Origin of Species Variorum

→ an image of despair over 1872

over 1859

an image of despair, over 1860 1861 1866 1869

→ few: 1872

few. 1859

few: the masters determine when and where a new nest shall be formed, and when they migrate, the masters carry the slaves. 1860 1861 1866 1869

→ OMIT 1861 1866 1869 1872

I can see no difficulty in 1859 1860

booty, for about forty

yards,

yards

back, to

a very thick clump of heath, whence I saw the last individual of F. sanguinea emerge, carrying a pupa; but I was not able to find the desolated nest in the thick heath. The nest, however, must have been close at hand, for two or three individuals of F. fusca were rushing about in the greatest agitation, and one was perched motionless with its own pupa in its mouth on the top of a spray of

heath

heath,

→an image of despair over its ravaged home.

Such are the facts, though they did not need confirmation by me, in regard to the wonderful instinct of making slaves. Let it be observed what a contrast the instinctive habits of F. sanguinea present with those of the

continental F.

rufescens. The latter does not build its own nest, does not determine its own migrations, does not collect food for itself or its young, and cannot even feed itself: it is absolutely dependent on its numerous slaves. Formica sanguinea, on the other hand, possesses much fewer slaves, and in the early part of the summer extremely →few:

The

the

masters determine when and where a new nest shall be formed, and when they migrate, the masters carry the slaves. Both in Switzerland and England the slaves seem to have the exclusive care of the larvæ, and the masters alone go on slave-making expeditions. In Switzerland the slaves and masters work together, making and bringing materials for the

nest:

nest;

both, but chiefly the slaves, tend, and

milk

milk,

as it may be called, their aphides; and thus both collect food for the community. In England the masters alone usually leave the nest to collect building materials and food for themselves, their slaves and larvæ. So that the masters in this country receive much less service from their slaves than they do in Switzerland.

By what steps the instinct of F. sanguinea originated I will not pretend to conjecture. But as ants, which are not

slave-makers,

slave-makers

will, as I have seen, carry off

pupæ

the pupæ

of other species, if scattered near their nests, it is possible that

pupæ

such pupæ

originally stored as food might become developed; and the

ants

foreign ants

thus unintentionally reared would then follow their proper instincts, and do what work they could. If their presence proved useful to the species which had seized them— if it were more

advan- tageous

advantageous

to this species to capture workers than to procreate them— the habit of collecting

pupæ

pupæ,

originally for

food

food,

might by natural selection be strengthened and rendered permanent for the very different purpose of raising slaves. When the instinct was once acquired, if carried out to a much less extent even than in our British F. sanguinea, which, as we have seen, is less aided by its slaves than the same species in Switzerland, →OMIT