Both the spiderlings and large spiders are casting weak poison. It's a 6HP per tick dot for 1 min. Spiderlings should not be casting any poison.
Large spiders should be casting Feeble Poison.
Link to Weak Poison
http://everquest.allakhazam.com/db/s...tml?spell=1001
Link to Feeble Poison
http://everquest.allakhazam.com/db/s...tml?spell=1000
I'd check to see what poisons the snakes are casting too. I haven't really messed with the snakes, but moss snakes should have feeble and tree snakes should have weak.