THE LIFE-CYCLE AND NATURAL-HISTORY OF THE TROPICAL APHID CERATAPHIS-FRANSSENI (HOMOPTERA, APHIDIDAE, HORMAPHIDINAE), WITH REFERENCE TO THE EVOLUTION OF HOST ALTERNATION IN APHIDS

We describe the life cycle and general biology of the tropical ceratap hidine aphid Cerataphis fransseni. We demonstrate that this aphid migr ates between trees of Styrax benzoin and various species of palms; pal m-feeding populations have previously been known as C. variabilis and C. palmae, which now become synonyms of C. fransseni. On S. benzoin th e fundatrix induces a relatively simple gall which can contain >6000 a phids at maturity with a large number of reproductively sterile soldie rs that protect the gall from predators. These galls are apparently pr oduced throughout the year. Colonies on the secondary host plants, pal ms, are apparently obligately tended by ants whereas colonies within g alls on Styrax are never tended by ants. We discuss the life cycle of this tropical aphid with respect to hypotheses for the evolution and m aintenance of host alternation.