Glyphosate is the only active ingredient in Round Up. I am not aware of Round Up ever being detrimental to spiders and insects. But,,, Sometimes all it takes is over hearing your neighbor saying he heard that his cousins friends uncle's brothers co-workers friend sprayed Round Up and all the Spiders died. Then possibly some environmentalists may right documentation on this fact on their website and push for its mass banning across a Country. This might be the reason it is not used in France? I am just kidding! I wasn't aware it was not to be used in France. Won't be long and it will be banned here in BC too.