Sex differences in immune investment and infection rate are predicted due to the divergent life histories of males and females, where females invest more toward immunity due to the fitness consequences of a reduced lifespan and males allocate less toward immunity due to increased resource investment in traits critical to sexual selection. Consequently, males are expected to fight infection less adeptly, resulting in higher parasite loads relative to females across all taxa. Wild animals rarely face a single parasite within their given environment, yet nearly all studies on sex‐biased infection rates have focused on a single host–parasite relationship. Here, we investigate how simultaneous natural infections of ecto‐ and endosymbionts (i.e. both parasitic and phoretic taxa) correlate with sex biases in host immune response and reproductive investment in a field‐caught cricket, Gryllus texensis. Our comprehensive analysis found no significant sex differences in two measures of immune response (melanization and nodulation), and found no strong evidence of a sex bias in the prevalence or intensity of parasitism by the three most common parasites infecting wild G. texensis field crickets (Eutrombidiidae, gregarines, and nematodes). Two traits related to female fitness, egg number and egg size, showed no relation to parasitic infection; however, males having wider heads and poorer body condition were significantly more infected by eutrombidiid mites, gregarines, and nematodes. Despite frequent predictions of male‐biased parasitism in the literature, our results concur with many other studies indicating that the divergent life histories of males and females alone are not sufficient to explain natural infection rates in wild insects.

中文翻译：

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野生捕捞的德克萨斯蟋蟀（Gryllus texensis）寄生虫感染与性和生活史特征的弱关系

由于男性和女性的生活史不同，因此预测免疫投资和感染率的性别差异，其中由于寿命缩短的健康后果，女性对免疫的投资更多，而由于对关键性状的资源投资增加，男性对免疫的分配较少性选择。因此，预计雄性对抗感染的能力较差，导致所有分类群中相对于雌性的寄生虫负荷更高。野生动物在其特定环境中很少面临单一寄生虫，但几乎所有关于性别偏见感染率的研究都集中在单一宿主 - 寄生虫关系上。在这里，我们研究了外共生体和内共生体的同时自然感染（即 寄生和泳动类群）与宿主免疫反应和田间蟋蟀 Gryllus texensis 生殖投资的性别偏见相关。我们的综合分析发现两种免疫反应指标（黑化和结瘤）没有显着的性别差异，并且没有发现强烈的证据表明感染野生 G. texensis 蟋蟀的三种最常见寄生虫的寄生流行率或强度存在性别偏见。 Eutrombidiidae、gregarines 和线虫）。与雌性健康相关的两个性状，卵数和卵大小，与寄生虫感染无关；然而，头部较宽且身体状况较差的雄性明显更多地感染了eutrombidiid螨类、合群螨和线虫。尽管文献中经常预测有男性偏见的寄生现象，