The following chapters illustrate the intricacy of a two-CA system. The model in mind was a host parasite interaction. Soon it became evident that the relationship between the two CA was more intricate. The host developed parasite attributes, and the parasite displayed symbiotic features.
Experiment-1: Two isolated and non interacting CA a grown. Next, CA-1, the parasite encroaches upon CA-2, the host . Soon
CA-2 mounts its immune system and kills the parasite.
Experiment-2:
Host immunity is inbuilt in the CA structure The experiment investigates, whether the CA state at t = 40 is immunizing. Two
CA couples are involved. The first interacts in the same way as in the
first experiment. At t = 40 the immune host donates its state to the not immune host of the second couple.
Soon after transfer the parasite in the second couple dies, which shows
that the host became immune.
Experiment-3:
Compare the outcomes of immunity transfer at t = 20 and t = 40. Following both treatment the parasites
died, and the hosts became immune. The structure of the two parasites
differed. One was somewhat more robust, yet both ultimately died. The
outcome of immunization depends on the context of the host. Context is defined as set of
processes operating in the organism during immunization.
Experiment-4:
Explores the immunizing potential
of other states and contexts. State transfers between the two hosts were
done at rising times. Not all transfers ended in a successful outcome.
In some, CA-1 did not die, in others, CA-2 died. The experiment
evaluates only successful outcomes
Out of 62 transfers only 16 (=26%) conferred immunity.
Immunization confers more then just immunity.
The CA learns new strategies.
The different states of the donor CA-2 may be regarded as a library of actions , or a repertory, which
may be transferred to the recipient for different purposes. What is the
nature of the information
transferred from donor to
recipient? It is more than a
set of signals
Experiment-5:
Explores the effect of parasite removal on the system. The parasites were
killed at rising times. In 11 instances (=18%) CA-1 killing was followed by CA-2 death. Apparently the relationship
between CA-1 and CA-2 involves more than just a one way exploitation. In most cases
both CA gained. When CA-2 dies soon after CA-1 is killed it indicates
that during their brief encounter CA-2 benefited from a vital substance
produced by CA-1. Host responded
to parasite killing in three kinds of behavior: Partial dependency on
CA—1, Independence and mounting dependence.
The relationship between the two CA involves more than just a one way exploitation. Parasite and symbiont are not as distinct as is commonly viewed. Each host parasite relationship involves also symbiosis.