The viability of the parasitoids was calculated from the subset
of larvae that were sufficiently healthy to allow the development
of at least one adult wasp. This was measured as ‘‘adult recovery’’,
which describes the proportion of adult wasps recovered from the
total number of eggs present on a parasitized larva (Table 2).
Comparisons between the no-choice and choice studies found no
consistent viability differences with the corn diet. In the no-choice
study the two strains were essentially equivalent (72% and 70%),
while in the choice study, adult recovery in the rice-strain was
higher (85%) than in the corn strain (68%) (Z = 1.58; P = 0.05).