Life History and Sex Determination in the Diaspine Scale,Pseudaulacaspis pentagona(Targ.) (Coccoidea)

Abstract

The increasing body of knowledge about the armored scales is beginning to reveal manv unique aspects in the life cycles of these highly specialized insects. Such information is not only of value to the entomologist and those concerned with the control of scales but is also becoming important in such diverse fields as genetics, ecology, cytology, and physiology; armored scales may well find an expanding place in the laboratory as subjects for researches in a variety of fields.Pseudaulacaspis pentagona(Targ.) has one of the most unusual, yet to date one of the best understood life cycles of the armored scales. Various aspects of its biology have been described by Berlese (1910), Smit (1953), Dustan (1953), and Monti (1955). Accounts of its natural enemies or biological control programs have been given by Berlese (1910) for Italy, by Ogilvie (1928) and Simmonds (1955) for Bermuda, by Bennett (1956) for Trinidad, and Clausen (1956) for Florida.P. pentagonais a pest of economic importance on a wide variety of hosts throughout an extekive geographic distribution (Anon., 1956), and has been cultured extensively in the biological control laboratory for the mass-rearing of scale parasites and predators. Recent investirzations of the sex determining mechanik and chromosome behaviour (Brown and Bennett, 1957) have arain shown unusual processes and relationships, some of which appear to occur in many other species of armored scales. It is the purpose of this paper to describe the life cycle ofP. pentagonaas it is known from field and laboratory studies and from cytological and genetic investigations.