Untitled - The Alfred Russel Wallace Website

4 i2 NOTES OF A BOTANIST CHAP.XXIV
This is a great advance on the views stated
" The ants
in the earlier letter, in which he wrote :
cannot be said to be useful to the plants, any more
than fleas and lice are to animals ; and the plants
have to accommodate to their parasites as best they
may." The evidence, however, now shows that, in
all probability, they are always useful, in which case
their becoming hereditary is merely a question of
variability in the plant, and the continued preservation
of those whose variations were in the direc-
tion of utility to the ants.
The whole of these very interesting phenomena,
so well described by Spruce, are thus seen to be in
complete accordance with those of the modification
of flowers by insect-agency, which are now admitted
to depend upon a mutual adaptation for the benefit
of both plant and insect.
They lead, I think, to the establishment of the
general principle, that no special adaptation
of one
organism to another can become fixed and hereditary
unless it is of direct utility to both.]