Study On The Biological Characteristics And Cold-hardiness Of Locusta Migratoria Tibetensis

The Locusta migratoria tibetensis was described as a new subspecies in 1963.In recent years,it causes serious damage in Tibet, Yushu of Qinghai,plateau of western Sichuan. At persent ,most of the related reports were about its adult morphological characteristics and distribution, however,the morphological characteristics of egg and each instar nymph, biological characteristics,cold-hardiness have not been reported. In this thesis the morphological characteristics of egg and each instar nymph, biological characteristics and cold-hardiness have been studied systematically ,the results were as follows:1 The morphological characteristics of egg and each instar nymph. Its eggs were arranged slantly 4 lines in the columned colloid bursa, there were 40～107 eggs in each egg-bursa. The body color of each instar nymph of gregaria was black,black brown or dust-colour, while the body color of each instar nymph of solitaria was grass green or breen. Trough various analysis, the morphological indexes such as body-length, head-width, wing(bud)-length, back leg-length had reached significant difference among each instar nymph. In addition, each instar nymph and adult of gregaria were different in body-color,stripes,fleck.2 The living habit of the locusta migratoria tibetensis. The locusta migratoria tibetensis overwintered as egg in the soil. The hatched overwinter eggs began to feed after hatching 4～8 hours. They were fond of the fresh and tender lamina of gramineous plant. The nymph needed five ecdysises to be adult and each ecdysis lasted 30～60mins. The adult which liked high temperature and light as well as nymph were fond of feeding the lamina or culm of gramineous plant such as corn, pasturage. The female adult laid egg in the smooth, tight and condign humidity sand-soil.