Heh, this thread makes me glad to live in New England. We keep our thermostat fairly low and the kitchen is particularly poorly insulated... but in the winter, we can get away with being fairly lax about putting food away and nothing happens to it. In the summer we can't do that (we don't have A/C, and the windows are usually open) but even still we don't usually see much worse than fruit flies or maybe a few ants.
Of course, on the other hand, we often wear hats in the house and heating a 20L tank for a BP requires an 80-watt RHP. But we don't need much in the way of pesticides!