I believe it has to do with how warm or cool your skin is also.
I have heard blood type can be a factor. I read somewhere they tend to like type O blood
I haven't found that to be the case for me @A MyVitiligoTeam Member. That said, my wife (who does not have vitiligo) seems to get eaten alive when we go camping and I'm fine. so maybe having her sleep next to me is like my own bug protection!