不同食料对黄地老虎生长发育和繁殖的影响

幼虫在不同食料饲养中,以灰藜最好,苘麻最差。前者幼虫期平均23～30.9天,脱皮4～5次,自然死亡率4.3～8.0％;后者则各为46.1～47.1天、6～7次、45％。各种食料饲养的蛹重,以白菜和灰藜较重,马铃薯较轻。蛹重不是决定成虫产卵高低的主要因子,而与幼虫取食食料种类关系较为密切。如幼虫取食白菜、棉花及玉米、马铃薯混杂草者,较取食旋花、马铃薯及玉米者产卵量高0.15～2.23倍,产卵期和寿命亦较长。取食混合食料的幼虫,发育速度和成虫产卵量,一般均较取食单纯一种食料为高。在成虫取食各种花蜜饲养中,以供食蜂蜜红糖水、马蔺花和向日葵花者产卵率和产卵量最高,白菜花、苜蓿花和清水者最低,前者为后者产卵量的1.99～14.06倍,雌蛾产卵率高11.1～35.7％,产卵期和寿命亦以前者为长。从幼虫和成虫取食不同营养对产卵量的对比来看,成虫期补充营养较幼虫期营养更为重要。因而某一地区蜜源植物的种类、分布密度以及蜜源植物花期与成虫发生期的符合程度,是决定某地区黄地老虎种群密度高低、为害轻重的最主要因素之一。

INFLUENCE OF VARIOUS FOOD PLANTS ON THE GROWTH AND FECUNDITY OF AGROTIS SEGETUM

Various food plants were tested to the larvae and moths of Agrotis segetum (Schiff.) to see their influence on the number of eggs laid.The results show that when larvae fed on leaves of Chinese cabbage,cotton,corn,along with some wild herbs,the moths emerged laid more eggs and lived longer than those from the larvae fed on other plants.Thelarval stage of those fed on Chenopodium spp.is much shorter than thoseon Abutilon spp.and the percentage of mortality is also lower.Moreover,body weights of the pupae whose larvae fed on Chinese cabbage or Chenopodium are heavier than those on potato. Results showed that the moths laid more eggs (1.99~14.06 times)when feeding on honey and suger,nectar of Aster or Helianthus flowers than living on Chinese cabbage or alfalfa flowers or water alone. It seems that supplementary diet taken at adult stage has a more imoportant effect on fecundity than the quality of foodstuff taken at larval stage.