Searching and ovipositional behavior ofAmitus hesperidum [Hym.: Platygasteridae] andEncarsia opulenta [Hym.: Aphelinidae] parasitoids of the citrus blackfly [Hom.: Aleyrodidae]

Searching behavior ofAmitus hesperidumSilvestri andEncarsia opulenta (Silvestri) for immatureAleurocanthus woglumiAshby was similar. Both parasitoids moved unidirectionally until they encountered a host aggregation at which time they changed to a pattern of short walks with numerous turns. Parasitoid ovipositor insertion was generally at midbody between the host sternites and tergites.Amitus hesperidum females showed a significant preference for 1st instar hosts, have an ovipositional marker, do not feed on exudates from ovipositional wounds (host feed), and have significantly shorter ovipositional times and adult life spans thanE. opulenta which showed a significant preference for 2nd instar hosts, lack an ovipositional marker, and host feed.Encarsia opulenta females showed a significant preference for hosts previously parasitized byA. hesperidum but the reverse was not true. The average number of hosts parasitized by females of both parasitoid species was uninfluenced by the previous presence of the other parasitoid species on the same leaf.