In a world I'm creating, a group of humans from Stone-age earth have been shrunk to 2 centimeters tall and are now stranded in another Earth-like world similar to our own, but without vertebrates. Arthropods and plants are now the main domination of this world. The insects, however, are very similar to our own, but just appear a lot larger than a normal person. As for the square-cube side effects concerning on the humans, it's all handwaved. Other than that, they gotta be careful of fire and heat due to its high radiation.
The problem with these humans is that the place they were transported to is nothing but miles of tall grass blades and hills. After a day of exploring this strange environment, they encountered holes that contain nests of bumblebees and yellowjackets. They also found many different diverse species of beetles, some reaching 10 cm long.
The humans are considering taking down these large beasts for their exoskeletons and for food since there are no signs of trees or wood to come around. The gatherers considered gathering blades of grass and roots, tying them up to sturdy materials to take down the giants, just like their Recebr Ancestors did on the mammoths back in the ice age.
So are grass blades and roots strong enough for these tiny humans to be viable as materials to construct blades and maces to chop the legs and pierce the exoskeleton of these beetles? Or would there be alternate methods in this great plains like environment for the humans to use to take out these beetles?
As for the type of grass, it doesn't matter too much on the kind of grass used, just as long as this grass is well suited to a great plains environment.