Examination of the immune responses of males and workers of the leaf-cutting ant Acromyrmex echinatior and the effect of infection
Examination of the immune responses of males and workers of the leaf-cutting ant Acromyrmex echinatior and the effect of infection
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DOI：
10.1007/s00040-005-0809-x
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发表时间：
2005-01-01
期刊：
影响因子：
1.3
通讯作者：
Hughes, WOH
中科院分区：
文献类型：
--
作者：
Baer, B;Krug, A;Hughes, WOH
寄生虫对群居昆虫构成了重大挑战。种群内个体的高密度、互作率和亲缘性都预示着群居昆虫对寄生虫特别脆弱。为了应对这种压力，群居昆虫进化出了许多防御机制。其中包括免疫反应，除了在大黄蜂中，对群居昆虫的研究相对较少。在这里，我们比较了雄性和工蚁的免疫反应，并研究了先前暴露于一种剧毒寄生虫对免疫能力的影响。雄性的免疫反应远低于工蜂，这表明要么是单倍体易感性，要么是短命雄性在免疫方面的投入减少。雄蚁的免疫反应差异也明显小于工蚁，这可能是由于切叶蚁的年龄变化更大，或者在蚁群内的遗传多样性更大。当暴露于昆虫病原真菌绿僵菌时，工蚁在感染96小时后表现出明显降低的免疫反应，这表明免疫系统要么因必须对绿僵菌感染作出反应而耗尽，要么被寄生虫抑制。结果表明，免疫反应是一个昂贵和有限的过程，但需要进一步的实验来区分观察到的影响的其他解释。
Parasites represent significant challenges to social insects. The high density, interaction rate and relatedness of individuals within colonies are all predicted to make social insect colonies particularly vulnerable to parasites. To cope with this pressure, social insects have evolved a number of defence mechanisms. These include the immune response, which, aside from in bumblebees, has been relatively little studied in social insects. Here we compare the immune responses of males and workers of the leaf-cutting ant Acro-myrmex echinatior and examine the effect upon immunocompetence of prior exposure to a virulent parasite. Males have a far lower immune response than workers, suggesting either haploid susceptibility or reduced investment in immunity by the short-lived males. There was also significantly less variation in the immune response of males than of workers, which may be due to leaf-cutting ant workers being more variable in age or more genetically diverse within colonies. When exposed to the entomopathogenic fungus Metarhizium, workers expressed a substantially reduced immune response 96 h after infection, suggesting that the immune system was either depleted by having to respond to the Metarhizium infection or was depressed by the parasite. The results suggest that the immune response is a costly and limited process, but further experiments are needed to distinguish between the alternative explanations for the effects observed.