挂卵密度对豆天蛾幼虫生长发育和大豆产量的影响

Effects of hanging density of Clanis bilineata eggs on the larval growth and development of this species and on soybean production

【目的】通过比较豆天蛾Clanis bilineata Walker卵在不同密度下对幼虫生长发育和大豆产量的影响,筛选大豆种植密度一定时的最佳挂卵密度。【方法】选择大豆种植密度为行距×株距=40 cm×20 cm的田块,选取面积为20 m~2的小区9块,将挂卵密度为10、20、30、40、50、60、70和80粒/m^(2)的卵粒分别挂在小区内,以不挂卵小区作为对照,每个处理分别设置3次重复。统计不同挂卵密度的豆天蛾幼虫在收获时幼虫生长日龄、存活率、体长、体重、幼虫产量和大豆产量等指标。【结果】挂卵密度为30粒/m^(2)幼虫在25日龄被收获,且幼虫存活率达到最大值,为58.44%,其次是挂卵密度为10、20和40粒/m^(2),幼虫存活率分别为58.33%、55.56%和52.33%,4个处理间幼虫存活率差异不显著(P>0.05),但均显著高于其它4个处理(P<0.05);挂卵密度为30粒/m^(2)的幼虫体长与挂卵密度为10粒/m^(2)的幼虫体长相同,均为8.09cm,且高于其它6个处理;挂卵密度为30粒/m^(2)的幼虫体重为9.35g,仅小于挂卵密度为20粒/m^(2)的幼虫体重(9.39 g),但二者的幼虫体重无显著性差异(P>0.05);挂卵密度为30粒/m^(2)的幼虫产量高达158.00 g/m^(2),其次分别为处理40粒/m^(2)和50粒/m^(2),幼虫产量分别为153.00 g/m^(2)和140.17 g/m^(2),3个处理的幼虫产量间无显著性差异(P>0.05),但均显著高于其他5个处理(P<0.05);卵密度为30粒/m^(2)时大豆产量为142.50 g/m^(2),显著低于对照大豆产量210.33 g/m^(2)(P<0.05)。【结论】在30粒/m^(2)挂卵密度下,豆天蛾幼虫各项指标表现良好,符合市场发展需求。此结果为豆天蛾人工养殖提供了一定的理论基础和技术指导。

[Objectives]To compare the effects of different hanging densities of Clanis bilineata eggs on larval development and soybean production in order to determine the optimal hanging egg density for the artificial propagation of this species.[Methods]At a soybean planting density of 40 cm×20 cm(row spacing×plant spacing),the egg hanging density was experimentally set at 10,20,30,40,50,60,70 or 80 eggs/m^(2).Eggs were hung in 20 m~2 plots with 3 replicate plots for each of the 8 treatments,plus a control plot without eggs.The developmental period,survival rate,body length,body weight and total yield of larvae and soybeans,were compared between treatments and the control.[Results]Larvae were harvested at 25 days of age.The highest larval survival rate of 58.44%was recorded at a density of 30 eggs/m^(2),followed by egg densities of 10,20and 40 eggs/m^(2)(58.33%,55.56%and 52.33%,respectively).Although there was no significant difference in larval survival rate of these four treatments(P>0.05),they were collectively significantly higher than those of the other four treatments(P<0.05).The body length of larvae in the 30 eggs/m^(2)group was the same as that of larvae in the 10 eggs/m^(2)group(8.09 cm),and were collectively higher than those in the other 6 treatments.The body weight of larvae in the 30 eggs/m^(2)group was 9.35 g,although less than that in the 20 eggs/m^(2)(9.39 g)group,was not significantly different(P>0.05).The highest larval yield of up to 158.00 g/m^(2)was recorded in the 30 eggs/m^(2)group,followed by the 40 and 50 eggs/m^(2)groups which had larval yields were 153.00 and 140.17 g/m^(2),respectively.There was no significant difference in larval yield among these three treatments(P>0.05),but they were collectively significantly higher than those of the other five treatments(P<0.05).The soybean yield was 142.50 g/m^(2),significantly lower than the control group yield of 210.33 g/m^(2)(P<0.05).[Conclusion]Larvae performed well at a density of 30 eggs/m^(2),which is consistent with the market demand.The results provide a theoretical basis and technical guidance for the artificial culture of Clanis bilineata.