Hemiptera plant. Phloem sap, which has a higher concentration of sugars and nitrogen, is under positive pressure unlike the more dilute xylem sap. Most of the Sternorrhyncha and a number of Auchenorrhynchan groups feed on phloem. Phloem feeding is common in the Fulgoromorpha, most Cicadellidae and in the Heteroptera. The Typhlocybine Cicadellids specialize in feeding on non-vascular mesophyll tissue of leaves, which is more nutritious than the leaf epidermis. Most Heteroptera also feed on mesophyll tissue where they are more likely to encounter defensive secondary plant metabolites which often leads to the evolution of host specificity. Obligate xylem feeding is a
Tonlé Sap gods. This also marks the end of the rainy season. The area is home to many ethnic Vietnamese and numerous Cham communities, living in floating villages around the lake. Approximately 1.2 million people living in the greater Tonle sap make their living by fishing on the local waters. Cambodia produces about 400,000 tonnes of freshwater fish per year, the majority of which comes from Tonle sap. These fisheries account for 16 percent of national GDP, making the fish industry not only essential to the diet of local populations but to the Cambodian economy as a whole. Tonlé Sap Tonlé Sap