Mating dynamics follow from natural selection on mate choice and individuals maximizing their reproductive success. Mate discrimination reveals itself by a plethora of behaviours and morphological characteristics, each of which can be affected by pathogens. A key question is how pathogens affect mate choice and outcrossing behaviour. Here we investigated the effect of Orsay virus on the mating dynamics of the androdiecious (male and hermaphrodite) nematode Caenorhabditis elegans. We tested genetically distinct strains and found that viral susceptibility differed between sexes in a genotype-dependent manner with males of reference strain N2 being more resistant than hermaphrodites. Males displayed a constitutively higher expression of intracellular pathogen response (IPR) genes, whereas the antiviral RNAi response did not have increased activity in males. Subsequent monitoring of sex ratios over 10 generations revealed that viral presence can change mating dynamics in isogenic populations. Sexual attraction assays showed that males preferred mating with uninfected rather than infected hermaphrodites. Together our results illustrate for the first time that viral infection can significantly affect male mating choice and suggest altered mating dynamics as a novel cause benefitting outcrossing under pathogenic stress conditions in C. elegans.

中文翻译：

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病毒感染调节秀丽隐杆线虫的男性性行为

交配动力学遵循自然选择的配偶选择和个体最大化其繁殖成功率。配偶歧视通过过多的行为和形态特征表现出来，每一种行为和形态特征都可能受到病原体的影响。一个关键问题是病原体如何影响配偶选择和异交行为。在这里，我们研究了奥赛病毒对雌雄同株（雄性和雌雄同体）线虫秀丽隐杆线虫交配动力学的影响. 我们测试了遗传上不同的毒株，发现病毒易感性以基因型依赖的方式在两性之间存在差异，参考毒株 N2 的雄性比雌雄同体更具抵抗力。男性表现出更高的细胞内病原体反应 (IPR) 基因表达，而抗病毒 RNAi 反应在男性中没有增加的活性。随后对超过 10 代的性别比例的监测表明，病毒的存在可以改变等基因种群的交配动态。性吸引力分析表明，雄性更喜欢与未感染而不是感染的雌雄同体交配。C. _ 线虫。