A normal 17 yr old. who gets bitten by black widow or brown recluse spider. does he require treatment?

Find out which one: It's important to find out which one as they require very different treatments. Black widows have a neurotoxic venom that can attack the respiratory system. Brown recluse (fiddle-back or violin spiders) have a hemotoxic venom that causes necrosis and ulcer formation. Both require treatment. See your doc right away.

Spider bites: In my opinion "Yes". Both bites can lead to trouble. He should seek medical attention immediately. Hope this helps.