Insects on Fringed Grass-of-Parnassus | Bob Armstrong's Nature Alaska

These flowers have five staminodes forming semicircles of stalked pseudonectaries each tipped with a yellowish glistening knob.
Although they are dry and rewardless, they attract many insects that probe at the tiny knobs.
What would be a benefit of having nectaries in which the insects received no benefits?
This means the plant still gets cross pollinated without having to produce anything to attract the insects.
To view the flower better and see the Thrips with pollen go to photos and type in fringed grass-of-parnassus in the search box.