Analysis Of Body Colour Variations And Main Energy Substance Contents Of Lygus Pratensis(L.)in Overwintering Period

The harm of Helicoverpa armigera Hubner has been effectively controlled by large area Bt cotton planting.Meanwhile,the use of broad-spectrum chemical pesticides reduced significantly in cotton,which leads to the dramatically increasing of the population of Lygus pratensis(L.).Lygus pratensis(L.)has become the main pest on the current Bt cotton in China.It has spreaded to a variety of other host plants.Recently,in the historical background of China’s cotton strategy westward,strengthening the study of mechanisms of outbreaks of Lygus pratensis(L.)is of great significance to ensure the safety of cotton production in Xinjiang.Nowdays,the research on Lygus pratensis(L.)is not sufficient,especially the study on overwintering and diapause behavior of Lygus pratensis(L.)adults.In this paper,the dynamic changes of biochemical matter in the body of overwintering Lygus pratensis(L.)was researched.A scientific reference for their comprehensive prevention and treatment was provided.Male and female adults in different periods were capturerd in order to observe their morphological changes via Leica stereomicroscope and measure the dynamic changes of biochemical matter contents in their bodies in different periods by spectrophotometry.The main research results are as follows:1.Body colour variations of Lygus pratensis(L.)adults in overwintering periodThere were obvious body colour variations for Lygus pratensis(L.)in overwintering period.the body colour variations from non-wintering to overwintering to late wintering are:yellow green,gray green,tan,brown red,grayish brown,respectively.Meanwhile,the colours of little triangle scutellum of Lygus pratensis(L.)adults also showed a series of changes of bright yellow to yellowish green to yellow with nonuniform blood-red to grayish yellow.There was a piece of dark spots gradually became larger in the central base.Besides,the colour of pronotum of Lygus pratensis(L.)adults showed obvious changes: callus light,orange yellow,grayish yellow,gray,dark gray,black,gray black.2.Analysis of main energy substance contents of Lygus pratensis(L.)adults in overwintering periodAfter measuring the dynamic changes of main energy substance of Lygus pratensis(L.)adults in overwintering period by spectrophotometry,it turned out that from non-wintering to early wintering to late wintering,body weight,total sugar content,glycogen content,fat content and trehalase specific activity of Lygus pratensis(L.)showed a trend of increasing first and decreasing later.The highest level in November were 0.0088 g,3.54%,15.25%,12.24% and 0.0077 OD ﹒ mg-1﹒ min-1respectively.However,water content and protein content showed an opposite trend and decreased to the lowest level between October and November which were 51.27% and 17.37mg﹒g-1 respectively.The above results showed that there was a certain relationship between the changes of main energy substance contents in Lygus pratensis(L.)and their cold tolerance.The changes of main energy substance contents were due to their ecological adaptation to winter light,food and temperature changes.It also showed that overwintering adults of Lygus pratensis(L.)reduced the level of metabolism to adapt to low temperature environment.Overall,this paper provided theoretical supports for the occurrence regularity and disaster mechanism of Lygus pratensis(L.).