The Study On Mouthpart Structure,Digestive Enzymes And Food Selection Of Grasshopper

From Morphological structure of grasshoppers'mouthpart, midgut, salivary glands, interrelated Enzyme Activity of digestive enzyme and their food plants etc., researches were done on the grasshoppers'food selection, which do not only provide gist for insect morphology and insect classification, but also compare the grasshoppers'morphological structure, the adaptation of their mouthparts, insect physiolopy, pest control and annihilate.The microstructure of oriental migratory locusts'mouthpart and cibarium were studied by optical microscope and scanning electron microscope. New subarea and denomination of oriental migratory locust's labrum have been conducted. The clypeus of oriental migratory locust's labrum is composed of praeclypeus in the middle of which, central convexity praeclypeus is located and postclypeus. Labrum and clypeus are linked together. The ossification outward is outer lip, in the center of which there is central convexity labralis, on both sides of which it is back-convexity labralis. While the fore-convexity labralis is under the fossa labralis transversalis. In the middle of the lower end of the fore-convexity labralis, there is a concave called fore-concave labralis. The epipharynx of the oriental migratory locust is divided into central area, peripheral within the area, peripheral area and marginal area. The pharynx of the Locusta migratoria manilensis includes ten parts: posthypopharynx, two basal mandibles, two basal clypeus, central section of clypeus, two clypeus sensory areas and two irregular-vesicle areas.Through optical microscope and scanning electron microscope, it has been found that seven types of sensillum are densely distributed in oriental migratory locust's labrum and pharynx:sensillum trichodeum, sensillum basiconicum, sensillum chaeticum, sensillum campaniformium, sensillum coeloconicum, sensillum finestra and sensillum irregular-vesicle area, and conjecture the functional of these sensillum.According to the measurement of the activities of digestive enzyme in Locusta migratoria manilensi's midguts and salivary glands by spectrophotography, it can be concluded that first, there are no significant discrepancy between cellulose activities in Locusta migratoria manilensi's midguts and salivary glands; second, the salivary glands play a very important role in the course of their digestion of cellulose; third, no lipase exists in their salivary glands and midguts. However, the amylase activity is high in Locusta migratoria manilensis' midgut, and there are significant discrepancies between the amylase activity in midguts and salivary glands, which show that midgut is the main organ to digest amylase with salivary glands only playing an additional role. To Locusta migratoria manilensi, the protease activities in midguts are all statistically significantly higher than ones in salivary glands, which illustrate that their digestion of albumen all depend on midgut. Compared with the maltase activities in its midguts, the maltase activities in its salivary glands are obviously higher, which indicates that salivary glands are the main digestive organ to Locusta migratoria manilensis. The pectinase activities in its midguts are greatly higher than the ones in their salivary glands, which improves that midguts are the main organ responsible to digest pectin. According to the result of these enzymes activity,we determined the eating plants species of Locusta migratoria manilensis.Through two years'field observation,since 2007 document retrieval and analysis,70 kinds of plants and 52 grasshopper food plants have been gathered and identified and a key of grasshopper food plants has been drawn up.