Global climate change is predicted to cause range shifts in the mosquito species that transmit pathogens to humans and wildlife. Recent modeling studies have sought to improve our understanding of the relationship between temperature and the transmission potential of mosquito-borne pathogens. However, the role of the vertebrate host population, including the importance of host behavioral defenses on mosquito feeding success, remains poorly understood despite ample empirical evidence of its significance to pathogen transmission. Here, we derived thermal performance curves for mosquito and parasite traits and integrated them into two models of vector–host contact to investigate how vertebrate host traits and behaviors affect two key thermal properties of mosquito-borne parasite transmission: the thermal optimum for transmission and the thermal niche of the parasite population. We parameterized these models for five mosquito-borne parasite transmission systems, leading to two main conclusions. First, vertebrate host availability may induce a shift in the thermal optimum of transmission. When the tolerance of the vertebrate host to biting from mosquitoes is limited, the thermal optimum of transmission may be altered by as much as 5°C, a magnitude of applied significance. Second, thresholds for sustained transmission depend nonlinearly on both vertebrate host availability and temperature. At any temperature, sustained transmission is impossible when vertebrate hosts are extremely abundant because the probability of encountering an infected individual is negligible. But when host biting tolerance is limited, sustained transmission will also not occur at low host population densities. Furthermore, our model indicates that biting tolerance should interact with vertebrate host population density to adjust the parasite population thermal niche. Together, these results suggest that vertebrate host traits and behaviors play essential roles in the thermal properties of mosquito-borne parasite transmission. Increasing our understanding of this relationship should lead us to improved predictions about shifting global patterns of mosquito-borne disease.

中文翻译：

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宿主可用性和温度对蚊媒寄生虫传播的影响

预计全球气候变化将导致向人类和野生动物传播病原体的蚊子种类的范围发生变化。最近的模型研究试图提高我们对温度与蚊媒病原体传播潜力之间关系的理解。然而，尽管有充足的经验证据表明脊椎动物宿主群体的作用，包括宿主行为防御对蚊子摄食成功的重要性，但人们仍然知之甚少。在这里，我们得出了蚊子和寄生虫特征的热性能曲线，并将它们整合到媒介-宿主接触的两个模型中，以研究脊椎动物宿主特征和行为如何影响蚊媒寄生虫传播的两个关键热特性：传播的热最佳特性和传播的热特性。寄生虫种群的热生态位。我们对五个蚊媒寄生虫传播系统的这些模型进行了参数化，得出两个主要结论。首先，脊椎动物宿主的可用性可能会导致传输热最佳值的变化。当脊椎动物宿主对蚊子叮咬的耐受性有限时，最佳传播热可能会改变多达 5°C，这一幅度具有重要的应用意义。其次，持续传输的阈值非线性地取决于脊椎动物宿主的可用性和温度。在任何温度下，当脊椎动物宿主极其丰富时，持续传播都是不可能的，因为遇到感染个体的可能性可以忽略不计。但当宿主叮咬耐受性有限时，在宿主种群密度较低的情况下也不会发生持续传播。此外，我们的模型表明，叮咬耐受性应与脊椎动物宿主种群密度相互作用，以调整寄生虫种群的热生态位。总之，这些结果表明脊椎动物宿主的特征和行为在蚊媒寄生虫传播的热特性中发挥着重要作用。加深对这种关系的理解应该会让我们更好地预测全球蚊媒疾病模式的变化。