SPECIFICITY AND INSTAR PREFERENCE OF DIPLAZON LAETATORIUS (HYM. ICHNEUMONIDAE) PARASITIZING APHIDOPHAGOUS SYRPHIDS (DIPT. SYRPHIDAE)

D. laetatorius is one of the most important natural enemies of aphidop hagous syrphid flies, in terms of abundance, in crops and pastures in Argentina. In order to increase the database on this parasitoid, its p rey selection behaviour was studied. Laboratory experiments were made to investigate its preference of host species and instars within speci es. This parasitoid showed a fastidious behaviour, choosing more often than predicted by chance, first instars of Allograpta exotica (Wied.) .