If you're referring to the spider which appears several times throughout the intro - and not the tarantula, which only appears once - it appears to be a species of Golden Orb Weaver, sometimes called a Giant Wood Spider.
This genus of spiders is very common throughout the world, typically found in warmer climates - the Southern US, Asia, Africa, and Australia. They are mostly harmless, with a moderate bite and non-aggressive temperament. They are known, however, for their creepy appearance and extravagant webs. They can also grow quite large, with a body of over 2 inches (excluding legs).
The spider does not appear to have any direct connection to the content of the show, and is most likely used in the intro to establish atmosphere.