SOUTH-AMERICAN ORIGINS OF MICROCTONUS-HYPERODAE LOAN (HYMENOPTERA, BRACONIDAE) ESTABLISHED IN NEW-ZEALAND AS DEFINED BY MORPHOMETRIC ANALYSIS

Eight South American geographic populations of the thelytokous parasit oid Microctonus hyperodae Loan (Hymenoptera: Braconidae) were released in New Zealand in 1991 to assist in the suppression of the pasture pe st Listronotus bonariensis (Kuschel) (Coleoptera: Curculionidae). With one exception, parasitoids from each South American geographic popula tion were released in equal numbers at each New Zealand release site. It was postulated that the South American geographic population(s) bes t suited to the conditions encountered at each New Zealand release loc ality would eventually become prevalent there. A morphometric analysis of adult parasitoids of known South American origins, reported previo usly, allowed M. hyperodae derived from west of the Andes (i.e. two co llection sites in Chile) to be distinguished from parasitoids derived from east of the Andes (i.e. three collection sites in Argentina and o ne each in Brazil and Uruguay). Parasitoids derived from a fourth site in Argentina (S. C. de Bariloche) could not be clearly discriminated from either the 'east of the Andes' or 'west of the Andes' categories. A morphometric analysis of M. hyperodae adults collected from Jive of the New Zealand release sites from 1992-1994 is presented in this con tribution. The analysis indicated that parasitoids derived from east o f the Andes were significantly more prevalent than expected. The possi ble reasons for the initial success in New Zealand of one or more east of the Andes populations include the greater fecundity of M. hyperoda e collected in Uruguay and the likelihood that M. hyperodae from east of the Andes co-evolved more recently with the stock from which New Ze aland's L. bonariensis was founded.