Studies on Marietta carnesi (Hymenoptera: Aphelinidae), A Hyperparasite of Diaspine Scales (Homoptera: Diaspididae)

Abstract

This study was carried out to clarify the primary hosts of Marietta carnesi and its host relationship. In Fukuoka and Miyazaki, Aonidiella taxus was parasitized by Comperiella bifasciata, Aspidiotiphagus citrinus, Aphytis sp. A and two species of Prospaltella, whereas, Chrysomphalus bifasciculatus by C. bifasciata and Aphytis sp. B. All of these primary parasites were attacked by the hyperparasite, M. carnesi. This hyperparasite was determined to be a “direct secondary parasite” as defined by Flanders (1963). However, it deposits its eggs in a different manner between generations. From spring to autumn, the eggs are laid on or near pupae of primary parasites, whereas the overwintering eggs are deposited on the living adult scales containing young larvae of primary parasites, and never on scales which had not been parasitized by any primary parasite. This seems to be an evolutionary adaptation for hibernation of this hyperparasite. Two types cf intraspecific competition, i.e. phenomena of superparasitism and autoparasitism, were observed. Auto-parasitism seems to play an important role for density regulation and maintenance of its population, when abundance of the hyperparasite overwhelmed the primary parasite. © 1972, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.