水浸对小菜蛾卵和蛹的影响

Effects on The Egg and Pupa of Diamondback Moth Plutella xylostella Immersed in Water

通过研究小菜蛾卵及蛹经水浸后存活和生殖情况,了解降雨产生的积水对小菜蛾种群的影响。将小菜蛾在25℃环境中1h内所产的卵在25℃发育0h、24h后,分别用无菌水浸泡24h、48h,处理后除去无菌水,在25℃观察卵的孵化情况;将在25℃环境中化蛹时间为24h内的小菜蛾蛹,用无菌水浸泡24h、48h,处理后除去无菌水,在25℃观察蛹的羽化率及羽化成虫的生殖力。在25℃发育0h小菜蛾卵经24h、48h浸泡后,孵化率没有显著下降,但25℃发育24h浸泡48h后,孵化率显著下降;卵在水中可以正常发育;蛹经水浸处理后羽化率显著下降,生殖力显著下降;但各处理羽化率仍然高于50%,生殖力最多下降38.8%。短期(≤48h)水浸不会造成小菜蛾卵和蛹灭绝性死亡,降雨积水可能不是夏季田间小菜蛾种群绝迹的主要原因。

In this study,effects of immersion in water on egg and pupa of diamondback moth Plutella xylostella were investigated to understand the effects of accumulation water of rainfall on the population dynamic of diamondback moth in the field.The Oh and 24 h development time eggs which were produced in lh in 251 were immersed in distilled water for 24 h or 48 h,then they were moved to the normal condition and the hatching eggs were recorded everyday.The 24 h development time pupae were immersed in distilled water for 24 h or 48 h,and the adults emerged were recorded everyday.When the adults emerged,one female and one male were closed in one Petri dish,A piece of fresh cabbage leaf was provided for egg laying.The eggs produced were recorded everyday until the death of the adults.The hatching rates were not significantly decreased after immersion in water for 24 h or 48 h while the 24 h development eggs’hatching rate was significantly decreased when immersion time was 48 h.The eclosion rates and fecundity were significantly decreased for 24 h or 48 h immersion time,but the eclosion rates were still higher than 50%,fecundity were only decreased by 38.8%for 48 h immersion time.Short time(≤48h)immersion can not lead die out of egg and pupa of diamondback,the accumulation water of rainfall may be not the key reason for the die out of the diamondback moth in the filed in summer.