The original Compound Interest article on insect venom and the Schmidt pain index can be found here. Please look at the graphics and read the article.
You can listen to an interview with Schmidt who developed the pain scale here (it is the first ten minutes) on a RadioLab podcast (I highly recommend their shows).
What's the difference between poison and venom? There's a TedEd Talk on that! Watch it HERE.
How does your brain respond to pain? There's a TedEd Talk on that! Watch it HERE!
Want to know more about ant colonies? There's a TED talk on it. Watch it here.