Sap by the fact that phloem sap is physiologically extreme in terms of animal digestion, and it is hypothesized that few animals take direct advantage of this because they lack two adaptations that are necessary to enable direct use by animals. These include the existence of a very high ratio of non-essential/essential amino acids in phloem sap for which these adapted Hemiptera insects contain symbiotic microorganisms which can then provide them with essential amino acids; and also insect "tolerance of the very high sugar content and osmotic pressure of phloem sap is promoted by their possession in the gut of sucrase-transglucosidase
Coccus hesperidum all the nutrients they need, the scale insects ingest large quantities of sap. They then secrete the excess sugary fluid as honeydew. This is attractive to ants which often tend the scale insects, driving away predators. The brown soft scale does not normally kill the host plant, but the loss of sap probably causes it to grow more slowly and crop less heavily. The main disadvantage to the host is the sooty mould which grows on the honeydew. This reduces the area of leaf available for photosynthesis, and spoils the appearance of the plant, its flowers and fruits. Traditionally, brown