Most insects with wide ranges break into local populations that diverge genetically, because few individuals cross the barriers between them. The globe skimmer does not. Samples from locations on different continents come back with mitochondrial and nuclear markers so similar that they are best read as a single interbreeding population.
The behaviour behind that pattern is long-distance flight on prevailing winds. Globe skimmers ride seasonal wind systems, gliding on broad hindwings rather than flapping continuously, which makes the crossing energetically cheap. Swarms appear over open ocean and on islands hundreds of kilometres from the nearest breeding water, and the timing of arrivals tracks the movement of the rain belts the species depends on for its temporary breeding pools.
One widely repeated figure, an individual round trip of about 18,000 kilometres across the Indian Ocean, is inferred from wind patterns, arrival timing and isotope evidence, not from tracking a marked dragonfly the whole way. The genetic uniformity is solid; the exact route any single insect flies is not.