No Attack on Conspecifics by Soldiers of the Gall Aphid Ceratoglyphina bambusae (Homoptera) Late in the Season

Ceratoglyphina bambusae is the only aphid species whose soldiers are known to attack conspecifics. In a previous experiment carried out in September, when alates were not yet produced, soldiers attacked any insect but conspecific soldiers placed on the surface of their gall. The experiment was repeated on the same gall in December, when many alates were emerging : soldiers attacked virtually no conspecific aphid, so that alates took off without trouble. In another experiment carried out in June on a younger gall with fewer soldiers, not all but some non-soldiers were attacked. C. bambusae probably changes its tactics between September and December. It is suggested that even in September there are some galls whose defense against conspecific non-soldiers is by no means complete.