Posted: 17/05/2016 at 12:13
It is up to you Mynx.
If they bother you there are controls...but spraying now and then with water helps deter them. I control woodlice, ants around the home but leave them be in fhe garden. Often ants are a pain on plants by farming aphids so a control is by spraying for aphids.
I would put the rock back and not worry about them.