THE ROLES OF DENSITY, STAGE, AND PATCHINESS IN THE TRANSMISSION OF AN INSECT VIRUS
THE ROLES OF DENSITY, STAGE, AND PATCHINESS IN THE TRANSMISSION OF AN INSECT VIRUS
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DOI：
10.2307/2937196
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发表时间：
1991-04-01
期刊：
影响因子：
4.8
通讯作者：
DWYER, G
中科院分区：
文献类型：
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作者：
DWYER, G
尽管昆虫病毒在宿主种群动态中的重要性已被广泛认可，但生态学家对决定昆虫病毒在野外传播速度的因素仍然相对无知。我进行了一系列现场实验，研究了美国爱达荷州北部花旗松草蛾 Orgyia pestugata（鳞翅目：舞毒科）的核多角体病毒 (NPV) 的传播动态。在这些实验中，我在花旗松（Pseudotsuga menziesii）幼苗上一起饲养健康和感染的幼虫，并使用被感染的健康幼虫的数量作为传播的衡量标准。我通过操纵健康和感染宿主的密度和阶段分布以及感染宿主的空间分布，探索了密度、阶段结构和空间结构对传播的影响。实验表明，传播受到健康宿主和受感染宿主密度的强烈影响，但影响取决于每个宿主的龄期。晚龄草蛾幼虫比早龄草蛾幼虫更具传染性，也更容易被感染，因此 NPV 更有可能在晚龄草蛾幼虫群体中传播。我还发现传播受到感染宿主空间分布的影响，而且这种影响还取决于健康宿主的龄期。也就是说，向健康早期龄虫的传播随着受感染宿主斑块性的增加而减少，但向健康晚期龄虫的传播基本上不受斑块性的影响。我讨论了如何根据龄期之间的行为差异来解释这些结果，并将结果与疾病的数学理论和病毒在生物害虫控制中的使用联系起来。
Although the importance of insect viruses in the population dynamics of their hosts is widely acknowledged, ecologists are still relatively ignorant of the factors determining the rate of transmission of insect viruses in the field. I performed a series of field experiments in which I investigated the transmission dynamics of the nuclear polyhedrosis virus (NPV) of Douglas-fir tussock moth, Orgyia pseudotsugata (Lepidoptera: Lymantriidae), in northern Idaho, USA. In these experiments, I reared healthy and infected larvae together on seedling Douglas-fir (Pseudotsuga menziesii), and used the number of healthy larvae that became infected as a measure of transmission. I explored the influences of density, stage structure, and spatial structure on transmission by manipulating the density and stage distribution of healthy and infected hosts, and the spatial distribution of infected hosts. The experiments indicate that transmission is strongly affected by the densities of both healthy and infected hosts, but the effect depends on the instar of each. Late instars are both more infectious and more likely to become infected than are early instars, so that the NPV is more likely to spread in populations of late-instar tussock moth larvae. I also found that transmission is affected by the spatial distribution of infected hosts, and this effect also depends on the instar of healthy hosts. That is, transmission to healthy early instars decreases with increasing patchiness of infected hosts, but transmission to healthy late instars is essentially unaffected by patchiness. I discuss how these results can be interpreted in terms of behavioral differences among instars, and relate the results to the mathematical theory of disease and the use of viruses in biological pest control.