Adaptation of Rodolia cardinalis (Mulsant) (Col., Coccinellidae) to lcerya aegyptiaca (Douglas) (Horn., Margrodidae) as compared with lcerya purchasi Mask

The Coccinellid  beetle, Rodolia  cardinalis (Mulsant), was introduced into Egypt in 1902 to control Icerya purchasi Mask. Developmental  stages of R. cardinalis have been found to be associated with populations of Icerya aegyptiacu (Douglas) on Ficus nitida trees in the Mansoura district of Egypt. The present work  throws  more light on the adaptation of this predator when feeding on Icer-ya aeg-vptiuca as compared with  feeding on I. purchmi. Choice of prey type was found to have a marked effect on egg coloration  but  appears to have no effect on hatching success or incubation  period. The development of R. cavdinalis larvae when reared  in  culture on I. aegyptiaca was  significantly faster than that fed on I. purchasi. The fecundity of R. cardinalis females was not affected by the prey type consumed as adults, and although  the longevity of males and females was shorter in association with I. purchasi, this difference was not significant. The results indicate that R. cardinalis is  well adapted to I. aegyptiacu in Egypt.