Looks like spider webs. As predators, their relationship to the dead spots in the lawn would only be to exploit the opportunity to easily build a web over them, and/or to hunt/trap small critters attracted to (or hatching from) the bare spots.
The last pic looks like chunks of dead grass were left in the lawn after mowing? That can make dead spots. If that's what happened, you can rake the cut grass around a bit so it's not so thick in any 1 spot to avoid that in the future. Try not to mow when grass is damp, so it doesn't clump up so badly.
