spiciness is chilli pepper's best defense against seed attacking microbes.but not all chillis are hot, because producing that heat comes at a price.so says a study in journal proceeding the royal society b.researchers look at wild chilli populations along a 185 miles * in southern Bolivia as climate goes from wet to dry.as it said, they taste tested chillies for heat,later they analysed samples for concentrations of *,spicy stuff. turns out only a 1/5 of chilli plants in dry region have heat. but in wet areas all the chillis will become there.because that's where fungi attack the peppers. and chillis need chemical weapons to protect their seeds.but there is a cost for that defense,spicy chilli plant in this study use water far less efficiently. during the period of drought, they produce only  half as many seeds as their mild cousins. as for home gardeners hoping to grow spicy chillies,don't figure on simply watering your garden one.the authors say dislike the spicy gene you have to tend that pepper patch for 20000 generations.