Phenology is a fundamental determinant of species distributions, abundances, and interactions. In host–parasite interactions, host phenology can affect parasite fitness due to the temporal constraints it imposes on host contact rates. However, it remains unclear how parasite transmission is shaped by the wide range of phenological patterns observed in nature. We develop a mathematical model of the Lyme disease system to study the consequences of differential tick developmental-stage phenology for the transmission of B. burgdorferi. Incorporating seasonal tick activity can increase B. burgdorferi fitness compared to continuous tick activity but can also prevent transmission completely. B. burgdorferi fitness is greatest when the activity period of the infectious nymphal stage slightly precedes the larval activity period. Surprisingly, B. burgdorferi is eradicated if the larval activity period begins long after the end of nymphal activity due to a feedback with mouse population dynamics. These results highlight the importance of phenology, a common driver of species interactions, for the fitness of a parasite.

物候是物种分布、丰度和相互作用的基本决定因素。在宿主 - 寄生虫相互作用中，宿主物候可以影响寄生虫适应性，因为它对宿主接触率施加了时间限制。然而，目前尚不清楚自然界中观察到的各种物候模式如何影响寄生虫传播。我们开发了莱姆病系统的数学模型，以研究差异蜱发育阶段物候学对伯氏疏螺旋体传播的影响。与持续的蜱活动相比，加入季节性蜱活动可以增加伯氏疏螺旋体的适应性，但也可以完全防止传播。伯氏疏螺旋体当传染性若虫阶段的活动期稍早于幼虫活动期时，适应度最大。令人惊讶的是，如果幼虫活动期在若虫活动结束后很长时间由于小鼠种群动态的反馈而开始，则伯氏疏螺旋体将被根除。这些结果强调了物候学对寄生虫适应性的重要性，这是物种相互作用的常见驱动因素。