Does glyphosate poison insects at all? It targets a pathway specific to plants, and generally is non-toxic to everything else.

Farmers (and gardeners and homeowners) use a whole lot of other pesticides to kill insects, which will affect non-targeted species. Slug baits sometimes are mixed with other broad-spectrum insectisides, and Raid is persistent (part of it's design is to kill the wasps that return to the nest later!)

Roundup is glyphosate plus a surfactant. The surfactant is use to strip the waxy coating on plant leaves so the glyphosate can act. I've read the surfactant is the bigger issue for insects.