Parasites exert numerous effects upon their hosts, including physiological and metabolic changes that can in turn influence various aspects of host life history. Using flow‐through respirometry, we investigated how infection intensity of an ectoparasitic mite (Macrocheles subbadius) affects the respiratory rate (CO₂ production) of its host Drosophila nigrospiracula. Mean fly respiratory rate increased with infection intensity with the strongest effect, a 40% increase relative to uninfected controls, occurring with three mites attached. We also verified the causal relationship between elevated respiration rate and mite attachment by examining changes in host respiration before and after mite exposure. We found that the rate of CO₂ production increased by 11% for individual flies following parasite attachment. Fly locomotor activity was not significantly different between infected and uninfected individuals. Metabolic rate of hosts increased as a result of infection in an intensity dependent manner and was not simply due to changes in host activity. These results demonstrate that parasites can have a significant influence on the energy requirements of their host, which may account for the parasite‐mediated loss in host fitness.

中文翻译：

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寄生虫诱导的果蝇宿主代谢率增加

寄生虫对其宿主产生多种影响，包括生理和代谢变化，这些变化又可以影响宿主生活史的各个方面。我们使用流式呼吸法研究了寄生螨（Macrocheles subbadius）的感染强度如何影响其寄主果蝇（Drosophila nigrospiracula）的呼吸频率（CO ₂产生）。平均蝇呼吸速率随感染强度的增加而增加，效果最强，相对于未感染的对照，增加了40％，发生了三个螨虫。我们还通过检查螨暴露前后宿主呼吸的变化，验证了呼吸速率增加与螨附着之间的因果关系。我们发现CO ₂的比率寄生虫附着后，单个果蝇的产量增加了11％。感染者和未感染者之间的飞行自发活动没有显着差异。宿主的代谢率是由于感染而以强度依赖的方式增加的，而不仅仅是由于宿主活动的改变。这些结果表明，寄生虫可对其宿主的能量需求产生重大影响，这可能是寄生虫介导的宿主适应性丧失的原因。