CHAPTER 4
A N ANALYSIS OFTHE FACTORS INVOLVED I N
SY M BlOSlS
If the duration of any symbiotic relationship is examined, one can,
with some justification, divide the association into three phases, and as
the result focus critically on each. The phases I am proposing are:
(1) the period of initial host-symbiont contact ; (2) the establishment
of the symbiont on or within the host, and (3) the eventual escape of the
symbiont or its progeny so as to effect other similar associations. AS
outlined in Table I, each of these major phases can be subdivided into
several factors, each of which can be subjected to experimental or
observational analysis.
TABLE I. FACTORS WHICH MAY INFLUENCE THE PRINCIPAL PHASES OF
HOST-SYMBIONT RELATIONSHIP
A
B
C
Host-symbiont
Establishment of the
Escape of the
contact
symbiont
symbiont
1. Accidental contact
1.
2.
2. Contact dependent
3.
3.
4.
5.
6.
on host’s feeding
mechanisms
Contact influenced
4.
by chemotaxis
Contact influenced
5.
by other taxes
Selectivity by sym6.
biont
Influence of nature
7.
of substrate
Successful attachment
1. Active escape
Developmental stimuli
contributed by host
Host’s defense mech2. Involuntary escape
anisms
Symbiont’s nutritional
3. Passive escape
requirements
Role of host’s digestive
4. Cellular escape
enzymes
Host’s control of symbiont’s maturation
Pathological changes
induced by symbiont
Briefly, at least five factors could be considered as possible influences on host-symbiont contact : (1) the contact could be accidental ;
(2) it could be governed by the host’s activities during feeding or some
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