Linked from
The 29 pages that link to Drosophila melanogaster, each with the reason it gives.
DipteraBroader topic: This species makes the order’s experimental value especially visible.
InsectaBroader topic: Research on this insect has helped reveal mechanisms shared across animals.
InvertebrateBroader topic: This invertebrate has helped reveal mechanisms shared across animals.
ProtostomeBroader topic: This ecdysozoan model reveals conserved mechanisms of animal development.