ANTS 143 



Food. Ants feed upon both animal and vegetable matter. 

 Their foraging raids extend over a radius of forty yards from 

 the nest. They often take food into the nest, and in cold 

 climates they hibernate during the winter. Much of the food 

 of the queen and Iarva3 is eaten by the workers and regurgi- 

 tated from the crop when they return to the nest. Ants have 

 a preference for sweet food, such as juices of fruits, sugar, 

 honey, and honeydew. Aphids secrete honeydew, and on that 

 account are cared for by the ants, taken into the ant nests 

 over winter, and in the spring carried back to the plants upon 

 which they feed. But the aphids are among the insects most 

 injurious to vegetation, and their protection by ants may be 

 of great economic importance to us. Watch the problem in 

 your own locality. 



Special senses. The organs of sight and hearing are very 

 slightly developed in the ant, but the sense of smell is espe- 

 cially keen. This sense is situated in the antennae. The ant 

 travels from its nest and finds the way back by the odor of 

 its own tracks. If a portion of the path the length of its own 

 body is disturbed, the ant is lost and wanders about until it 

 picks up the trail again, but a path left dry and undisturbed 

 can be followed by it five days later. Experiments show -that 

 its own nest is evidently detected at quite a distance by odor, 

 but the odor of other ants is supposed to be recognized only by 

 touching with the antennae. Each species of ant has a distinct, 

 characteristic odor. Different colonies also of the same species 

 differ slightly. In general, the odor of one species of ants is 

 offensive to those of another species, and causes aversion and 

 hostility. This is shown by well-defined warfare and slavery. 



Slavery. While most ants will capture and carry away 

 the young of another species whenever the opportunity is 

 offered, there are three species in America (Formica sangui- 

 nea, Polyergus rufescens, and Tomognathus americanus') that 

 plunder the nest of their enemy and rear the young as slaves. 



