Survey of Aphis Gossypii on Crop Plants

Tests were conducted to determine if age of mass reared adult female Mediterranean fruit flies, Ceratitis capitata (Wiedemann), affected the viability of their offspring. Samples of eggs (0.4 g each) were collected on five consecutive days (4 to 8 d past adult emergence) from individual 660-liter adult colony screen cages and were reared in separate trays containing 0.5 liter of artificial diet. The mean volume of pupae obtained declined steadily with the age of the parents from 297 ± 21 (S.E.) ml per liter of larval diet for day 1 eggs to 158 ± 24 ml/liter for day 5 eggs. Hatch of eggs varied little, indicating that the viability of larvae declined with maternal age. The yield of pupae also varied significantly among replicates (adult cages), ranging from 174 ± 24 to 258 ± 23 ml per liter of diet. In a second test, pupal yield again declined with maternal age, whereas giving females a “break” from oviposition by withholding egging substrates on various schedules had no discernable effect on the relationship between age. In a second test (but not the first), maternal age also had significant effects on a number of quality traits in the progeny, including percentages of hatch, adult emergence, and flight ability. The authors propose that the observed cross-generation effects on insect survival and quality are likely a maternal effect and discuss possible implications of the findings for mass rearing operations.