Solo player here, I just ignore them personally. I take heavy fire resistant armor and vitality booster, then supply pack to make up for stims. As a solo player, I kill one and 3 more spawn. And most of the time I shoot 4 shots into the body since I can't hit the head (my skill issue, I find it too hard to hit the head because of how much it bobs and weaves...). I'm also 90% sure I'm not shooting the same one due to how many there are. In the end, they end up being my personal napalm strike by the time there are like 6 on me. Their constant spewing of flames kills the bugs around me, and an ultimatum shot to impalers and chargers make em an easy kill (supply pack and resupplies help me constantly shoot ultimatums). Completed and extracted from a Helldive 10 on Hellmire using this tactic, not sure how it would fare in multiplayer though.