Apart from the indirect effect (killing flowering plants means less food for insects) there seem to be direct effects as well e.g. https://www.ncbi.nlm.nih.gov/

Apart from the indirect effect (killing flowering plants means less food for insects) there seem to be direct effects as well e.g. https://www.ncbi.nlm.nih.gov/pubmed/25063858/ https://www.ncbi.nlm.nih.gov/pubmed/25063858/