WiLT: Fruit Flies
The are two species of fruit flies in Pennsylvania, one that feeds on blueberries, and one that feeds on snowberries. Not that odd, huh? well, if these two fruit flies breed, the hybrid offspring is not genetically compatible with either parent species, but is able to reproduce with other hybrids of the same heritage, and feeds on honeysuckle, not blueberries or snowberries.
Wierd, huh?