Wasps, Bees, and Ants 



495 



Exceptions are those species which live as guests of other wasps, or as para- 

 sites on other insects. 



The habit common to almost all of the solitary wasps of so stinging the 

 prey, caterpillars, spiders, beetles, flies, bugs, or whatever other insects 

 are used to provision the nests, as not to kill but only to paralyze it, is perhaps 

 the most amazing part of all the interesting behavior of all these wasps. 

 The advantage is obvious: killed, the prey would quickly decompose, and 

 the hatching carnivorous wasp larva would have only a mass of, to it, inedible, 

 decaying flesh instead of the fresh live animal substance it demands. But 

 if stored unhurt, the prey would, if a cricket or spider or similarly active 

 animal, quickly escape from the burrow, or if a caterpillar or weak bug, at 

 least succeed, albeit unwittingly, in crushing the tender wasp egg by wrig- 

 gling about in the underground prison-cell. More than that, unhurt, some 

 insects could not live without food the many days that are necessary for 

 the development of the wasp larva, especially in the face of the frantic and 

 exhausting efforts they would be impelled to in their attempts to escape. 

 But paralyzed, there is no exertion, metabolism is slight, and life without 

 food is capable of being prolonged many days. The paralysis is due to 

 the stinging by the wasp of one or more of the ganglia (nerve-centers) 





Fig. 698. — Cerceris luberctilata, dragging weevil {Cleonus sp.) to nest. 

 (After Fabre; natural size.) 



of the ventral nerve-cord. With a wasp species (Sphex flavipennis) observed 

 by Fabre,* which provisions its nest with crickets, each cricket was stung 



* Fabre, J. H., Insect Life, 1901. 



