THE ANTS OR PISMIRES 



ANTS AND OTHER ANIMALS 



Let us consider the relation of ants to the aphides and 

 mealy-bugs which provide much of the sugary part of the 

 diet of many species. This is what Zimmermann says about 

 the pineapple mealy-bug, a scale insect which causes very 

 serious losses in the pineapple plantations of Hawaii. 



Mealy-bugs become established on the pineapple planting 

 material during growth. These individuals persist on the future 

 plant sets while they are partially dried after trimming and can, 

 on occasion, even reproduce on this detached material. Hence, 

 a newly planted field may have a large initial mealy-bug popula- 

 tion. However, peculiar as it appears, most of these populations 

 disappear either because of the lack of adequate attending ant 

 populations or because of predator pressure or other causes. 

 The serious infestation of a new field comes from outside, 

 adjacent areas, especially old pineapple fields, waste or un- 

 cultivated lands. High infestations may build up from the out- 

 side within a period of six months. This movement is dependent 

 primarily upon the action of the attending ant Pheidole magace- 

 phala. If the ant populations are low, the subsequent mealy-bug 

 invasion of the fields will be slow and of low grade. If the ant 

 could be eliminated, the fields would be largely free of serious 

 mealy-bug infestation. Ants are essential for the proper develop 

 ment of mealy-bug colonies, for they tend them, shelter them, 

 protect them from parasites and predators and keep them clean 

 from detrius which, when massed with honeydew, has a 

 gumming-up and deleterious effect on the colonies. In short, 

 pineapple mealy-bugs have a difficult time maintaining them- 

 selves unless ant-attended. 



There is another side to this picture. According to 

 Clausen, the date-growers of the Yemen have for centuries 

 carried certain ants' nests to their orchards to protect them 

 against other ants. In China, the citrus-growers collect nests 

 of the red ant, Oecophylla, and put them in their trees, 



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