In general, species diversity, in general, increases from poles to the equator. With very few exceptions, tropics (latitudinal range of 23.5° N to 23.5° S) harbor more species than temperate or polar areas. The reason is that tropical environments, unlike temperate ones, are less seasonal, relatively more constant and predictable. Such constant environments promote niche specialization and lead to greater species diversity.
So, the correct answer is 'Species diversity, in general, increases from poles to the equator'.