The Biting Powers of Ants 



I'.v w. 1-. .M ( A T i: !•: 



liiilcd Slati's Bioloi;i<'.'il Survey 



IF Till'; title Ii;h1 not l.cfii to.) loiiy, not to 

 say jiodaiitu', this papor iiiiy;lit well liavo 

 boon lioailod "The Natural and Artificial 

 Uses of tho Maiiilihiilar I'owers of Ants," 

 neither would it have been amiss to entitle 

 it "l^ses and Misuses of Ant .laws." 



.laws iiuiy he used for many tliinj^s, and 

 so indeed they must, in the case of most 

 invertebrates, as in addition to the normal 

 functions connected with eating, the Jaws 

 form the sole means of prehension, and 

 therefore are the most important medium 

 of contact of the organism Avith its en- 

 vironment. Mandibles are hands and tools 

 in one, but they have many special uses, ;ind 

 this is particularly true of the order of in- 

 sects to which ants belong. 



It is well known that many of this group 

 (Hymenoptera) maintain tluir position 

 while sleeping, or in other words, keep them- 

 selves in bed, by the use of the mandibles. 

 In Texas two species of bees resort regu- 

 larly to certain trees for sleeping and firmly 

 insert their jaws into the wood.i At a 

 hymenopterous "hotel" at Falls Church, Vir- 

 ginia, two species of bees and three of 

 wasps were observed to sleep on grass stems 

 which they grasped tightly with their man- 

 dibles.2 Enough similar observations have 

 been made to prove that this is a more or 

 less general habit, not onl)' of species in the 

 United States but also of those in other 

 countries. Parasitic Hymenoptera have been 

 found attached by the jaws to their host 

 insects, apparently awaiting a favorable 

 opportunity for oviposition. This has been 

 especially noted in the genus Scelio, Avhich 

 deposits its eggs in those of grasshoppers. 



Proceeding to ant "jaAvology" in particu- 

 lar, we may best divide the discussion into 

 (1) The biting poAvers of ants as used by 

 themseh'es in their own, or Avhat they con- 

 sider their OAvn, affairs, and (2) The use by 

 other animals of these poAvers of ants. In 



' Observation of Mr. E. A. Schwarz. 

 " Fact reported by Mr. Nathan Banks. 



the |iiiisiiit of their ac<'nstoMiei| activities, 

 ants naturally use their Jaws chielly in ways 

 advantageous to themselves, but good things 

 often are carried too far, and ants in using 

 their JaAvs furnish no exception to the rule. 

 \\r therefore have a category of actions 

 wliirli are di.sad\'antageous. 



The advantageous uses of the jaws form 

 a i)art of most of the normal activities of 

 ants: "The mandibles, being the parts Avith 

 Avhicli the ant comes into most effective rela- 

 tions Avith its environment, present, like the 

 beaks of birds and the teeth of mammals, a 

 bcAvildering variety of structure. They are 

 used for excavating soil or Avood, cutting up 

 the food, fighting, carrying the prey, their 

 young, or one another, and in some species, 

 even in leaping by closing them rapidly 

 against hard bodies. Ants are remarkable 

 in being able to open and close their man- 

 dibles independently of the maxilla? and 

 lal)iuin."'' 



Mandibles of the normal type "are pal- 

 mate, toothed along the receding edges, and 

 terminate on the inside margin in a large 

 pointed tooth or tusk. These tAvo opposed 

 instruments, Avorking against each other, 

 form the composite tool and Avar Aveapon of 

 ants. With these they dig their galleries in 

 the earth, or carve them out of Avood, cut 

 doAvn grass, defoliate trees, seize and cut up 

 food of all sorts. Being palm-shaped as a 

 rule, the gathered and comminuted material 

 can be compressed into their holloAvs, and so 

 carried as conveniently as in a basket or bar- 

 roAv. As the muscles permit the application 

 of much or little force at the insect's will, 

 the mandibles can be clamped together with 

 poAver enough to break and tear tough fibres, 

 or approximated so gently that the soft 

 eggs and tender larvae can be borne about 

 as daintily as an infant in a mother's 

 arms."* 



Ever}' one has obserA'cd trees that have 



'Wheeler, W. M.. Antu, 1910, pp. 18-19. 



* McCook, H. C, Ant Communiliea, 1909. p. 206. 



* This article by Mr. McAtee Avas prepared originally to be read before a learned body of scientific 

 men, the Biological Society of Washington ("for their amusement," Mr. McAtee explains); it neverthe- 

 less obtrudes no technicalities of language or distracting bibliographical references — although presenting 

 through frequent footnotes the authority for every statement and the original sources for further re- 

 search liy thp interested student. — The Editor 



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