LATE LARVAL AND PREPUPAL DNA-SYNTHESIS IN IMAGINAL WING DISKS OF CALLIPHORA-ERYTHROCEPHALA

DNA sythesis in wing discs of Calliphora erythrocephala has been measured as a function of age during the last larval instar and the prepupal stage. As long as the larvae are kept in wet conditions the ratio of DNA synthesis to protein content decreases until a minimum has been reached when the larvae are approximately seven days old. As soon as the larvae enter a dry environment, or after treatment with 20-hydroxyecdysone, the ratio of DNA synthesis to protein content increases until a maximum has been reached at the beginning of the prepupal stage, after which a new decrease sets in. There appears to be an inverse relationship between the response to dry conditions or 20-hydroxyecdysone and the ratio of DNA synthesis to protein content in wing discs of larvae which were kept in wet conditions. In early pupae the ratio of DNA synthesis to protein content increases again. © 1979.