Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA.
Proc Biol Sci. 2013 May 22;280(1763):20130711. doi: 10.1098/rspb.2013.0711. Print 2013 Jul 22.
Previous studies have suggested that Plasmodium parasites can manipulate mosquito feeding behaviours such as probing, persistence and engorgement rate in order to enhance transmission success. Here, we broaden analysis of this 'manipulation phenotype' to consider proximate foraging behaviours, including responsiveness to host odours and host location. Using Anopheles stephensi and Plasmodium yoelii as a model system, we demonstrate that mosquitoes with early stage infections (i.e. non-infectious oocysts) exhibit reduced attraction to a human host, whereas those with late-stage infections (i.e. infectious sporozoites) exhibit increased attraction. These stage-specific changes in behaviour were paralleled by changes in the responsiveness of mosquito odourant receptors, providing a possible neurophysiological mechanism for the responses. However, we also found that both the behavioural and neurophysiological changes could be generated by immune challenge with heat-killed Escherichia coli and were thus not tied explicitly to the presence of malaria parasites. Our results support the hypothesis that the feeding behaviour of female mosquitoes is altered by Plasmodium, but question the extent to which this is owing to active manipulation by malaria parasites of host behaviour.
先前的研究表明，疟原虫寄生虫可以操纵蚊子的觅食行为，如探测、持续时间和吸血率，以提高传播成功率。在这里，我们扩大了对这种“操纵表型”的分析，以考虑包括对宿主气味和宿主位置的反应在内的近似觅食行为。我们使用斯氏按蚊和约氏疟原虫作为模型系统，证明了具有早期感染（即非感染性卵囊）的蚊子对人类宿主的吸引力降低，而具有晚期感染（即感染性孢子）的蚊子的吸引力增加。这些行为的阶段特异性变化与蚊子气味受体反应性的变化相平行，为这些反应提供了一种可能的神经生理学机制。然而，我们还发现，行为和神经生理学的变化都可以通过用热灭活的大肠杆菌进行免疫挑战来产生，因此这些变化与疟疾寄生虫的存在并没有明确的联系。我们的研究结果支持这样一种假设，即雌性蚊子的取食行为受到疟原虫的改变，但这种改变在多大程度上是由于疟原虫对宿主行为的主动操纵还存在疑问。
