Answer:
It is expected that the introduced population decreases because they have a minor adaptive response to survive in this new environment in comparison to its competence (i.e., specialized populations of soapberry bugs).
Explanation:
Natural selection is represented by the evolutionary processes that will select for survival to those individuals with higher adaptive fitness, which in this case is represented by the ability to obtain resources (food). In concequence, and according to the evolution theory, these introduced individuals will have less chances to reproduce in order to perpetuate their genes in the next generation.