The following is a list of the most important items to pack. 

• Main Backpack with capacity of 4500 centiliters
• Smaller Daypack for quick trips in the city or jungle
• Nylon swimshorts – for quick drying during jungle treks
• LED Headlamp lasts 80 hours on one set of batteries.
• Luxury item – High power 6 volt flashlight to see nocturnal creatures 

You might want to bring your own hammock, mosquito net, or sleeping bag but if you are trying to save weight like I normally do you can usually rely on using the supplies for a tour agency.  Remember it´s more important ot have money than stuff and more important to have time than money!