PHYTOPHAGY
Plant-feeding sub-orders that are phytophagous within Hemiptera are:
The 'Stylet Ensheath' and 'Lacerate-and-flush' mouthpart is common amongst the herbivorous species of Hemiptera. Due to the form of the mouthpart is restricts the type of plants available for feeding resulting in a majority of the diet consisting of phloem sap from the stems and leaves of plants (Dolling 1991). Plant-feeders from the order Hemiptera prefer vascular plants, particularly angiosperms (flowering plants) as they lack a biting mandible restricting feeding to that of liquids (xylem fluid) and fine suspended particles that can be swallowed (Davies 1988). The stylets are surrounded by a sheath of solidified saliva which aids in the penetration of the plant (Dolling 1991). Formation of the salivary sheath is due to the salivary glands excreting the material where it lines the puncture through which the stylets are inserted (Schuh & Slater 1995). The 'Lacerate-and-flush' feeders macerate tissues by using their barbed apical portion of their mandibles followed by the mixing of saliva which is sucked up through the food canal (Schuh & Slater 1995). The food is passed along the food canal to the gut by contraction of a muscular cibarial pump where it passes the pharynx and enters the mid intestine (Davies 1988). Phytophagous Hemipterans are considered pests being responsible for some serious agricultural plant diseases and general plant destruction as seen in Figure 4 (Dolling 1991). |