Baker T C, Hansson B S, Löfstedt C, Löfqvist J
Department of Animal Ecology, University of Lund, Sweden.
Proc Natl Acad Sci U S A. 1988 Dec;85(24):9826-30. doi: 10.1073/pnas.85.24.9826.
A wind-borne plume of sex pheromone from a female moth or a synthetic source has a fine, filamentous structure that creates steep and rapid fluctuations in concentration for a male moth flying up the plume's axis. The firing rates from single antennal neurons on Agrotis segetum antennae decreased to nearly zero within seconds after the antennae were placed in a pheromone plume 70 cm downwind of a high-concentration source known from previous studies to cause in-flight arrestment of upwind progress. In a separate experiment, the fluctuating output from chilled neurons on Grapholita molesta antennae became attenuated in response to repetitive, experimentally delivered pheromone pulses. The attenuation was correlated with a previously reported higher percentage of in-flight arrestment exhibited by moths flying at cooler compared to warmer temperatures. These results indicate that two peripheral processes related to excessive concentration, complete adaptation of antennal neurons, or merely the attenuation of fluctuations in burst frequency, are important determinants of when upwind progress by a moth flying in a pheromone plume stops and changes to station keeping. Also, adaptation and attenuation may affect the sensation of blend quality by preferentially affecting cells sensitive to the most abundant components in airborne pheromone blends.
来自雌蛾或合成源的性信息素随风传播形成的羽流具有精细的丝状结构，对于沿羽流轴线向上飞行的雄蛾而言，这种结构会导致浓度急剧快速波动。将黄地老虎触角置于高浓度源顺风70厘米处的信息素羽流中后，单根触角神经元的放电频率在数秒内降至几乎为零，此前研究表明该高浓度源会导致飞行中的雄蛾逆风前进受阻。在另一项实验中，苹果蠹蛾触角上经过冷却的神经元的波动输出，会因实验性传递的重复性信息素脉冲而减弱。这种减弱与之前报道的结果相关，即与处于较温暖温度下飞行的蛾子相比，处于较凉爽温度下飞行的蛾子在飞行中受阻的比例更高。这些结果表明，与浓度过高相关的两个外周过程，即触角神经元的完全适应，或仅仅是脉冲频率波动的减弱，是决定在性信息素羽流中飞行的蛾子何时停止逆风前进并转变为原地停留的重要因素。此外，适应和减弱可能会通过优先影响对空气中性信息素混合物中最丰富成分敏感的细胞，来影响混合物质量的感知。
