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Origin Fair Copy p 23 Chap VII Instinct
Document Extent: 26 sheets   Folio Extent: 1 sheet

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185: 109a (22r)


Chap. VII Instinct.

«Slave-making instinct.--» We will now turn to the extraordinary slave making instinct of certain Ants. The Formica (Polyerges) rufescens «, as was first discovered by Pierre Huber, a better observer even than his celebrated father,» is absolutely dependent on its slaves. Wt1ithout their aid the species in a single year would certainly become extinct. The males and females do no work: and the workers or sterile females, though most energetic and courageous in capturing slaves, do no other work «when the community is once established.»> They are incapable of making their own nests or feeding their own larvæ: when their old nest is found inconvenient, and they have to migrate: it is the slaves which determine the migration, and actually carry their masters in their jaws. So utterly helpless are the masters, that when Huber shut up thirty of them without a slave, but with the food which they like best, and with their own larvæ and pupæ to stimulate them to work, they did nothing: they could not even feed themselves, and many perished of hunger with food close at hand. Huber then introduced a single slave (F. nigra «fusca» and she instsantly set to work fed and saved the survivors: male &

185: 109a (22v) Birds singing and insects flitting, watercolour by Francis Darwin or Horace Darwin

  • t1 W] written over 'w'
Reproduced by permission of the Syndics of Cambridge University Library and William Huxley Darwin
Transcription and apparatus © American Museum of Natural History