1. The hypothesis of community‐wide character displacement (CWCD) predicts that coexisting species in the same guild should differ in morphological traits associated with resource acquisition, such that interspecific competition is unlikely. Hypothesis tests often focus on trophic structures involved in food acquisition, because variations in the morphology of foraging apparatus and diet composition may be directly related. Empirical evidence of such associations among sympatric guild members is, however, uncommon.
2. The predatory larvae of caddisflies in the family Hydrobiosidae are ideal for studies of CWCD because the morphology of the prehensile foreleg, used to capture prey, varies markedly among genera. Further, hydrobiosids typically occur as species‐rich guilds, often with 10–20 species in a single community. Although the larvae are known to be predatory, detailed information on the diet of coexisting species is scarce. This study tested whether larval diet varied among multiple, sympatric species of hydrobiosid caddisflies that differed in foreleg morphology.
3. Larval specimens were collected in summer and primarily from one river in central Victoria, Australia. Gut contents of late instar larvae were examined to describe diet composition, and diet was compared among taxa using measures of diet breadth and overlap.
4. Seven sympatric species from six genera that differed in foreleg morphology were collected and late instar larvae were exclusively carnivorous. Diet composition and breadth varied markedly among some species, and diet was associated with morphology of the prehensile foreleg. Specialist predator species consumed predominantly chironomids and had high diet overlap. Generalists consumed primarily chironomids and mayflies, but overlap varied depending upon the preferred mayfly family and representation of other prey items, such as blackflies and insect eggs. All predator species consumed some caseless caddisflies and intraguild predation was strong in at least one species.
5. The marked differences in diet and foreleg morphology among hydrobiosid species are consistent with the notion that CWCD influences guild membership and may facilitate species coexistence within guilds that are typically species‐rich. Although rarely considered for freshwater communities, CWCD may help explain species membership within other guilds. The magnitude of diet variations among genera within this family are more usually found across multiple families or orders, demonstrating that assumptions about the diet of even closely related taxa may be erroneous.

中文翻译：

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饲养设备和饮食的形态变化可以促进捕食性虫种类的共存

1. 社区性角色置换（CWCD）的假设预测，同一行会中并存的物种在与资源获取相关的形态特征上应该有所不同，因此种间竞争是不可能的。假设检验通常侧重于食物获取中的营养结构，因为觅食设备的形态和饮食组成的变化可能直接相关。但是，同胞行会成员之间这种联系的经验证据并不常见。
2. 水生生物科中的虫的捕食性幼虫非常适合于CWCD的研究，因为用于捕获猎物的捕蝇前肢的形态在属间显着不同。此外，水生生物素通常以物种丰富的行会的形式出现，通常在一个群落中有10–20种。尽管幼虫是捕食性的，但是关于共存物种饮食的详细信息却很少。这项研究测试了幼虫的饮食是否在前肢形态不同的多种同生水生虫齿甲虫之间变化。
3. 幼虫标本是在夏季采集的，主要是从澳大利亚维多利亚州中部的一条河中采集的。检查晚in幼虫的肠道含量以描述饮食组成，并使用饮食宽度和重叠度的方法比较各类群的饮食。
4. 收集了来自六个属的前肢形态不同的七个同胞种，而晚龄幼虫仅是肉食性的。饮食组成和广度在某些物种中有显着差异，并且饮食与鱼类前肢的形态有关。特殊的捕食者物种主要食用猫足纲动物，并且饮食重叠率高。通才主要食用猫科动物和may类，但重叠程度取决于首选的fly类和其他猎物（例如黑蝇和虫卵）的代表。所有的捕食者物种都消耗了一些无壳的and虫，并且至少有一个物种的行会内部掠夺性很强。
5. 水生生物物种之间饮食和前肢形态的显着差异与CWCD影响公会成员资格并可能促进通常在物种丰富的公会中物种共存的观点一致。尽管很少为淡水社区考虑，但CWCD可能有助于解释其他行会中物种的成员资格。该家族中不同属间饮食差异的大小更常见于多个家庭或订单中，这表明即使是关系密切的类群的饮食假设也可能是错误的。