桑螟越冬幼虫体内水分、脂肪、甘油的变化与抗寒性的关系

为预测桑螟的虫口密度及种群变化,研究了桑螟越冬幼虫体内水分、脂肪、甘油与抗寒性的关系。越冬幼虫体内含水量随气温下降逐渐减少,过冷却能力随体内水分的减少而增强,越冬后期随水分的增加而降低;越冬幼虫过冷却点的变化与体内结合脂肪的含量变化呈正相关,即过冷却能力随结合脂肪含量的升高而增强,降低而减弱;从越冬初期进入越冬期后,幼虫体内甘油含量逐渐增加,1月份增加幅度最大为1810%,越冬后期随温度升高,体内甘油含量下降。过冷却点的变化随甘油含量的不断增加而逐渐降低,12月和翌年1、2月,甘油含量最高,分别为972、1082、887mg/mL,其过冷却点也降至最低,分别为-1838、-1888和-1969℃;3、4月甘油含量逐渐减少,过冷却点随之升高。

Relation Between Variation of Water, Fat, Glycerol in vivo of Over-wintering Diaphania pyloalis Walker Larvae and Cold-hardiness

In order to forecast density and population change of Diaphania pyloalis walker,relation of water, fat and glycerol in vivo of over-wintering Diaphania pyloalis Walker larvae and cold-hardiness was studied. The results showed that water content in vivo decreased along with air temperature declining,and the super cooling capability enhanced along with water content in vivo decreasing, reduced along with water content in vivo increasing, that correlation between variations of the super cooling point and combined fat content in vivo were positive, that glycerol content increased gradually during the over-wintering period, decreased along with temperature rising after the over-wintering period, that glycerin content reached the peak level which was 9.72, 10.82 and 8.87 ~mg/mL in December, January and Feburary in the next year, respectively, whereas the supper cooling point was the lowest which was-18.38,-18.88 and-19.69 ℃ respectively, and that the supper cooling point increased along with glycerin content decreasing gradually in March and April.