I don't think insects are capable of trust or lack thereof in the sense you mean. They really just react. I've handled lots of spiders - if they sense they're being attacked/pursued, they will run/jump/bite/whatever. But remember how huge we are to them - we're more like landscape if we're not grabbing at them. If you move slowly and let them climb up, they don't think anything of it. So "trust" in that sense.