草地螟幼虫取食量、头宽、体长及体重的测定

研究了草地螟(Loxostege sticticalis L.)幼虫的取食量、头宽、体长及体重增长的变化。草地螟的幼虫历期约为13 d，取食量635 mg，其中前3龄的取食量仅为幼虫总取食量的30%，而4、5龄的取食量分别占24%和46%。幼虫头宽增加的数值从1龄的0.31 mm增加到5龄的1.51 mm，增加的数值随幼虫龄期的增加而增大，增加倍数则随龄期的增加而缩小。幼虫体长从1龄的2.3 mm增加到5龄的18.9 mm，增加了约7倍。体重则由1龄期的0.2 mg增加到5龄时的43.6 mg，增加了约240倍。3龄前幼虫体重增长缓慢，4龄后增长量达到10 mg以上，到5龄第2天达到最大值68.94mg后下降。幼虫的总取食量约为本身体重的15倍。本文还讨论了以上结果在了解草地螟幼虫危害特征和规律及监测、防治中的作用。

Determination of food consumption, head width, body length, and body weight of the larvae of the meadow moth, Loxostege sticticalis

Food consumption,head width,body length and body weight of the larvae of the meadow moth,Loxostege sticticalis L.,were investigated.The results showed that its total food consumption was 635mg during larval development period.The 1st,2nd and 3rd instars accounted for 30% of the total,while the 4th and 5th instars accounted for 24% and 46%,respectively.The head width increased from 0.31 mm(1st instar)to 1.51 mm(5th instar),and the later the larval instar,the more the head width increased,but the increase multiple decreased with larval development.Body length and weight of the 5th instars increased by about 7 times and 240 times,respectively,compared with that of the 1st instars.Before the 3rd instar stadium,body weight increased slowly,but from the 4th instar it increased rapidly to reach the maximum of 68.94 mg on day 2 of the 5th instar,and then declined,accounting for one fifteenth of the total food consumption.