THE EFFECTS ON GENETIC-VARIABILITY FOLLOWING A RECENT COLONIZATION EVENT - THE AUSTRALIAN SHEEP BLOWFLY, LUCILIA-CUPRINA ARRIVES IN NEW-ZEALAND

The Australian sheep blowfly, Lucilia cuprina, was first identified in New Zealand in 1988 and is now found to have spread throughout many s heep-farming regions. L. cuprina is estimated to have been present in New Zealand < 20 years, while in Australia L. cuprina has been estimat ed present > 100 years. The aim of this study was to determine the gen etic effects of colonization of L. cuprina and to compare populations of L. cuprina from these two countries in terms of genetic variability and differentiation. Allozyme electrophoresis was used which revealed variability at six loci. 1680 blowflies were examined from 56 sites t hroughout L. cuprina's range in both countries. Genetic variability at each locus in terms of allele composition was found to be high and ge netic differentiation varied considerably in New Zealand in comparison to Australia. Temporal sampling in New Zealand suggests seasonal fluc tuations of population size in the recently colonized region of the So uth Island.