Pieris brassicae,a Palaearctic pest introduced into Chile about 1970, co‐occurs spatially and temporally with three native Pierini of the genusTatochila.The habit ofP. brassicaeof laying eggs in large masses on large, succulent hosts effectively prevents competition for hosts withT. mercedisandT. blanchardii,both of which oviposit singly on small, slender Cruciferous hosts. The early stages ofT. theodiceare unknown, but it is apparently not a Crucifer feeder.P. brassicaeappears to have filled a “vacant niche”; created by the naturalization of robust, weedy European Crucifers in Chile.