76 



KNOWLEDGE, 



[Apkil 1, 1892. 



THE LIFE OF AN ANT.-Il. 



By E. A. BuTLEK. 



THE exact nature of the occupations to which a 

 worker Ant devotes itself on attaining maturity, 

 depends somewhat upon the species, but there are, 

 as a rule, certain well-defined heads under which 

 their labours may be classed. Besides the care of 

 the young, which we have already noticed, their chief 

 duties will consist of the construction, enlargement, and 

 repair of the nest, the hunt for provisions, and the defence 

 of the colony. The satisfying of these claims will usually 

 be sufficient to occupy all their time, so that their life 

 becomes one of incessant activity, and their industry is 

 well known and proverbial. Their activity may extend 

 even into the night, for if daylight does not suffice to 

 complete necessary work, it must be continued after dark, 

 and Sir .John Lubbock mentions having watched an Ant 

 which worked continuously for nearly sixteen hours, from 

 early mornmg tiU late at night, carrying larva? to the nest. 

 The character and situation of the nest depend entirely 

 upon the species. The conical or rounded heap of earth 

 or twigs, commonly called an " Ant hill," is not always 

 present, nor does it follow that if Ant hills are made, each 

 distinct hillock represents a separate and independent 

 community. While it very frequently happens that an 

 entire community is located under one roof, such is by no 

 means universally the case, and, therefore, the terms " Ant 

 hill" and" Ants' nest" are not necessarily interchangeable; 

 often one colony will have three or four distinct dwellings, 

 in any of which its members would be at home. Occasionally 

 some communities build much more extensively than this. 

 M. Forel, indeed, cites a case in which a single community 

 of Ants of a very active species {Formica e.vsccta) possessed 

 as many as two hundred dwellings, which were spread over 

 a circular area measuring nearly a quarter of a mile in 

 diameter. So comjiletely had they appropriated this area 

 that, with the exception of a few nests belonging to a very 

 agile kind, no other species of Ant dared show their faces 

 in it. Many and fierce, no doubt, had been the conflicts 

 before this undisputed sway was established, for Formica 

 e.vsectii, though a delicate insect, is a ferocious fighter. Sir 

 •John Lubbock thus graphically describes its battles : 

 " They advance in serried masses, but in close quarters 

 they bite right and left, dancing about to avoid being bitten 

 themselves. When fighting with larger species, they 

 spring on to their backs, and then seize them by the neck 

 or by an antenna. They also have the instinct of acting 

 together, three or four seizing an enemy at once, and then 

 pulhng different ways, so that she on her part cannot get 

 at any one of her foes. One of them then jumps on her 

 back and cuts, or rather saws, off her head." 



While several Ant hills, as we have seen, may belong to 

 one community, it sometimes happens, on the other hand, 

 that a single hillock is shared by two communities, 

 belonging to distinct species, one half being occupied by 

 the one party and the remainder by the other, each main- 

 taining a separate organization, though domiciled under a 

 single roof. Thus the Yellow Ant (Lucius jiarusj, and one 

 of the races of the Bed Stinging Ant (Myrmica scahrinodix), 

 not unfrequently live side by side in this way, and the 

 distinctness of their establishments is evidenced by the 

 fact that if the nest be disturbed, as for example by the 

 dislodging of a stone, the two parties on rushing out to 

 discover the cause of the disturbance will sometimes come 

 into conflict, and a desperate struggle will take place, each 

 apparently mistaking the other for the authors of the 

 disaster. But there is another way in which a single Ant 



hill may shelter more than one species. Small and weak 

 species sometimes live in the nests of larger and more 

 powerful ones, completely intermixed with them, though 

 the bond of connection is not always the same. There is 

 a minute Ant called Stenomnia M'esiirtiodii, which is never 

 found except in the nests of the Wood Ant and an allied 

 species, and so dependent do they seem on their hosts, 

 that when the latter change their abode, their little 

 companions go with them. They are certainly not on 

 terms of hostility to the larger species, which, indeed, take 

 but little notice of them. Not so, however, with another 

 minute Ant called Solmopsis fiit/ax ; these are real parasites; 

 they make galleries in the walls of their hosts' nests, 

 whence they issue to invade the nurseries of the latter and 

 carry off the young as food. Once within their galleries, 

 they are safe from retribution at the hands of their 

 defrauded hosts, as the latter are too large to get into their 

 tiny burrows. Sir .John Lubbock has very aptly compared 

 their depredations to what would be the state of affairs 

 with us, "if we had small dwarfs, about eighteen inches 

 to two feet long, harbouring in the walls of our houses and 

 every now and then carrying off some of oui- children into 

 their horrid dens." 



But further, a smaller and weaker species may be in 

 the nest of a larger one as slaves, or at any rate, helpers. 

 Though the most remarkable of the slave-making species 

 are not British, we have in this country one kind which 

 is addicted to such habits. It is very much like the Wood 

 Ant {Formica rufa), and is sometimes called the Eed iVnt, 

 (F. MDu/uinea). (Fig. 4.) The worker has a red head and 



Fig. 4. — Formica sangnhiea. Female. A slare-lioldino; Ant. 

 Magnified 4 diameters. 



thorax, and a black body ; it makes raids upon neighbouring 

 nests of different species, capturing those larvfe and pupfc 

 which will produce workers. These, on coming to 

 maturity, finding themselves surrounded only by members 

 of a different species, and having no young of their own to 

 look after, calmly submit to their fate, adapt themselves to 

 their circumstances and set to work to tend the young of 

 their captors. In all Ants, the feeding of the young seems 

 to be the first work to which newly-matured workers devote 

 themselves, and it is certainly the most suitable employ- 

 ment for them until their skins are sufficiently hardened to 

 make them fit to go out on foraging expeditions, when 

 they may have to fight for their own lives or for those of 

 their brethren. The practice of keeping slaves or assist- 

 ants, of an inferior race, has not advanced in F. sanguinca 

 to such an extent as it has in some foreign species, where 



