棉铃虫幼虫感染白僵菌后呼吸速率和食物利用效率的变化

研究了球孢白僵菌Beauveria bassiana侵染棉铃虫对3龄幼虫呼吸速率和食物利用的影响。结果表明,1×10~6和1×10~8分生孢子/ml孢子悬浮液处理后,高浓度处理幼虫前3d的呼吸速率较对照下降幅度缓慢,但从第4d起呼吸速率明显下降。低浓度组在处理后的前2d呼吸速率上升,随后逐渐下降。总体上,白僵菌侵染后棉铃虫幼虫的呼吸强度较对照呈先显著上升后迅速下降的趋势变化。处理后1～2d棉铃虫幼虫的取食量、体重增加数及食物转化率(ECD)、利用率(ECI)等各项营养指标与对照无显著差异,但3～4d后棉铃虫取食减少,体重下降,食物利用率ECI和转化率ECD出现负值,并逐渐死亡。

THE CHANGES OF THE RESPIRATORY RATE AND NUTRITION UTILIZATION EFFICIENCY OF HELICOVERPA ARMGERA (HÜBNER) INFECTED BY BEAUVERIA BASSIANA

The physiological changes of Helicauerpa armigera(Hübner) infected by Beauveria bassiana were investigated in the laboratory. The results showed that the respiratory rate of the larvae, which was in high (1×10⁸conidial/ml) concentration treatment, decreased slowly in the first 3 days compared with the control, however, it decreased drastically from the 4th day. For the low (1×10⁶conidial/ml) treatment, the respiratory rate increased in the first 2 days, then decreased gradually. In general, the larvae of cotton bollworm tended to speed up respiration firstly and then decreased in the course of infection. As for the food consumption, weight gain, fecal production and nutrition indexes such as net efficiency (ECD), gross efficiency (ECI), no significant difference was found between the 2 treatments and the control in the first 2 days, but there was significant difference along with the penetration of the integument by growing hyphae.