Until recently, it was assumed that insects lack immune memory since they do not have vertebrate-like specialized memory cells. Therefore, their most well studied evolutionary response against pathogens was increased basal immunity. However, growing evidence suggests that many insects also exhibit a form of immune memory (immune priming), where prior exposure to a low dose of infection confers protection against subsequent infection by the same pathogen that acts both within and across generations. Most strikingly, they can rapidly evolve as a highly parallel and mutually exclusive strategy from basal immunity, under different selective conditions and with divergent evolutionary trade-offs. However, the relative importance of priming as an optimal immune strategy also has contradictions, primarily because supporting mechanisms are still unclear. In this review, we adopt a comparative approach to highlight several emerging evolutionary, ecological and mechanistic features of priming vs basal immune responses that warrant immediate attention for future research.

直到最近，人们还认为昆虫缺乏免疫记忆，因为它们没有类似脊椎动物的专门记忆细胞。因此，他们研究最多的针对病原体的进化反应是基础免疫力的增加。然而，越来越多的证据表明，许多昆虫还表现出一种形式的免疫记忆（免疫启动），即先前接触低剂量的感染可以防止随后受到在代内和代际间作用的相同病原体的感染。最引人注目的是，在不同的选择条件下和不同的进化权衡下，它们可以从基础免疫快速进化为高度平行和相互排斥的策略。然而，启动作为最佳免疫策略的相对重要性也存在矛盾，主要是因为支持机制仍不清楚。