Minor addendum, weavels are not poisonous, you get them around the hot months, as their eggs hatch in rice. Most rice will contain some.
Before much more modern processes for rice production, there were always weavels after a while, because people bought much larger batches, stored for longer months, through larger humidity swings.
They just sort them out, or some don't bother and consider it extra protein. In rice eating cultures, weavels are considered (Clean) bugs.