score:1
Surely, the suttas, aimed towards forest-dwellers, must have some guidelines on harmful insects and animals
Yes: there is a sutta in which the Buddha tells forest-dwelling monks to practice a mind of good-will towards other beings -- see Ahina Sutta: By a Snake.
Perhaps if you were practising good-will you might be careful not to stand on or disturb them.
Upvote:2
This is not justifiable in terms of the precepts. Also any action like killing will be rooted in hatred, hence is counter-productive to achieve the Buddhist goal of Nirvana or peace for one self. Also you have to look at the possible effect on subject of the action. Will the subject be happy about it.