Why? Are you arguing that insects are purely automatons? I personally don't have a strong view on insects, but my intuition is that there are different degrees of consciousness, and feel natural to attribute some consciousness to insects, and even individual amoebas, and maybe even (as in Chalmers's famous example) to thermostats.

I would draw a separate line around sapience, and particularly the capacity for suffering, maybe indeed attributing it to mammals and birds but not insects, but consciousness seems more widespread to me.