BEHAVIORAL-FACTORS AFFECTING DIFFERENTIAL PARASITISM BY ANAGRUS-EPOS (HYMENOPTERA, MYMARIDAE), OF 2 SPECIES OF ERYTHRONEURAN LEAFHOPPERS (HOMOPTERA, CICADELLIDAE)

Explored the behavioural mechanisms underlying differential parasitism by an egg parasitoid, Anagrus epos, for 2 leafhopper hosts: a resident grape leafhopper (GLH) Erythroneura elegantula, and an invading variegated leafhopper (VLH) Erythroneura variabilis. A model for differential parasitism (also known as host preference) that takes into account the details of parasitoid foraging behaviour, and spatial heterogeneity of hosts within a patch, suggests that host encounter by parasitoids is unbiased, ie in direct proportion to host relative density, but that the parasitoid is unable to detect hosts of the invading VLH as well as those of GLH, probably because VLH eggs are buried deep within the leaf. The model and experimental design were also used to compare 3 different biotypes of A. epos, one of which has been imported from Mexico for possible use as a biocontrol agent, and which has both a higher likelihood of encountering and of detecting the invading VLH than do the California parasitoids. -from Authors