Simultaneous Care of More Than One Nest by Ammophila Azteca Cameron (Hymenoptera, Sphecidae)

In attempting to, trace the o,rigin of social behavior among wasps, in his Social Life Among the Insects (I923) William. Morton Wheeler selected Ammophila as "a paradigm ot the whole group of Sphecoids and solitary Vespoids". Were he alive to.day, and able to utilize all the considerable knowledge o.f this genus gained in the last three decades, it seems likely that he would embrace, Ammophila even more enthusiastically as a paradigm not only o.f the. solitary wasps but of several preliminary stages in the. origin of s.ociality. It has been shown by Evans. (I958, I959) and by Powell (I964) that the North American species ot this genus which have been studied can be arranged in series as tollows: () strictly solitary species which utilize a single large caterpillar per nest, (2) species which mass-provision with two to several small .caterpillars, (3) spec!es in which provisioning is. commonly "delayed" such that the last prey is brought in after the. egg has hatched, and (4) species employing progressive provisioning regularly. Several other aspects ot behavior are roughly correlated with this progression: for example, species using smaller .caterpillars usually carry the prey in flight, and these same species generally carry the so.il of excavation away from the nest in flight. Also, most records o.f gregarious nesting pertain to species employing progressive pro.vision.ing. It is apparent that the European species can be. arranged in a very