Answer: partitioning of the butterfly due to available resources leading to a reduction in population in a particular location.
Step-by-step explanation:
What happen here is a reduction in population due to a reduced sharing of resources.
Two species of an Organism can not successfully occupy a space due to competition for available resources.
Here, the one population of checker spot is near the stem tip while the other population of checker spot butterfly is at the base of the stem to avoid competition for available resources and space. Hence, they live separately in the different position on the stem.