Thus I believe it has been with social insects: a slight
modification of structure, or instinct, correlated with the sterile
condition of certain members of the community, has been advantageous
to the community: consequently the fertile males and females of the
same community flourished, and transmitted to their fertile offspring
a tendency to produce sterile members having the same modification.
And I believe that this process has been repeated, until that
prodigious amount of difference between the fertile and sterile
females of the same species has been produced, which we see in many
social insects.
But we have not as yet touched on the climax of the difficulty;
namely, the fact that the neuters of several ants differ, not only
from the fertile females and males, but from each other, sometimes to
an almost incredible degree, and are thus divided into two or even
three castes. The castes, moreover, do not generally graduate into
each other, but are perfectly well defined; being as distinct from
each other, as are any two species of the same genus, or rather as any
two genera of the same family. Thus in Eciton, there are working and
soldier neuters, with jaws and instincts extraordinarily different: in
Cryptocerus, the workers of one caste alone carry a wonderful sort of
shield on their heads, the use of which is quite unknown: in the
Mexican Myrmecocystus, the workers of one caste never leave the nest;
they are fed by the workers of another caste, and they have an
enormously developed abdomen which secretes a sort of honey, supplying
the place of that excreted by the aphides, or the domestic cattle as
they may be called, which our European ants guard or imprison.
Pages:
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294