This is only because Dusek is trying to confuse the jury with tedious questioning. During the direct examination by Feldman, Faulkner stated that based on the fly maggot/larva evidence, the latest date the body could have been placed at the scene was 10-12 days before it was discovered.
Based on the lack of beetle larva, Faulkner stated that the body could not have been placed there within a time-frame that could implicate DW a having disposed of the body. The body, based on the beetle evidence, was placed there well after DW's movements were being tracked.
Dusek is merely trying to raise scenarios that would strectch out the time-frame in which the beetles started their activity back to 2/4-5. I really don't think his efforts will work. Feldman should have a very easy time getting the jury back on track, assuming the jury is even giving any credence to Dusek in the first place.