CHAPTER XII. 



ANT-NESTS. 



" Le premier objet qni frappe nos sens en commenqant a etudier les moettrs 

 des fourmis, c'esl 1'art avec lequel elles construisent leur habitation, dont la 

 .grandeur paroit souvent contraster avec leur petitesse ; c'est la variete de ces 

 batimcn>, tantot fabriques avec de la terre, tantot sculptes dans le tronc des 

 arbres les plus durs; ou composes simplement de feuillcs et de brins d'herbc 

 ramasses de toutes parts; c'est en fin la maniere dont Us repondent aux besoins 

 des especes qui les construisent." P. Huber, " Les Moeurs des Fourmis Indi- 

 genes," 1810. 



Nothing is better calculated to illustrate the marvellous plasticity 

 of ants than the study of their nesting habits. Not only may every 

 species be said to have its own plan of nest construction, but this plan 

 may be modified in manifold ways in order to adapt it to the particular 

 environment in which the species takes up its abode. Even the same 

 colony may adopt very different methods of building at different periods 

 in its growth and development. Hence the study of formicine archi- 

 tecture becomes one of bewildering complexity and defies all attempts 

 at rigid classification. Owing to this complexity it is impossible to 

 form a correct conception of the general plan of architecture in a par- 

 ticular species without studying its nesting habits throughout its whole 

 geographical range. In such a subject recourse to laboratory methods 

 is of little avail, whereas careful and extensive observation in the field 

 is all-important. 



One remarkable peculiarity of ant-nests impresses us at the very 

 outset when we compare them with the nests of the social wasps and 

 bees, namely, their extreme irregularity. The ants have abandoned, if 

 indeed they ever acquired, the habit of constructing regular anci per- 

 manent cells for their brood. The advantages of such cells to the ants 

 evidently do not outweigh the disadvantages of being unable to move 

 their larvre and pnpse from place to place when danger threatens or in 

 response to the diurnal variations of warmth and moisture. In its 

 essential features the typical nest is merely a system of intercommuni- 

 cating cavities with one or more openings to the outside world (Fig. 

 1 06). Even these openings, or entrances, as they are called, are absent 

 in the nests of hypogseic species, except at the time of the nuptial flight. 

 The intercommunicating cavities may be excavated in the soil or in 

 plants, and even preexisting cavities often answer every purpose and 



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