Apparently it is my blood type or something, but I am constantly getting eaten alive by mosquitos. I grew up in rural Pennsylvania where they are common, so it was really annoying.
The science behind getting bit more or less depends on your ability to process cholesterol, your production of certain acids, and how much carbon dioxide you emit. Unfortunately, its mostly tied to genetics, so you and me are both screwed.
Slightly average body temperature, probably. I tend to get bitten a lot more than the people around me and run about half a degree above the 98.6 average normally. Good news is - the more you get bit, the less time the itch lasts for as you develop a bit of tolerance to it.