No, it's a mod of Warcraft III, the Frozen Throne - a computer game. It stands for Defense of the Ancients. It's similar to a game of capture the flag, though instead of capturing the flag, you're destroying it, and instead of putting your opponents in jail, you're slaughtering them. Over and over and over.
In other words, pretty typical computer game fare.
Dendrobates is the genus name for several of the many varieties of poison arrow tree frogs in the world. I chose this screenname when I was a science teacher a few years back. "Dendrobatida" has nothing to do with DOTA, but nice letter pattern recognition.