Effects of diet on development and reproductive fitness of two predatory coccinellids (Coleoptera: Coccinellidae)

Studies of prey suitability are needed to develop efficient mass rearing programs for generalist predators and to understand their potential contribution to integrated pest management. A laboratory study was conducted to evaluate the development and reproductive success of two predatory coccinellids, Oenopia conglobata (L.) and Cheilomenes sexmaculata (Fabricius), reared on diets of the common pistachio psyllid, Agonoscena pistaciae Burckhardt & Lauterer, the cotton aphid, Aphis gossypii (Glover) or a reference diet of Ephestia kuehniella Zeller eggs. Development and reproductive performance of the two coccinellids varied with diet, but egg fertility and immature survival did not. The developmental period (egg-adult) was shortest for both species on A. gossypii. This prey also yielded the shortest preoviposition period and greatest fecundity for C. sexmaculata. The psyllid diet was superior for reproduction in O. conglobata. For both predators, eggs of E. kuehniella were a better diet for development than for reproduction. Life table data indicated that the arboreal O. conglobata was better adapted to A. pistaciae on pistachio trees and might be a more effective biocontrol agent for this pest, despite the fact that C. sexmaculata had a higher intrinsic rate of increase on all diets.