Wild-type Drosophila have a pair of wings on one segment and a pair of halteres on the adjacent posterior segment. Wild type four-winged insects like dragonflies do not have halteres. Ultrabithorax (Ubx) is a homeobox gene. Ubx mutants of Drosophila have two pairs of wings and no halteres. In relation to Ubx function, the two-winged and four-winged insect species differ based on
1
Ubx expression levels in segments that give rise to wings/halteres.
2
Ubx regulation at different developmental times in segments that give rise to wings/halteres.
3
targets of Ubx in segments that give rise to wings/halteres.
4
Ubx copy number and paralog evolution.