Final answer:
The heritability of parasitism success in wasps was studied by Heather Henter with a crucial aspect of the experimental design being the use of a single clone of aphid hosts to minimize host genetic variability.
Step-by-step explanation:
When Heather Henter studied the heritability of parasitism success in wasps, a crucial component of her experimental design was that the aphid hosts represented a single clone.
The use of a single clone of aphid hosts would ensure that the genetic variability among the hosts was minimized, allowing for any observed differences in parasitism success to be attributed more credibly to genetic differences among the wasps themselves rather than variability in the hosts' resistance. This approach is key in understanding whether specific traits associated with parasitism success are heritable within the wasp species being studied.