【摘要】 为阐明生物胺对草地螟Loxostege sticticalis幼虫密度依赖抗病性的调控作用，在室内温度为(22±1)℃,相对湿度为70%,光周期为L//D=16 h//8 h条件下，探究了不同密度：低密度(1头/瓶)、高密度(10头/瓶)、超高密度(30头/瓶)饲养的草地螟幼虫抗病能力和3种生物胺含量，以及外源生物胺对幼虫抗病免疫的影响。结果表明，不同密度幼虫的抗病能力差异显著，高密度(10头/瓶)幼虫对球孢白僵菌Beauveria bassiana的抵抗能力显著高于低密度(1头/瓶)和超高密度(30头/瓶)幼虫。高密度的幼虫血淋巴中章鱼胺含量明显高于其他2个密度。不同密度幼虫血淋巴中多巴胺和5-羟色胺的含量无显著变化。注射不同浓度(2、20、200μg/mL)外源章鱼胺后，幼虫被球孢白僵菌侵染后的存活率显著升高，对球孢白僵菌的抵抗能力明显增强。注射20μg/mL章鱼胺后，幼虫的酚氧化酶活性和血细胞包囊作用明显增强，血细胞总数显著增多，血细胞包囊率显著增加。以上结果表明，章鱼胺可调控草地螟幼虫的免疫功能以增强其抗病能力。因此，章鱼胺在草地螟幼虫密度依赖抗病免疫中具有重要作用。更多还原

【Abstract】 To clarify the regulatory role of biogenic amines in density-dependent disease resistance in Loxostege sticticalis larvae, this study investigated disease resistance and biogenic amine levels of larvae reared at different larval densities: high density(10 larvae/jar), low density(1 larva/jar), and ultra-high density(30 larvae/jar) under controlled laboratory conditions [temperature:(22 ± 1)℃, relative humidity: 70%, photoperiod: L//D=16 h//8 h], and the effects of exogenous biogenic amines on the larval disease resistance and immunity. The results showed that disease resistance varied significantly across densities. High-density larvae(10 larvae/jar) exhibited significantly greater resistance to Beauveria bassiana than low-density larvae(1 larva/jar), while ultra-high-density larvae(30 larvae/jar) had significantly lower resistance. High-density larvae had significantly higher octopamine content than those at low-density and ultra-high-density. Dopamine and serotonin levels showed no significant differences among density groups. Exogenous octopamine injection enhanced disease resistance. Injection of 2, 20, 200 μg/mL octopamine increased survival rates following B.bassiana infection. Injection of 20 μg/mL octopamine resulted in increased phenoloxidase activity and hemocyte encapsulation, and a significant increase in total number of hemocytes and encapsulation rate. These results indicate that octopamine regulates the immune function of L.sticticalis larvae, enhancing disease resistance in high-density populations. Therefore, octopamine plays an important role in density-dependent disease resistance in L.sticticalis.更多还原