褐飞虱成虫体内磁性物质检测

Detection of magnetic materials in adults of the brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae)

地磁定向是昆虫远距离迁飞定向的重要机制之一。本研究以褐飞虱Nilaparvata lugens长翅型和短翅型成虫为研究对象,利用MPMS-7型号超导量子干涉磁强计(磁场范围为±4.8mA/m,温度范围为1.9～400K)检测虫体内的磁性物质,明确其体内的分布状况。结果表明:褐飞虱长翅型雄成虫整个虫体的温度退磁曲线在T=220K处无明显拐点,磁滞回线无明显闭合现象;长翅型雌成虫及短翅型雌、雄成虫整体磁性物质检测结果与长翅型雄成虫类似,说明利用成虫整体进行磁性物质检测效果不明显。分体段检测时,褐飞虱短翅型和长翅型雌、雄成虫腹部温度退磁曲线在T=220K处有明显拐点,且磁滞回线明显闭合,说明该部位有磁滞(即矫顽力)存在,也即存在着磁性物质;而短翅型和长翅型雌、雄成虫头胸部的磁滞回线无闭合现象,说明该部位无磁性物质存在。褐飞虱虫体内磁性物质的存在为其远距离迁飞过程中实现地磁定向提供了物质基础。

The geomagnetic orientation is one of the important mechanisms for orientation of insects in the long distance migration. In this study, the long-winged and short-winged adults of the brown planthopper, Nilaparvata lugens, were selected to detect magnetic materials using Superconducting Quantum Interference Magnetometer （magnetic field range： ±4.8 mA/m; temperature range： 1.9-400 K） and to ascertain their distribution in the body. The results showed that there was no obvious turning point at T=220 K in temperature-demagnetization curve and no closed hysteresis loop in the whole body of long-winged male adults of N. lugens. Similar phenomena were found in long-winged female adults and short-winged male and female adults, suggesting that the detection of magnetic materials using whole insect body is not obvious. When tested using body segments, the turning points of temperature-demagnetization curves were obviously detected at T=220 K, and hysteresis loops were also clearly closed in the abdomen of long-winged and short-winged adults, suggesting that hysteresis （i.e., coercive force） or magnetic materials exist in the abdomen of N. lugens. In the meantime, there were no closed hysteresis loops detected in the cephalothorax of long-winged and short-winged adults, suggesting that no magnetic materials exist in this body part of N. lugens. The existence of magnetic materials in the body of N. lugens provides physical basis for its geomagnetic orientation during the long distance migration.