Genetic diversity and disease resistance in leaf-cutting ant societies
Genetic diversity and disease resistance in leaf-cutting ant societies
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DOI：
10.1111/j.0014-3820.2004.tb01704.x
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发表时间：
2004-06-01
期刊：
影响因子：
3.3
通讯作者：
Boomsma, JJ
中科院分区：
文献类型：
--
作者：
Hughes, WOH;Boomsma, JJ
女性的多次交配(一夫多妻制)仍然很难解释，因为尽管它有很大的成本，但明显的好处仍然难以捉摸。这个问题在群居昆虫中很严重，因为一夫多妻制对雌性来说可能特别昂贵，而且这种行为的大多数物质利益不太可能适用。有人提出，一夫多妻制的女王将产生更多样化的遗传劳动力，这可能会带来健康方面的好处。一种主要的假设是，工蚁基因多样性的增加将提高群体对疾病的抵抗力。我们使用一只多雄的切叶蚂蚁和一种致命的真菌寄生虫作为我们的模型系统来研究这一假说。在高剂量的寄生虫中，群体内的大多数父系也同样敏感，但少数表现出更大的抵抗力。在低剂量的寄生虫中，不同品系对寄生虫的抵抗力有较大的差异。这种遗传变异是一夫多妻制提高群体抗病能力的关键前提。两个宿主的亲缘关系似乎不会影响寄生虫在它们之间的传播，但这很可能是因为测试的寄生虫是一种毒力很强的多面手，适合在遥远的亲缘宿主之间传播。比较了遗传多样性高或低的小蚂蚁群体对这种寄生虫的抵抗力。在高剂量的寄生虫中没有发现差异，但在低剂量的寄生虫中发现高遗传多样性群体的抗性显著改善。抗病的遗传变异意味着一夫多妻制有可能产生更多的抗病群体。这种遗传变异即使在测试的有限条件下也能提高群体的抵抗力，这表明一夫多妻制确实可能产生对疾病抵抗力更强的群体。
Multiple mating by females (polyandry) remains hard to explain because, while it has substantial costs, clear benefits have remained elusive. The problem is acute in the social insects because polyandry is probably particularly costly for females and most material benefits of the behavior are unlikely to apply. It has been suggested that a fitness benefit may arise from the more genetically diverse worker force that a polyandrous queen will produce. One leading hypothesis is that the increased genetic diversity of workers will improve a colony's resistance to disease. We investigated this hypothesis using a polyandrous leaf-cutting ant and a virulent fungal parasite as our model system. At high doses of the parasite most patrilines within colonies were similarly susceptible, but a few showed greater resistance. At a low dose of the parasite there was more variation between patrilines in their resistance to the parasite. Such genetic variation is a key prerequisite for polyandry to result in increased disease resistance of colonies. The relatedness of two hosts did not appear to affect the transmission of the parasite between them, but this was most likely because the parasite tested was a virulent generalist that is adapted to transmit between distantly related hosts. The resistance to the parasite was compared between small groups of ants of either high or low genetic diversity. No difference was found at high doses of the parasite, but a significant improvement in resistance in high genetic diversity groups was found at a low dose of the parasite. That there is generic variation for disease resistance means that there is the potential for polyandry to produce more disease-resistant colonies. That this genetic variation can improve the resistance of groups even under the limited conditions tested suggests that polyandry may indeed produce colonies with improved resistance to disease.