Effects of Interspecific Competition on the Population Dynamics of Four Stored Grain Insect Pests

The effects of interspecific competition on the population dynamics of four insect grain Insecp pests （ Sitophilus zeamais, Rhizopertha dominica, Tribolium castaneum and Cryptolestes ferrugineus ） was studied at 30℃, 75% relative humidity. A regression analysis of the population dynamics was conducted. The results showed that population growth of S. zeamais , R. dominica, T. castaneum and C. ferrugineus was restrained under mixed rearing. Population growth of T. castaneum and C. ferrugineus was remarkably accelerated when they coexisted with S. zeamais or R. dominica, while that of S. zeamais and R. dominica was restrained to some extent. Regression analysis results showed that the population growth potential of S. zeamais was the largest and that of C. ferrugineus was the smallest, and the changing trends of population growth rates were not distinct.

糙米与被锈赤扁谷盗侵染糙米挥发性化合物对比分析

以黑龙江地区糙米(绥粳18)为研究对象,研究储藏期内锈赤扁谷盗(Cryptolestes ferrugineus(Stephens))侵染后糙米挥发性化合物的变化特点,意图寻找锈赤扁谷盗侵染后糙米中变化最为显著的挥发性成分。通过2种固相微萃取模式(顶空固相微萃取,HS-SPME;浸入固相微萃取,DI-SPME)结合气相色谱-质谱联用(GC-MS)技术,对锈赤扁谷盗侵染后糙米挥发性成分进行提取分析。结果表明:糙米被锈赤扁谷盗侵染后挥发性成分含量整体上升,酸类物质的变化最为明显;通过主成分分析、正交偏最小二乘判别分析等多元统计分析方法筛选出被锈赤扁谷盗侵染后糙米中变化最为显著(P<0.05,VIP>1,∣LOG2(Fold Change)∣>0.5)的7种挥发性成分,分别为γ-亚麻酸、(E)-角鲨烯、(Z)-11-十八碳烯酸、1,15-十六碳二烯、9-辛基-十七烷、正三十一烷和正十四碳酸,这些化合物的发现有助于从代谢水平了解有害生物对糙米产生的影响。