【目的】为探讨昆虫嗅觉感受机理及其化学感受行为机制提供技术基础。【方法】对家蚕Bombyx mori雄蛾触角部分切除后,测定其触角电位(EAG)变化;构建家蚕雄蛾并联等效电路模型;分析EAG与电路模拟器件间的关系。【结果】切除部分分枝后,EAG幅值与整根触角相比,除保留中部10个分枝的处理组无显著差别外,其余6组均显著减小;噪声强度有随触角分枝数量减少而增加的趋势;信噪比(SNR)有随分枝数量减少而减小的趋势;触角中部分枝数量由10个逐渐减少时,其EAG幅值随之线性减小。切除尖部主干后,EAG幅值增加,噪声强度减小,SNR增强;切除基部主干后,EAG幅值减小,噪声强度增加,SNR减弱。构建获得了基于触角主干和分枝阻抗的EAG并联等效电路模型,能较好地模拟实验测定结果。【结论】触角主干和分枝的阻抗对EAG信号输出有较大影响,EAG并联等效模型经具体化和改进后可适用于其他类型昆虫触角的EAG实验分析。
[Objectives] To provide a technical basis for revealing the mechanism of olfactory reception, and chemoreceptive behavior in general, in insects. [Methods] Electroantennogram(EAG) signals of male Bombyx mori were measured after a portion of the antenna had been cut off and a parallel equivalent electrocircuit model of the resultant variations in EAG output were constructed. Correlations between actual EAG signals and the simulated circuit elements were analyzed. [Results] As long as 10 branches remained in the center of the antenna there was no significant difference in EAG amplitudes compared to an intact antenna. However, removal of additional elements of the antenna significantly decreased EAG amplitudes. Noise levels tended to increase, and SNR to decrease, as the number of antenna branches decreased. EAG amplitudes decreased in a linear fashion, as the number of branches on the center of the antenna decreased below 10. Removal of the top portion of the antenna trunk caused the EAG amplitude to increase and the noise level to decrease, thereby enhancing SNR. Removal of a basal portion of the antenna trunk caused EAG amplitude to decrease and the noise level to increase, thereby reducing SNR. A parallel equivalent electrocircuit model of EAG output, based on the impedance of the antenna trunk and branches, was constructed, that simulated the experimental results. [Conclusion] The impedance of the antenna trunk and branches have a great influence on the strength of the EAG signal. With some modifications, the parallel equivalent electrocircuit model developed in this study should be applicable to the experimental analysis of the EAG output of other insects.