Data from: Senescence in immune priming and attractiveness in a beetle

Age-related decline in immune activity is referred to as immunosenescence and has been observed for both the adaptive immune response of vertebrates and the innate immune system of invertebrates. Since maintaining a basic level of immune defence and mounting an immune response is costly, optimal investment in immune function should vary over a wide range of individual states such as the individual’s age. In this study we tested whether the immune response and immunological priming within individuals become less efficient with age using mealworm beetles, Tenebrio molitor, as a model organism. We also tested whether aging and immunological priming affected the odours produced by males. We found that young males of T.molitor were capable of mounting an immune response a sterile nylon monofilament implant with the potential to exhibit a simple form of immune memory through mechanisms of immune priming. Older males did not increase their immune response to a second immune challenge, which negatively affected their sexual attractiveness and remaining life span. Our results indicate that the immune system of older males in T.molitor is less effective, suggesting complex evolutionary trade-offs between ageing, immune response and sexual attractiveness.

与年龄相关的免疫活性下降被称为免疫衰老（immunosenescence），该现象在脊椎动物的适应性免疫应答以及无脊椎动物的先天免疫系统中均有观测报道。由于维持基础免疫防御水平与启动免疫应答均存在代谢成本，因此针对免疫功能的最优投入应当随个体的多种状态（如年龄）发生动态变化。本研究以黄粉虫（Tenebrio molitor）作为模式生物，探究个体的免疫应答与免疫致敏（immunological priming）效率是否会随年龄增长而下降。此外，本研究还探究了衰老与免疫致敏是否会影响雄性个体所释放的气味信号。研究结果显示，黄粉虫的年轻雄性个体能够对无菌尼龙单丝植入物产生免疫应答，并可通过免疫致敏机制形成简单的免疫记忆。而年长雄性个体则无法在第二次免疫刺激下增强其免疫应答，这一情况对其性吸引力与剩余寿命均产生了负面影响。本研究结果表明，黄粉虫年长雄性的免疫系统功能有所衰退，这暗示了衰老、免疫应答与性吸引力之间存在复杂的进化权衡。