Bugs, especially mosquitos, are more prevalent when it's rainy and in low-lying areas without a breeze. You will tend to get a lot of bugs a couple weeks after heavy rains, and Oct./Nov. statistically is the rainiest time of year in the BVI.

Mosquitos don't fly well against the wind, so an elevated property with good breezes is less likely to be buggy. Conversely, a low-lying property with a lot of brush around will be buggy. So no island is buggier, per se, but avoid a damp, low-lying area protected from prevailing wind.