Predators should be selected to maximize their fitness by catching the most profitable prey. As predators grow in size, they often shift their preferences to larger prey during the course of development. Alike generalist predators, specialized predators should also shift to larger prey within the pool of focal prey. Here, we have studied the natural diet of a specialized ant‐eating spider Zodarion rubidum by means of molecular methods. We tested the hypothesis of a trophic shift during postembryonic ontogenesis and if there is a difference in the diet between sexes due to sexual dimorphism. In addition, a feeding trial was performed to estimate the time at which prey DNA can be detected. The diet of all stages consisted solely of ants (nine genera), thus confirming their strict ant specialization. There was no shift in prey size or prey type during ontogenetic development, but the diversity of prey declined with age. In adult males, very few prey were detected. The feeding trial showed that prey DNA can be detected inside the spider's gut up to 2 weeks after feeding.

中文翻译：

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食蚁蜘蛛在整个个体发育过程中均保持专业饮食

应该选择捕食者，以捕获最有利可图的猎物，从而最大程度地提高其适应能力。随着捕食者规模的增长，他们经常在发展过程中将偏好转移到更大的猎物上。像通才捕食者一样，专业捕食者也应转移到焦点猎物池中的更大猎物。在这里，我们研究了专门食蚁蜘蛛Zodarion rubidum的天然饮食通过分子方法。我们检验了胚胎后本体发育过程中营养转移的假设，以及由于性别二态性导致的性别饮食差异。另外，进行了一次饲喂试验以估计可以检测到猎物DNA的时间。所有阶段的饮食都只包含蚂蚁（九属），因此证实了它们严格的蚂蚁专长。在个体发育过程中，猎物的大小或种类没有变化，但是猎物的多样性随着年龄的增长而下降。在成年雄性中，很少发现猎物。喂食试验表明，喂食后2周内可以在蜘蛛肠内检测到猎物DNA。