Bodin Aurélie, Vinauger Clément, Lazzari Claudio R
Institut de Recherche sur la Biologie de l'Insecte, UMR 6035 CNRS-Université François Rabelais, Tours, France.
J Exp Biol. 2009 Aug;212(Pt 15):2386-93. doi: 10.1242/jeb.030668.
Vertebrate blood is essential for the growth and the reproduction of haematophagous insects. Provided that hosts play the double role of food sources and predators, feeding on their blood exposes these insects to a high predation risk. Therefore, it is expected that host seeking occurs only when insects need to feed. In the present study, we analyse how the feeding status affects the response to host-associated cues in the blood-sucking insect Rhodnius prolixus. We show that the responsiveness to host-associated cues, such as CO(2) and heat, and that the motivation to feed depend on the time elapsed since a blood meal. Depending on the time elapsed after feeding, the same concentration of CO(2) may attract or repel the insects. As far as we know, this is the first time that a host signal has been shown to be repellent for a haematophagous insect. The response to heat is also modulated but no repellence was observed. When blood was replaced by saline solution as food, a significant reduction of the response to both signals was evinced but repellence was not observed. The injection of haemolymph from fed insects into starved insects inhibited the response of the receiver insects to both signals but this was not observed after the injection of saline solution or of haemolymph from non-fed insects. This is the first time that the modulation of feeding behaviour by the feeding status has been analysed in a hemimetabolous blood-sucking insect, fully excluding any effect of other processes, such as reproduction.
脊椎动物的血液对吸血昆虫的生长和繁殖至关重要。鉴于宿主兼具食物来源和捕食者的双重角色，吸食宿主血液会使这些昆虫面临很高的被捕食风险。因此，可以预期，只有在昆虫需要进食时才会出现寻找宿主的行为。在本研究中，我们分析了进食状态如何影响吸血昆虫南美锥蝽对宿主相关线索的反应。我们发现，对宿主相关线索（如二氧化碳和热量）的反应以及进食动机取决于自上次吸血以来所经过的时间。根据进食后所经过的时间，相同浓度的二氧化碳可能会吸引或排斥这些昆虫。据我们所知，这是首次表明宿主信号对吸血昆虫具有驱避作用。对热量的反应也受到调节，但未观察到驱避现象。当用盐溶液替代血液作为食物时，对这两种信号的反应均显著降低，但未观察到驱避现象。将进食昆虫的血淋巴注射到饥饿昆虫体内会抑制受体昆虫对这两种信号的反应，但注射盐溶液或未进食昆虫的血淋巴后未观察到这种现象。这是首次在半变态吸血昆虫中分析进食状态对进食行为的调节作用，完全排除了其他过程（如繁殖）的任何影响。
