ANALYSIS O F PROCESSES I N CONTROL O F INSECTS
5
it is simply an effect of the relaxation of the active psocess. The principle
of this action is the same as that of the governor on an engine; it is the
cybernetic principle of negative feed-back. Thus it can be said that
I
I
I
I
I
I
0100
200
300
400
500
Larvae per 1OOsq. ft. of foliage
FIG. 2. Graph of data tabulated by Morris (1959) for larval population density and yo
parasitism of the black-headed budworm, AcZeris variana (Fern.) (Tortricidcte) by a
complex of Ichneumoid and Tachinid parasites, in successive generations in a stand of
conifers in northern New Brunswick.
I
I
I
I
I
!
0
100
200
300
400
500
Lorvol populotion of previous generation, per IOOsq. ft. of foliage
FIG. 3. The same data as Fig. 2, but current yo parasitism graphed against host population density in the previous generation, showing (delayed) density-dependent relationship.
5
it is simply an effect of the relaxation of the active psocess. The principle
of this action is the same as that of the governor on an engine; it is the
cybernetic principle of negative feed-back. Thus it can be said that
I
I
I
I
I
I
0100
200
300
400
500
Larvae per 1OOsq. ft. of foliage
FIG. 2. Graph of data tabulated by Morris (1959) for larval population density and yo
parasitism of the black-headed budworm, AcZeris variana (Fern.) (Tortricidcte) by a
complex of Ichneumoid and Tachinid parasites, in successive generations in a stand of
conifers in northern New Brunswick.
I
I
I
I
I
!
0
100
200
300
400
500
Lorvol populotion of previous generation, per IOOsq. ft. of foliage
FIG. 3. The same data as Fig. 2, but current yo parasitism graphed against host population density in the previous generation, showing (delayed) density-dependent relationship.