There are two events,
A: the selection belongs to the specific species, or
A' : the selection does not belong to the specific species.
There are so many examples for that in different areas, like TPT1 experiment carried out in our lab recently.Here's one link: http://www.alfa-chemistry.com/tpt1-cas-167218-46-4-item-290583.htm
This is parasitism because one organism (mosquito) is benefitting (by acquiring nutrition) and the other organism (human) is harmed (by the red itchy bump).
What pair of integers? You haven't provided any.
