The overall level of parasitoid attack on the apple fly race calculated from the 1991 eclosion data was 10.6% (56/528 = eclosing parasitoids/[eclosing parasitoids + eclosing flies]) compared to 58.3% (848/1454) for the hawthorn race.
melleus population has shifted its eclosion pattern to utilize apple fly larvae as a new host resource.
Estimates of parasitism from Experiments I-III were therefore roughly equivalent, although the mean level did drop significantly between the field eclosion and the tent rearing experiments for the apple fly race (16.4% [n = 2139 eclosing parasitoids and flies] compared to 12.8% [n = 1493]; G = 9.2, P = 0.0026, 1 dr) and between the tent rearing and fruit dissection experiments for the hawthorn fly race (44.9% [n = 1267 eclosing parasitoids and flies] compared to 40% [n = 8773 puparia dissected]; G: 86.3, P [less than] 0.0001, 1 df).