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 the Khmer Rouge took over from 1975 to 1979. We had to flee to Vietnam, [but] afterwards we came back and have been fishing on the Tonlé Sap ever since." Thousands of peasants follow this lifestyle. Catching Tonle Sap fish is simple. Later, the real work begins. Because of the drop in the water level, the Tonlé Sap naturally carries away thousands of fish. Fishers place cone-shaped nets into the water from their floating houses and then lift the net as soon as seconds later. Using this technique, two or three tons of fish are trapped each time and more