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Spodoptera litura Fabricius Spodoptera litura is a worldwide distribution of more fresh outbreaks of pests, a hazard 99 families, 209 species of plants, significantly increased outbreak frequency in recent years, outbreaks of the area has expanded each year, worsening damage caused serious losses to agricultural production . The Spodoptera litura fecundity strong fecundity vulnerable to outbreaks in a short period of time up to about one thousand. Host plants affect of Spodoptera litura fecundity important influencing factors. Host plants on the fecundity of Spodoptera litura in the final analysis is the development of their internal reproductive organs by affecting their hormone regulation, and also directly affects the soluble protein synthesis changes in their reproductive system. Therefore, in-depth study of different host plants on the fecundity of Spodoptera litura its mechanism to clarify the the Spodoptera litura outbreaks hazards inherent mechanism has important theoretical and practical significance. The extent of the test according to the preference of Spodoptera litura indoor feeding on different host plants (cabbage, cotton, potato, soybean, cowpea, Agasicles grass) were observed, studied feeding on different host plants, Spodoptera litura growth and fertility, the female and male reproductive system development, genital changes in soluble protein content as well as the different developmental stages of S. litura vivo ecdysone and juvenile hormone changes. The experiments on different host plant leaves nutrients, and the different mechanisms of host plants on the fecundity of Spodoptera litura. The main conclusions are as follows: 1. The fecundity impact of different host plants on Spodoptera litura significantly, and fecundity of different host plants on Spodoptera litura potential fecundity (potential fecundity = actual fecundity of intra-abdominal residual broadly consistent the egg amount) and the output rate trend. This experimental study showed that the the Spodoptera litura feeding on different host plants, the actual fecundity and the potential fecundity order are: cabbage gt; Cotton gt; potato gt; soybean gt; cowpea gt; hollow Alternanthera. Cabbage is one of the host plants of S. litura like eating, the Spodoptera litura feeding cabbage is also the largest of its fertility, the actual fecundity potential fecundity and output rate are respectively 1561.23 / head 1596.08 / head and 97.50%; while intra-abdominal residual the egg amount but at least an average of only 34.85 / head. Alternanthera philoxeroides twill the armyworm not eating host plants, feeding on of Alternanthera philoxeroides the twill armyworm fecundity minimum, actual fecundity, potential fecundity and output rates are the smallest, respectively, 537.57 grain / head, 692.08 / head and 77.48%; intra-abdominal residual egg is the largest, with an average of only 156.50 / head. The Spodoptera litura feeding on cabbage, its actual spawning about feeding Alternanthera philoxeroides 3 times, a potential spawning about feeding of Alternanthera philoxeroides the 2.3 times. This shows that feeding eating the host plant, the fecundity of Spodoptera litura generally relatively strong. 2 genitals of different host plants on Spodoptera litura significant influence growth and development. After feeding on different host plants, Spodoptera litura ovarian tubes, 1-day-old male and a 3-day-old unmated male on male reproductive accessory gland length and fresh material small testis fresh major trend is basically the same, the order as: cabbage gt; Cotton gt; potato gt; soybean gt; cowpea gt; Alternanthera philoxeroides. This study found that feeding than eating the host plant cabbage, cotton, potato, Spodoptera litura reproductive development, and this has important implications for the size of its fertility. Different host plants of the Spodoptera litura reproductive system development corresponding to different host plants of the Spodoptera litura reproductive system soluble protein synthesis also exists a significant impact. This study were 1-day-old, 3-day-old, three different stages of the 3-day-old Spodoptera litura after pairing, the size of the content of soluble protein in their reproductive organs. Found feeding on host plants than eating cabbage, cotton, potato, Spodoptera litura reproductive organs soluble protein content; while feeding on soybean, cowpea, Spodoptera litura Alternanthera philoxeroides, their reproductive organs soluble protein content relative low. This test by HPLC ecdysone and juvenile hormone JH Ⅱ on the the Spodoptera litura body of different developmental stages were determined. Found soybeans and cotton twill armyworm feeding, mature larvae ecdysone levels significantly higher than those fed on other host plants of S. litura; litura, mature larvae feeding on cabbage ecdysone content minimum. Of Spodoptera litura emergence of adults, their in vivo ecdysone content decreases rapidly, and have been unable to detect the use of this test method. Juvenile hormone synthesis of different host plants on Spodoptera litura old mature larvae and adult female body has a significant impact. The Spodoptera litura feeding on cabbage and cotton, the mature larvae in vivo juvenile hormone content significantly higher than those feeding on other host plants. After the emergence of Spodoptera litura adult, juvenile hormone content of the female body dropped significantly. 1-day-old and 3-day-old the Spodoptera litura adult female body, feeding on cabbage and cotton JH Ⅱ contained significantly higher than those feeding on other host plants; feeding Alternanthera philoxeroides and cowpea of ??Spodoptera litura adult female body contained JH Ⅱ significantly lower. Feeding on different host plants, 1-day-old, 3-day-old the Spodoptera litura adult male body juvenile hormone JH Ⅱ content trends. The Spodoptera litura feeding on cabbage, cotton and potato JH Ⅱ contained significantly higher, while feeding on Alternanthera philoxeroides and cowpea Spodoptera litura JH Ⅱ contained lower. Nutrients content in the different host plant leaves relative water content, soluble sugar content, total nitrogen content was significantly different. The Spodoptera litura than eating the host plant cabbage, the cotton three major nutrients content higher, significantly higher than the other host plants. . Fecundity impact factor, the test sub-factors, reproductive factors as the mother of factors influencing factors and reproductive factors fecundity gray correlation analysis to find out the relationship between them. Of gray relational analysis, the Spodoptera litura body JH Ⅱ, host plant leaves soluble sugar content and nitrogen content of actual fecundity of Spodoptera litura, potential fecundity, the output rate and pupal weight are closely related contained. The research showed that the and, JH Ⅱ, soluble sugar and nitrogen content of the host plant is the to affect the Spodoptera litura fecundity main factors. The Spodoptera litura body ecdysone contained in leaf water content less fecundity of Spodoptera litura. Experimental study, we can speculate that different host plants on Spodoptera litura reproductive impact may be accomplished through the following means: because the nutrients contained in different host plants, different soluble sugar and nitrogen, Spodoptera litura take food on different host plants, its body ecdysone and juvenile hormone content differences affecting the the Spodoptera litura reproductive system development and its soluble protein synthesis, eventually leading to its fertility differences.
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