Aedes aegypti is one of the most important disease vectors in the world.
So...what makes it a good vector, and why is it found worldwide?
This genus has a unique egg laying behavior. They lay their eggs on surfaces above water, and those eggs are dormant until the hole fills up.
One color form is dark, and doesn't hang out around people.
The second is lighter colored, and pretty much specifically feeds on people.
It's that second one which more or less took over the world.
So when the slave trade started up, Ae. aegypti was primed for worldwide invasion.
It was a hugely consequential disease, disrupting everything from agriculture to the Panama Canal.
In fact, Yellow Fever stopped the PC for 100yrs,
It's also *really* good at resisting pesticides, too. Lots of pops are resistant to DDT, etc.
Ae. albopictus is successful for many of the same reasons Ae. aegypti is, except one key difference.
So, with Ae. aegypti...something like 80-90% of bites are on people.
With Ae. albopictus, that number can be as low as 10%.
Albo spreads disease, but we'd rather have that over aegypti
In most areas where it's found, it's an invasive species. It's only native to sub-Saharan Africa.
If you want to learn more about the history of Ae. aegypti in your neck of the woods, this is an *excellent* article which covers most of the world outside my country.