Transmission and temporal dynamics of anther-smut disease (Microbotryum) on alpine carnation (Dianthus pavonius)

1. Theory has shown that sterilizing diseases with frequency-dependent transmission (characteristics shared by many sexually transmitted diseases) can drive host populations to extinction. 2. Anther-smut disease (caused by Microbotryum sp.) has become a model plant pathogen system for studying the dynamics of vector and sexually transmitted diseases: infected individuals are sterilized, producing spores instead of pollen, and the disease is spread between reproductive individuals by insect pollinators. We investigated anther-smut disease in a heavily infected population of Dianthus pavonius (alpine carnation) over an eight-year period to determine disease impacts on host population dynamics. 3. Over the eight years, disease prevalence remained consistently high (>40%) while the host population numbers declined by over 50%. 4. The observed rate of vector transmission to reproductive, adult hosts was inadequate to explain the high disease prevalence. Additional density-dependent aerial...1. 已有理论研究表明，频率依赖型传播的致病绝育型疾病（此类传播特征与多数性传播疾病一致）可引发宿主种群灭绝。 2. 由黑粉菌属（Microbotryum sp.）引起的花药黑粉病（Anther-smut disease），现已成为研究媒介传播与性传播疾病动态的经典植物病原模式系统。该病害的染病个体将丧失育性，不再产生花粉转而生成孢子，且通过昆虫传粉者在繁殖个体间扩散。本研究针对一个感染程度极高的高山石竹（Dianthus pavonius）种群开展了为期8年的调查，旨在明确该病害对宿主种群动态的影响。 3. 在这8年的调查周期内，病害流行率始终维持在40%以上的高位，而宿主种群数量则下降了50%以上。 4. 观测到的媒介向繁殖期成体宿主的传播速率，不足以解释该病害的高流行率。额外的依赖密度的气传传播途径……