversed, depending on the contents of information emitted from the sender, be it food-resource or survival threat. This act of communication takes place in the shared Umwelt of the two subjects, or in the interfacial space of two Umwelten, and is performed by two actants in a reciprocal operation."
2003: Han-liang Chang
Dept. of Foreign Languages and Literatures, National Taiwan University
