Check the local firearms laws and the laws that pertain to defensive use of firearms. I don't know how Ecuadorian cops handle it, but if it were me, I would find out before getting into a shoot-out. I wouldn't want to be a guest of the state there.

If there is much banditry, you can assume they will be armed. Then you have to make an informed choice. If they usually leave victims poorer but unharmed, consider choice between writing off your stuff and getting in a gun fight with folks that probably have more practice at it than you do.

If you can carry a firearm legally and decide you need one and can use one competently when under fire, the better choice would be a repeating shotgun - the smaller and lighter the better - even a single or double-barreled shotgun. Any shotgun is intimidating - with good reason. The next choice would be a small, light rifle with a mild cartridge - anything from 9mm through 7.62X39 to 30-30. Even a pipsqueak cartridge is adequate when facing folks who want to live to rob another day. Rifles are more accurate under difficult conditions and safer for the user than pistols. A handgun is barely adequate for anything except clubbing folks at close range or saving the last bullet for yourself, but it might have some deterrant value. Again, most bandits are not going to risk their lives over whatever paultry plunder you might be hauling in a backpack. But if it comes to shooting, a shotgun would be my choice by far.