I haven't tried enough species to come to a conclusion but my hypothesis is this:
If you can't grow one sundew from a particular area, you probably can't grow the rest from the same area.
D.capensis, the weed, SIMPLY WON'T grow well in Singapore. D.aliciae won't grow. D.regia too. These 3 are from S.Africa.
D.burmanni and D.spatulata from Asia do well here. D.intermedia and D.filiformis from USA are growing like crazy too.