Some insects are only found in the specific area, so finding these insects on the crime scene will find out at what stage the body is and give some indication on how long the body is dead.
Some of the insects are found at daytime and some are found at night time so seeing these insects provides the evidence that the crime happened at day or night time.
The stage of the insects body also helps in determining the stage of body.
Natural selection is when the organisms that have the better adaptation so they survive. In this case, the green was the better adaptation so they lived.
